1 /*! \page faq Frequently Asked Questions
3 \htmlinclude .FAQ.doc.toc
5 \section faq_simgrid I'm new to SimGrid. I have some questions. Where should I start?
7 You are at the right place... Having a look to these
8 <a href="http://www.loria.fr/~quinson/articles/simgrid-tutorial.pdf">the tutorial slides</a>
9 (or to these <a href="http://graal.ens-lyon.fr/~alegrand/articles/slides_g5k_simul.pdf">old slides</a>,
11 <a href="http://graal.ens-lyon.fr/~alegrand/articles/Simgrid-Introduction.pdf">"obsolete" slides</a>)
12 may give you some insights on what SimGrid can help you to do and what
13 are its limitations. Then you definitely should read the \ref
14 MSG_examples. The \ref GRAS_tut can also help you.
16 If you are stuck at any point and if this FAQ cannot help you, please drop us a
17 mail to the user mailing list: <simgrid-user@lists.gforge.inria.fr>.
19 \subsection faq_interfaces What is the difference between MSG, SimDag, and GRAS? Do they serve the same purpose?
21 It depend on how you define "purpose", I guess ;)
23 They all allow you to build a prototype of application which you can run
24 within the simulator afterward. They all share the same simulation kernel,
25 which is the core of the SimGrid project. They differ by the way you express
28 With SimDag, you express your code as a collection of interdependent
29 parallel tasks. So, in this model, applications can be seen as a DAG of
30 tasks. This is the interface of choice for people wanting to port old
31 code designed for SimGrid v1 or v2 to the framework current version.
33 With both GRAS and MSG, your application is seen as a set of communicating
34 processes, exchanging data by the way of messages and performing computation
37 The difference between both is that MSG is somehow easier to use, but GRAS
38 is not limited to the simulator. Once you're done writing your GRAS code,
39 you can run your code both in the simulator or on a real platform. For this,
40 there is two implementations of the GRAS interface, one for simulation, one
41 for real execution. So, you just have to relink your code to chose one of
44 \subsection faq_generic First steps with SimGrid
46 If you decide to go for the MSG interface, please read carefully the
47 \ref MSG_examples. You'll find in \ref MSG_ex_master_slave a very
48 simple consisting of a master (that owns a bunch of tasks and
49 distributes them) , some slaves (that process tasks whenever they
50 receive one) and some forwarder agents (that simply pass the tasks
51 they receive to some slaves).
53 If you decide to go for the GRAS interface, you should definitively
54 read the \ref GRAS_tut. The first section constitutes an introduction
55 to the tool and presents the model we use. The second section
56 constitutes a complete step-by-step tutorial building a distributed
57 application from the beginning and exemplifying most of the GRAS
58 features in the process. The last section groups some HOWTOS
59 highlighting a given feature of the framework in a more concise way.
61 If you decide to go for another interface, I'm afraid your only sources
62 of information will be the source code and the mailing lists...
64 \subsection faq_visualization Visualizing and analyzing the results
66 It is sometime convenient to "see" how the agents are behaving. If you
67 like colors, you can use <tt>tools/MSG_visualization/colorize.pl </tt>
68 as a filter to your MSG outputs. It works directly with INFO. Beware,
69 INFO() prints on stderr. Do not forget to redirect if you want to
70 filter (e.g. with bash):
72 ./msg_test small_platform.xml small_deployment.xml 2>&1 | ../../tools/MSG_visualization/colorize.pl
75 We also have a more graphical output. Have a look at section \ref faq_tracing.
77 \subsection faq_C Argh! Do I really have to code in C?
79 Up until now, there is no binding for other languages. If you use C++,
80 you should be able to use the SimGrid library as a standard C library
81 and everything should work fine (simply <i>link</i> against this
82 library; recompiling SimGrid with a C++ compiler won't work and it
83 wouldn't help if you could).
85 In fact, we are currently working on Java bindings of MSG to allow
86 all the undergrad students of the world to use this tool. This is a
87 little more tricky than I would have expected, but the work is moving
88 fast forward [2006/05/13]. More languages are evaluated, but for now,
89 we do not feel a real demand for any other language. Please speak up!
91 \section faq_installation Installing the SimGrid library
93 Many people have been asking me questions on how to use SimGrid. Quite
94 often, the questions were not really about SimGrid but on the
95 installation process. This section is intended to help people that are
96 not familiar with compiling C files under UNIX. If you follow these
97 instructions and still have some troubles, drop an e-mail to
98 <simgrid-user@lists.gforge.inria.fr>.
100 \subsection faq_compiling Compiling SimGrid from a stable archive
102 First of all, you need to download the latest version of SimGrid from
103 <a href="http://gforge.inria.fr/frs/?group_id=12">here</a>.
104 Suppose you have uncompressed SimGrid in some temporary location of
105 your home directory (say <tt>/home/joe/tmp/simgrid-3.0.1 </tt>). The
106 simplest way to use SimGrid is to install it in your home
107 directory. Change your directory to
108 <tt>/home/joe/tmp/simgrid-3.0.1</tt> and type
111 ./configure --prefix=$HOME
116 If at some point, something fails, check the section \ref faq_trouble_compil .
117 If it does not help, you can report this problem to the
118 list but, please, avoid sending a laconic mail like "There is a problem. Is it
119 okay?". Send the config.log file which is automatically generated by
120 configure. Try to capture both the standard output and the error output of the
121 <tt>make</tt> command with <tt>script</tt>. There is no way for us to help you
122 without the relevant bits of information.
124 Now, the following directory should have been created :
126 \li <tt>/home/joe/doc/simgrid/html/</tt>
127 \li <tt>/home/joe/lib/</tt>
128 \li <tt>/home/joe/include/</tt>
130 SimGrid is not a binary, it is a library. Both a static and a dynamic
131 version are available. Here is what you can find if you try a <tt>ls
134 \verbatim libsimgrid.a libsimgrid.la libsimgrid.so libsimgrid.so.0 libsimgrid.so.0.0.1
137 Thus, there is two ways to link your program with SimGrid:
138 \li Either you use the static version, e.g
139 \verbatim gcc libsimgrid.a -o MainProgram MainProgram.c
141 In this case, all the SimGrid functions are directly
142 included in <tt>MainProgram</tt> (hence a bigger binary).
143 \li Either you use the dynamic version (the preferred method)
144 \verbatim gcc -lsimgrid -o MainProgram MainProgram.c
146 In this case, the SimGrid functions are not included in
147 <tt>MainProgram</tt> and you need to set your environment
148 variable in such a way that <tt>libsimgrid.so</tt> will be
149 found at runtime. This can be done by adding the following
150 line in your .bashrc (if you use bash and if you have
151 installed the SimGrid libraries in your home directory):
152 \verbatim export LD_LIBRARY_PATH=$HOME/lib/:$LD_LIBRARY_PATH
155 \subsection faq_compiling_java Java bindings don't get compiled
157 The configure script detects automatically whether you have the
158 softwares needed to use the Java bindings or not. At the end of the
159 configure, you can see the configuration picked by the script, which
160 should look similar to
161 \verbatim Configuration of package simgrid' (version 3.3.4-svn) on
164 Compiler: gcc (version: )
166 CFlags: -O3 -finline-functions -funroll-loops -fno-strict-aliasing -Wall -Wunused -Wmissing-prototypes -Wmissing-declarations -Wpointer-arith -Wchar-subscripts -Wcomment -Wformat -Wwrite-strings -Wno-unused-function -Wno-unused-parameter -Wno-strict-aliasing -Wno-format-nonliteral -Werror -g3
170 Context backend: ucontext
177 In this example, Java backends won't be compiled.
179 On Debian-like systems (which includes ubuntu), you need the following
180 packages: sun-java6-jdk libgcj10-dev. If you cannot find the
181 libgcj10-dev, try another version, like libgcj9-dev (on Ubuntu before
182 9.10) or libgcj11-dev (not released yet, but certainly one day).
183 Please note that you need to activate the contrib and non-free
184 repositories in Debian, and the universe ones in Ubuntu. Java comes at
187 \subsection faq_compiling_snapshoot SimGrid development snapshots
189 We have very high standards on software quality, and we are reluctant releasing
190 a stable release as long as there is still some known bug in the code base. In
191 addition, we added quite an extensive test base, making sure that we correctly
192 test the most important parts of the tool.
194 As an unfortunate conclusion, there may be some time between the stable
195 releases. If you want to benefit from the most recent features we introduced,
196 but don't want to take the risk of an untested version from the SVN, then
197 development snapshots are done for you.
199 These are pre-releases of SimGrid that still fail some tests about features
200 that almost nobody use, or on platforms not being in our core target (which is
201 Linux, Mac, other Unixes and Windows, from the most important to the less
202 one). That means that using this development releases should be safe for most
205 These archives can be found on
206 <a href="http://www.loria.fr/~quinson/simgrid.html">this web page</a>. Once you
207 got the lastest archive, you can compile it just like any archive (see above).
209 \subsection faq_compiling_svn Compiling SimGrid from the SVN
211 The project development takes place in the SVN, where all changes are
212 committed when they happen. Then every once in a while, we make sure that the
213 code quality meets our standard and release an archive from the code in the
214 SVN. We afterward go back to the development in the SVN. So, if you need a
215 recently added feature and can afford some little problem with the stability
216 of the lastest features, you may want to use the SVN version instead of a
219 For that, you first need to get the "simgrid" module from
220 <a href="http://gforge.inria.fr/scm/?group_id=12">here</a>.
222 You won't find any <tt>configure</tt> and a few other things
223 (<tt>Makefile.in</tt>'s, documentation, ...) will be missing as well. The
224 reason for that is that all these files have to be regenerated using the
225 latest versions of <tt>autoconf</tt>, <tt>libtool</tt>, <tt>automake</tt>
226 (>1.9) and <tt>doxygen</tt> (>1.4). To generate the <tt>configure</tt> and
227 the <tt>Makefile.in</tt>'s, you just have to launch the <tt>bootstrap</tt>
228 command that resides in the top of the source tree. Then just follow the
229 instructions of Section \ref faq_compiling.
231 We insist on the fact that you really need the latest versions of
232 autoconf, automake and libtool. Doing this step on exotic architectures/systems
233 (i.e. anything different from a recent linux distribution) may be
234 ... uncertain. If you need to compile the SVN version on a machine where all these
235 dependencies are not met, the easiest is to do <tt>make dist</tt> in the SVN
236 directory of another machine where all dependencies are met. It will create an
237 archive you may deploy on other sites just as a regular stable release.
239 In summary, the following commands will checkout the SVN, regenerate the
240 configure script and friends, configure SimGrid and build it.
242 \verbatim svn checkout svn://scm.gforge.inria.fr/svn/simgrid/simgrid/trunk simgrid
245 ./configure --enable-maintainer-mode --prefix=<where to install SimGrid>
248 Then, if you want to install SimGrid on the current box, just do:
249 \verbatim make install \endverbatim
251 If you want to build an snapshot of the SVN to deploy it on another box (for
252 example because the other machine don't have the autotools), do:
253 \verbatim make dist \endverbatim
255 Moreover, you should never call the autotools manually since you must run
256 them in a specific order with specific arguments. Most of the times, the
257 makefiles will automatically call the tools for you. When it's not possible
258 (such as the first time you checkout the SVN), use the ./bootstrap command
259 to call them explicitly.
262 \subsection faq_setting_MSG Setting up your own MSG code
264 Do not build your simulator by modifying the SimGrid examples. Go
265 outside the SimGrid source tree and create your own working directory
266 (say <tt>/home/joe/SimGrid/MyFirstScheduler/</tt>).
268 Suppose your simulation has the following structure (remember it is
269 just an example to illustrate a possible way to compile everything;
270 feel free to organize it as you want).
272 \li <tt>sched.h</tt>: a description of the core of the
273 scheduler (i.e. which functions are can be used by the
274 agents). For example we could find the following functions
275 (master, forwarder, slave).
277 \li <tt>sched.c</tt>: a C file including <tt>sched.h</tt> and
278 implementing the core of the scheduler. Most of these
279 functions use the MSG functions defined in section \ref
282 \li <tt>masterslave.c</tt>: a C file with the main function, i.e.
283 the MSG initialization (MSG_global_init()), the platform
284 creation (e.g. with MSG_create_environment()), the
285 deployment phase (e.g. with MSG_function_register() and
286 MSG_launch_application()) and the call to
289 To compile such a program, we suggest to use the following
290 Makefile. It is a generic Makefile that we have used many times with
291 our students when we teach the C language.
295 masterslave: masterslave.o sched.o
297 INSTALL_PATH = $$HOME
299 PEDANTIC_PARANOID_FREAK = -O0 -Wshadow -Wcast-align \
300 -Waggregate-return -Wmissing-prototypes -Wmissing-declarations \
301 -Wstrict-prototypes -Wmissing-prototypes -Wmissing-declarations \
302 -Wmissing-noreturn -Wredundant-decls -Wnested-externs \
303 -Wpointer-arith -Wwrite-strings -finline-functions
304 REASONABLY_CAREFUL_DUDE = -Wall
305 NO_PRAYER_FOR_THE_WICKED = -w -O2
306 WARNINGS = $(REASONABLY_CAREFUL_DUDE)
307 CFLAGS = -g $(WARNINGS)
309 INCLUDES = -I$(INSTALL_PATH)/include
310 DEFS = -L$(INSTALL_PATH)/lib/
311 LDADD = -lm -lsimgrid
315 $(CC) $(INCLUDES) $(DEFS) $(CFLAGS) $^ $(LIBS) $(LDADD) -o $@
318 $(CC) $(INCLUDES) $(DEFS) $(CFLAGS) -c -o $@ $<
321 rm -f $(BIN_FILES) *.o *~
327 The first two lines indicates what should be build when typing make
328 (<tt>masterslave</tt>) and of which files it is to be made of
329 (<tt>masterslave.o</tt> and <tt>sched.o</tt>). This makefile assumes
330 that you have set up correctly your <tt>LD_LIBRARY_PATH</tt> variable
331 (look, there is a <tt>LDADD = -lm -lsimgrid</tt>). If you prefer using
332 the static version, remove the <tt>-lsimgrid</tt> and add a
333 <tt>$(INSTALL_PATH)/lib/libsimgrid.a</tt> on the next line, right
334 after the <tt>LIBS = </tt>.
336 More generally, if you have never written a Makefile by yourself, type
337 in a terminal : <tt>info make</tt> and read the introduction. The
338 previous example should be enough for a first try but you may want to
339 perform some more complex compilations...
341 \subsection faq_setting_GRAS Setting up your own GRAS code
343 If you use the GRAS interface instead of the MSG one, then previous section
344 is not the better source of information. Instead, you should check the GRAS
345 tutorial in general, and the \ref GRAS_tut_tour_setup in particular.
347 \section faq_cmake CMAKE
349 \subsection faq_intro Some generalitty
351 \subsubsection faq_intro1 What is Cmake?
353 CMake is a family of tools designed to build, test and package software. CMake is used to control the software compilation process using simple platform and compiler independent configuration files. CMake generates native makefiles and workspaces that can be used in the compiler environment of your choice. For more information see official web site <a href="http://www.cmake.org/">here</a>.
355 \subsubsection faq_intro2 Why cmake?
357 CMake permits to developers to compil projects on different plateform. Then many tools are embedded like ctest for making test, a link to cdash for vizualise results but also test coverage and bug reports.
359 \subsubsection faq_intro3 What cmake need?
361 CMake needs some prerequists like :
363 \li c, c++ and java compiler regards to developers
364 \li ccmake for graphical used of CMake
365 \li cmake <a href="http://www.cmake.org/cmake/resources/software.html">(download page)</a>
368 \li Visual C++ 2010 Express <a href="http://www.microsoft.com/express/Downloads/#2010-Visual-CPP">(download page)</a>
369 \li cmake <a href="http://www.cmake.org/cmake/resources/software.html">(download page)</a>
370 \li Set CC, CXX, INCLUDE, LIB and RC to environment variables.
372 SET --> CC TO --> C:\MicrosoftVisualStudio10\VC\bin\cl
373 --> CXX --> C:\MicrosoftVisualStudio10\VC\bin\cl
374 --> INCLUDE --> C:\MicrosoftVisualStudio10\VC\include;C:\Program Files\Microsoft SDKs\Windows\v7.OA\Include
375 --> LIB --> C:\MicrosoftVisualStudio10\VC\lib;C:\Program Files\Microsoft SDKs\Windows\v7.OA\Lib
376 --> RC --> C:\Program Files\Microsoft SDKs\Windows\v7.OA\bin\RC
378 \li Add to environment variable "Path" the path where to find nmake executable and some needed files.
381 ;C\MicrosoftVisualStudio10\VC\bin
382 ;C\MicrosoftVisualStudio10\Common7\IDE
383 ;C:\Program Files\Microsoft SDKs\Windows\v7.OA\bin
384 ;C:\Program Files\Microsoft SDKs\Windows\v7.OA\Lib
385 ;C:\Program Files\Microsoft SDKs\Windows\v7.OA\bInclude
387 \subsection faq_cmakeoption Cmake options
389 \subsubsection faq_cmakeoption1 Liste of options
392 "cmake -D[name]=[value] ... ./"
394 [name] enable_gtnets [value] ON/OFF or TRUE/FALSE or 1/0
395 enable_java ON/OFF or TRUE/FALSE or 1/0
396 enable_lua ON/OFF or TRUE/FALSE or 1/0
397 enable_ruby ON/OFF or TRUE/FALSE or 1/0
398 enable_compile_optimizations ON/OFF or TRUE/FALSE or 1/0
399 enable_compile_warnings ON/OFF or TRUE/FALSE or 1/0
400 enable_smpi ON/OFF or TRUE/FALSE or 1/0
401 enable_maintainer_mode ON/OFF or TRUE/FALSE or 1/0
402 enable_supernovae ON/OFF or TRUE/FALSE or 1/0
403 enable_tracing ON/OFF or TRUE/FALSE or 1/0
404 enable_coverage ON/OFF or TRUE/FALSE or 1/0
405 enable_memcheck ON/OFF or TRUE/FALSE or 1/0
406 enable_model-checking ON/OFF or TRUE/FALSE or 1/0
408 gtnets_path <path_to_gtnets_directory>
409 prefix <path_to_install_directory>
410 BIBTEX2HTML <path_to_bibtex2html>
411 with_context auto/ucontext/pthread/window
414 \subsubsection faq_cmakeoption2 Options explaination
416 \li enable_gtnets : set to true implie that user wants to use gtnets.
418 \li enable_java : set to true implie that user wants to add java langage into simgrid compilation.
420 \li enable_lua : set to true implie that user wants to add lua langage into simgrid compilation.
422 \li enable_ruby : set to true implie that user wants to add ruby langage into simgrid compilation.
424 \li enable_compile_optimizations : add flags "-O3 -finline-functions -funroll-loops -fno-strict-aliasing"
426 \li enable_compile_warnings : add flags "-Wall -Wunused -Wmissing-prototypes -Wmissing-declarations -Wpointer-arith -Wchar-subscripts -Wcomment -Wformat -Wwrite-strings -Wno-unused-function -Wno-unused-parameter -Wno-strict-aliasing -Wno-format-nonliteral -Werror"
428 \li enable_smpi : Set to true if you want to use smpi lib. Actually on simgrid v3.4.1 Mac doesn't support lib smpi.
430 \li enable_maintainer_mode : set to true it remakes some files.
432 include/surf/simgrid_dtd.h
433 include/xbt/graphxml.h
442 src/xbt_strbuff_unit.c
445 src/xbt_synchro_unit.c
446 src/simgrid_units_main.c
452 src/surf/simgrid_dtd.c
453 src/surf/simgrid_dtd.l
458 src/gras/DataDesc/ddt_parse.yy.c
460 \li enable_supernovae : set to true make one file for each lib and compile with those generated files.
463 /src/supernovae_gras.c
464 /src/supernovae_smpi.c
467 \li enable_tracing : To enable the generation of simulation traces for visualization
469 \li enable_coverage : When set to true this option enable code coverage by setting -fprofile-arcs -ftest-coverage flags.
471 \li enable_memcheck : When set to true this option enable tests for memcheck.
473 \li enable_model-checking : Enable the model checking when set to true.
475 \li gtnets_path : Path to gtnets install directory (ex /usr)
477 \li prefix : Path where are installed lib/ doc/ and include/ directories (ex /usr/local)
479 \li BIBTEX2HTML : Path where is installed bibtex2html.
481 \li with context : specify which context the user wants to use.
483 \subsubsection faq_cmakeoption3 Initialisation
485 Those options are initialized the first time you launch "cmake ." whithout specified option.
492 enable_compile_optimizations off
493 enable_compile_warnings off
495 enable_maintainer_mode off
496 enable_supernovae off
500 enable_model-checking off
508 \subsubsection faq_cmakeoption4 Option's cache and how to reset?
510 When options have been set they are keep into a cache file named "CMakeCache.txt". So if you want
511 reset values you just delete this file located to the project directory.
513 \subsection faq_cmakecompilation Cmake compilation
515 \subsubsection faq_cmakecompilation1 With command line.
518 cmake -D[name]=[value] ... ./
522 \subsubsection faq_cmakecompilation2 With ccmake tool.
527 Then follow instructions.
529 \subsubsection faq_cmakecompilation2bis Build out of source.
531 As cmake generate many files used for compilation, we recommand to make a build directory.
532 For examples you can make :
535 "navarrop@caraja:~/Developments$ cd simgrid/"
536 "navarrop@caraja:~/Developments/simgrid$ mkdir build_directory"
537 "navarrop@caraja:~/Developments/simgrid$ cd build_directory/"
538 "navarrop@caraja:~/Developments/simgrid/build_directory$ cmake ../"
539 "navarrop@caraja:~/Developments/simgrid/build_directory$ make"
542 Or complety out of sources :
545 "navarrop@caraja:~/Developments$ mkdir build_dir"
546 "navarrop@caraja:~/Developments$ cd build_dir/"
547 "navarrop@caraja:~/Developments/build_dir$ cmake ../simgrid/"
548 "navarrop@caraja:~/Developments/build_dir$ make"
551 Those two kind of compilation permit to delete files created by compilation easier.
553 \subsubsection faq_cmakecompilation3 Resume of command line
557 cmake <path> configure the project
558 make build all targets
559 make VERBOSE=1 build all targets and print build command lines
560 make check test all targets and summarize
561 make dist make the distrib
562 make distcheck check the dist (make + make dist + make check)
563 make install install the project (doc/ lib/ include/)
564 make uninstall uninstall the project (doc/ lib/ include/)
565 make clean clean all targets
566 make java-clean clean files created by java option
567 make doc-clean clean files created for making doc
568 make supernovae-clean clean supernovae files
569 make maintainer-clean clean maintainer files
570 make all-clean execute the 5 upper clean command
571 make html Create simgrid documentation
574 When the project have been succesfully compiling and build you can make tests.
578 ctest launch only tests
580 ctest -D Continuous(Start|Update|Configure|Build)
581 ctest -D Continuous(Test|Coverage|MemCheck|Submit)
582 ctest -D Experimental
583 ctest -D Experimental(Start|Update|Configure|Build)
584 ctest -D Experimental(Test|Coverage|MemCheck|Submit)
586 ctest -D Nightly(Start|Update|Configure|Build)
587 ctest -D Nightly(Test|Coverage|MemCheck|Submit)
588 ctest -D NightlyMemoryCheck
591 If you want to test before make a commit you can simply make "ctest -D Experimental" and then you can visualize results submitted into Cdash. <a href="http://cdash.inria.fr/CDash/index.php?project=Simgrid">(Go to Cdash site)</a>.
593 \subsubsection faq_cmakecompilation4 Examples for different mode.
597 cmake -Denable_maintainer_mode=on ./
599 -- lookign for config.h
600 with_context auto change to ucontext
601 GIT_DATE : 2010-05-04~09-59-15
602 GIT_VERSION : 53ec816
603 GIT_SVN_VERSION : 7669
605 Configuration of package `simgrid' (revision 7669) on arch (=4):
607 SITE : Linux_2.6.31-21-generic_x86_64
608 Release : simgrid-3.4~rev7669
610 Compiler: c++ : /usr/bin/c++
611 version: c++ (Ubuntu 4.4.1-4ubuntu9) 4.4.1
612 Compiler: c : /usr/bin/gcc
613 version: gcc (Ubuntu 4.4.1-4ubuntu9) 4.4.1
615 CFlags : -I/usr/lib/ruby/1.8/x86_64-linux -I/usr/include/lua5.1 -g3
617 LDFlags : -L/usr/lib/
619 Context backend: ucontext
631 Simgrid dependencies: -lm -lruby1.8 -module -ldl -llua5.1 -lrt
632 Gras dependencies : -lm -lpthread -lrt
635 INSTALL_PREFIX: /usr/local
639 -- Build files have been written to: /home/navarrop/Developments/simgrid
644 cmake -Dsupernovae=on ./
646 -- lookign for config.h
647 with_context auto change to ucontext
648 GIT_DATE : 2010-05-04~09-59-15
649 GIT_VERSION : 53ec816
650 GIT_SVN_VERSION : 7669
652 Configuration of package `simgrid' (revision 7669) on arch (=4):
653 BUILDNAME : SUPERNOVAE
654 SITE : Linux_2.6.31-21-generic_x86_64
655 Release : simgrid-3.4~rev7669
657 Compiler: c++ : /usr/bin/c++
658 version: c++ (Ubuntu 4.4.1-4ubuntu9) 4.4.1
659 Compiler: c : /usr/bin/gcc
660 version: gcc (Ubuntu 4.4.1-4ubuntu9) 4.4.1
662 CFlags : -O3 -finline-functions -funroll-loops -fno-strict-aliasing -Wall -Wunused -Wmissing-prototypes -Wmissing-declarations -Wpointer-arith -Wchar-subscripts -Wcomment -Wformat -Wwrite-strings -Wno-unused-function -Wno-unused-parameter -Wno-strict-aliasing -Wno-format-nonliteral -Werror -I/usr/lib/ruby/1.8/x86_64-linux -I/usr/include/lua5.1 -g3
664 LDFlags : -L/usr/lib/
666 Context backend: ucontext
678 Simgrid dependencies: -lm -lruby1.8 -module -ldl -llua5.1 -lrt
679 Gras dependencies : -lm -lpthread -lrt
682 INSTALL_PREFIX: /usr/local
686 -- Build files have been written to: /home/navarrop/Developments/simgrid
692 cmake -Dgtnets_path=/home/navarrop/Bureau/usr/ ./
694 -- lookign for config.h
695 with_context auto change to ucontext
696 GIT_DATE : 2010-05-04~09-59-15
697 GIT_VERSION : 53ec816
698 GIT_SVN_VERSION : 7669
700 Configuration of package `simgrid' (revision 7669) on arch (=4):
702 SITE : Linux_2.6.31-21-generic_x86_64
703 Release : simgrid-3.4~rev7669
705 Compiler: c++ : /usr/bin/c++
706 version: c++ (Ubuntu 4.4.1-4ubuntu9) 4.4.1
707 Compiler: c : /usr/bin/gcc
708 version: gcc (Ubuntu 4.4.1-4ubuntu9) 4.4.1
710 CFlags : -O3 -finline-functions -funroll-loops -fno-strict-aliasing -Wall -Wunused -Wmissing-prototypes -Wmissing-declarations -Wpointer-arith -Wchar-subscripts -Wcomment -Wformat -Wwrite-strings -Wno-unused-function -Wno-unused-parameter -Wno-strict-aliasing -Wno-format-nonliteral -Werror -I/usr/lib/ruby/1.8/x86_64-linux -L/usr/lib -I/usr/include/gtnets -I/usr/include/lua5.1 -g3
711 CPPFlags: -L/usr/lib -I/usr/include/gtnets
712 LDFlags : -L/usr/lib/
714 Context backend: ucontext
726 Simgrid dependencies: -lm -lruby1.8 -module -ldl -llua5.1 -lgtnets -lrt
727 Gras dependencies : -lm -lpthread -lrt
730 INSTALL_PREFIX: /usr/local
734 -- Build files have been written to: /home/navarrop/Developments/simgrid
738 \subsection faq_cmakeinstall How to install with cmake?
740 \subsubsection faq_cmakeinstall1 From svn.
743 cmake -Denable_maintainer_mode=on -Dprefix=/home/navarrop/Bureau/install_simgrid ./
748 \subsubsection faq_cmakeinstall2 From a distrib
751 cmake -Dprefix=/home/navarrop/Bureau/install_simgrid ./
756 \subsection faq_cmakehowto How to modified sources files for developers
758 \subsubsection faq_cmakehowto1 Add an executable or examples.
760 If you want make an executable you have to create a CMakeList.txt to the src directory.
761 You must specified where to create the executable, source list, dependencies and the name of the binary.
764 cmake_minimum_required(VERSION 2.6)
766 set(EXECUTABLE_OUTPUT_PATH "./")
767 set(LIBRARY_OUTPUT_PATH "${PROJECT_DIRECTORY}/lib")
769 add_executable(get_sender get_sender.c) #add_executable(<name_of_target> <src list>)
771 ### Add definitions for compile
772 target_link_libraries(get_sender simgrid m pthread -fprofile-arcs) #target_link_libraries(<name_of_targe> <dependencies>)
775 Then you have to modified <project/directory>/buildtools/Cmake/CMakeMakeExeLib.txt and add
778 add_subdirectory(${PROJECT_DIRECTORY}/<path_where_is_CMakeList.txt>)
781 \subsubsection faq_cmakehowto2 Delete/add sources to lib.
783 If you want modified, add or delete source files from a library you have to edit <project/directory>/buildtools/Cmake/CMakeDefinePackages.txt
787 ${PROJECT_DIRECTORY}/src/java/simgrid/msg/MsgException.java
788 ${PROJECT_DIRECTORY}/src/java/simgrid/msg/JniException.java
789 ${PROJECT_DIRECTORY}/src/java/simgrid/msg/NativeException.java
790 ${PROJECT_DIRECTORY}/src/java/simgrid/msg/HostNotFoundException.java
791 ${PROJECT_DIRECTORY}/src/java/simgrid/msg/ProcessNotFoundException.java
792 ${PROJECT_DIRECTORY}/src/java/simgrid/msg/Msg.java
793 ${PROJECT_DIRECTORY}/src/java/simgrid/msg/Process.java
794 ${PROJECT_DIRECTORY}/src/java/simgrid/msg/Host.java
795 ${PROJECT_DIRECTORY}/src/java/simgrid/msg/Task.java
796 ${PROJECT_DIRECTORY}/src/java/simgrid/msg/MsgNative.java
797 ${PROJECT_DIRECTORY}/src/java/simgrid/msg/ApplicationHandler.java
798 ${PROJECT_DIRECTORY}/src/java/simgrid/msg/Sem.java
802 \subsubsection faq_cmakehowto3 Add test
804 If you want modified, add or delete tests you have to edit <project/directory>/buildtools/Cmake/CMakeTest.txt
805 with this function : ADD_TEST(<name> <bin> <ARGS>)
808 add_test(test-simdag-1 ${PROJECT_DIRECTORY}/testsuite/simdag/sd_test --cfg=path:${PROJECT_DIRECTORY}/testsuite/simdag small_platform_variable.xml)
811 \subsection faq_cmakeExplain Explaination of sources files for cmake
815 Those files are the "main parts". One located at the project directory call all the cmake sources files. The others
816 are little projects called by the first for make examples.
818 \li CMakeCompleteInFiles.txt
820 Complete all .in files and define Variables for h files
824 This file make the html documentation.
826 \li CMakeMakeExeLib.txt
828 Here are callled all "CMakeLists.txt" for make executables and libraries.
830 \li CMakePrintArgs.txt
832 This file is called at the end of the build for summarize environment variables.
834 \li CMakeDefinePackages.txt
836 Here is defined sources packages for compiling libs.
840 Defined flags which are used for compiling sources.
842 \li CMakeSupernovae.txt
844 Here are made files for the supernovae mode.
848 Here is defined packages for install simgrid and make a distribution.
850 \li CMakeMaintainerMode.txt
852 Part where are generated source files for maintainer mode.
856 Here are defined options and initialized values.
860 All tests are listed.
862 \li CTestConfig.cmake
864 Properties which link tests with dashboard.
866 \subsection faq_cmakeList List of files added for cmake
868 Here is a list of files involved into cmake build (relative to project directory path) :
873 ./buildtools/Cmake/AddTests.cmake
874 ./buildtools/Cmake/CompleteInFiles.cmake
875 ./buildtools/Cmake/CTestConfig.cmake
876 ./buildtools/Cmake/DefinePackages.cmake
877 ./buildtools/Cmake/Distrib.cmake
878 ./buildtools/Cmake/Flags.cmake
879 ./buildtools/Cmake/GenerateDocs.cmake
880 ./buildtools/Cmake/MaintainerMode.cmake
881 ./buildtools/Cmake/MakeExeLib.cmake
882 ./buildtools/Cmake/MakeJava.cmake
883 ./buildtools/Cmake/Option.cmake
884 ./buildtools/Cmake/PrintArgs.cmake
885 ./buildtools/Cmake/Supernovae.cmake
887 CMakeLists for each binaries or examples:
890 ./teshsuite/gras/empty_main/CMakeLists.txt
891 ./teshsuite/gras/small_sleep/CMakeLists.txt
892 ./teshsuite/gras/datadesc/CMakeLists.txt
893 ./teshsuite/gras/msg_handle/CMakeLists.txt
894 ./teshsuite/simdag/CMakeLists.txt
895 ./teshsuite/simdag/partask/CMakeLists.txt
896 ./teshsuite/simdag/platforms/CMakeLists.txt
897 ./teshsuite/simdag/network/CMakeLists.txt
898 ./teshsuite/simdag/network/mxn/CMakeLists.txt
899 ./teshsuite/simdag/network/p2p/CMakeLists.txt
900 ./teshsuite/xbt/CMakeLists.txt
901 ./teshsuite/msg/CMakeLists.txt
902 ./tools/gras/CMakeLists.txt
903 ./tools/tesh/CMakeLists.txt
904 ./testsuite/simdag/CMakeLists.txt
905 ./testsuite/xbt/CMakeLists.txt
906 ./testsuite/surf/CMakeLists.txt
907 ./examples/gras/properties/CMakeLists.txt
908 ./examples/gras/ping/CMakeLists.txt
909 ./examples/gras/pmm/CMakeLists.txt
910 ./examples/gras/mmrpc/CMakeLists.txt
911 ./examples/gras/synchro/CMakeLists.txt
912 ./examples/gras/timer/CMakeLists.txt
913 ./examples/gras/mutual_exclusion/simple_token/CMakeLists.txt
914 ./examples/gras/spawn/CMakeLists.txt
915 ./examples/gras/chrono/CMakeLists.txt
916 ./examples/gras/rpc/CMakeLists.txt
917 ./examples/gras/all2all/CMakeLists.txt
918 ./examples/simdag/properties/CMakeLists.txt
919 ./examples/simdag/CMakeLists.txt
920 ./examples/simdag/metaxml/CMakeLists.txt
921 ./examples/simdag/dax/CMakeLists.txt
922 ./examples/smpi/CMakeLists.txt
923 ./examples/amok/bandwidth/CMakeLists.txt
924 ./examples/amok/saturate/CMakeLists.txt
925 ./examples/msg/priority/CMakeLists.txt
926 ./examples/msg/properties/CMakeLists.txt
927 ./examples/msg/migration/CMakeLists.txt
928 ./examples/msg/gtnets/CMakeLists.txt
929 ./examples/msg/parallel_task/CMakeLists.txt
930 ./examples/msg/trace/CMakeLists.txt
931 ./examples/msg/suspend/CMakeLists.txt
932 ./examples/msg/masterslave/CMakeLists.txt
933 ./examples/msg/actions/CMakeLists.txt
934 ./examples/msg/sendrecv/CMakeLists.txt
937 \section faq_howto Feature related questions
939 \subsection faq_MIA "Could you please add (your favorite feature here) to SimGrid?"
941 Here is the deal. The whole SimGrid project (MSG, SURF, GRAS, ...) is
942 meant to be kept as simple and generic as possible. We cannot add
943 functions for everybody's needs when these functions can easily be
944 built from the ones already in the API. Most of the time, it is
945 possible and when it was not possible we always have upgraded the API
946 accordingly. When somebody asks us a question like "How to do that?
947 Is there a function in the API to simply do this?", we're always glad
948 to answer and help. However if we don't need this code for our own
949 need, there is no chance we're going to write it... it's your job! :)
950 The counterpart to our answers is that once you come up with a neat
951 implementation of this feature (task duplication, RPC, thread
952 synchronization, ...), you should send it to us and we will be glad to
953 add it to the distribution. Thus, other people will take advantage of
954 it (and we don't have to answer this question again and again ;).
956 You'll find in this section a few "Missing In Action" features. Many
957 people have asked about it and we have given hints on how to simply do
958 it with MSG. Feel free to contribute...
960 \subsection faq_MIA_MSG MSG features
962 \subsubsection faq_MIA_examples I want some more complex MSG examples!
964 Many people have come to ask me a more complex example and each time,
965 they have realized afterward that the basics were in the previous three
968 Of course they have often been needing more complex functions like
969 MSG_process_suspend(), MSG_process_resume() and
970 MSG_process_isSuspended() (to perform synchronization), or
971 MSG_task_Iprobe() and MSG_process_sleep() (to avoid blocking
972 receptions), or even MSG_process_create() (to design asynchronous
973 communications or computations). But the examples are sufficient to
976 We know. We should add some more examples, but not really some more
977 complex ones... We should add some examples that illustrate some other
978 functionalists (like how to simply encode asynchronous
979 communications, RPC, process migrations, thread synchronization, ...)
980 and we will do it when we will have a little bit more time. We have
981 tried to document the examples so that they are understandable. Tell
982 us if something is not clear and once again feel free to participate!
985 \subsubsection faq_MIA_taskdup Missing in action: MSG Task duplication/replication
987 There is no task duplication in MSG. When you create a task, you can
988 process it or send it somewhere else. As soon as a process has sent
989 this task, he doesn't have this task anymore. It's gone. The receiver
990 process has got the task. However, you could decide upon receiving to
991 create a "copy" of a task but you have to handle by yourself the
992 semantic associated to this "duplication".
994 As we already told, we prefer keeping the API as simple as
995 possible. This kind of feature is rather easy to implement by users
996 and the semantic you associate really depends on people. Having a
997 *generic* task duplication mechanism is not that trivial (in
998 particular because of the data field). That is why I would recommand
999 that you write it by yourself even if I can give you advice on how to
1002 You have the following functions to get informations about a task:
1003 MSG_task_get_name(), MSG_task_get_compute_duration(),
1004 MSG_task_get_remaining_computation(), MSG_task_get_data_size(),
1005 and MSG_task_get_data().
1007 You could use a dictionary (#xbt_dict_t) of dynars (#xbt_dynar_t). If
1008 you still don't see how to do it, please come back to us...
1010 \subsubsection faq_MIA_asynchronous I want to do asynchronous communications in MSG
1012 Up until now, there is no asynchronous communications in MSG. However,
1013 you can create as many process as you want so you should be able to do
1014 whatever you want... I've written a queue module to help implementing
1015 some asynchronous communications at low cost (creating thousands of
1016 process only to handle communications may be problematic in term of
1017 performance at some point). I'll add it in the distribution asap.
1019 \subsubsection faq_MIA_thread_synchronization I need to synchronize my MSG processes
1021 You obviously cannot use pthread_mutexes of pthread_conds. The best
1022 thing would be to propose similar structures. Unfortunately, we
1023 haven't found time to do it yet. However you can try to play with
1024 MSG_process_suspend() and MSG_process_resume(). You can even do some
1025 synchronization with fake communications (using MSG_task_get(),
1026 MSG_task_put() and MSG_task_Iprobe()).
1028 \subsubsection faq_MIA_host_load Where is the get_host_load function hidden in MSG?
1030 There is no such thing because its semantic wouldn't be really
1031 clear. Of course, it is something about the amount of host throughput,
1032 but there is as many definition of "host load" as people asking for
1033 this function. First, you have to remember that resource availability
1034 may vary over time, which make any load notion harder to define.
1036 It may be instantaneous value or an average one. Moreover it may be only the
1037 power of the computer, or may take the background load into account, or may
1038 even take the currently running tasks into account. In some SURF models,
1039 communications have an influence on computational power. Should it be taken
1042 First of all, it's near to impossible to predict the load beforehands in the
1043 simulator since it depends on too much parameters (background load
1044 variation, bandwidth sharing algorithmic complexity) some of them even being
1045 not known beforehands (other task starting at the same time). So, getting
1046 this information is really hard (just like in real life). It's not just that
1047 we want MSG to be as painful as real life. But as it is in some way
1048 realistic, we face some of the same problems as we would face in real life.
1050 How would you do it for real? The most common option is to use something
1051 like NWS that performs active probes. The best solution is probably to do
1052 the same within MSG, as in next code snippet. It is very close from what you
1053 would have to do out of the simulator, and thus gives you information that
1054 you could also get in real settings to not hinder the realism of your
1058 double get_host_load() {
1059 m_task_t task = MSG_task_create("test", 0.001, 0, NULL);
1060 double date = MSG_get_clock();
1062 MSG_task_execute(task);
1063 date = MSG_get_clock() - date;
1064 MSG_task_destroy(task);
1065 return (0.001/date);
1069 Of course, it may not match your personal definition of "host load". In this
1070 case, please detail what you mean on the mailing list, and we will extend
1071 this FAQ section to fit your taste if possible.
1073 \subsubsection faq_MIA_communication_time How can I get the *real* communication time?
1075 Communications are synchronous and thus if you simply get the time
1076 before and after a communication, you'll only get the transmission
1077 time and the time spent to really communicate (it will also take into
1078 account the time spent waiting for the other party to be
1079 ready). However, getting the *real* communication time is not really
1080 hard either. The following solution is a good starting point.
1085 m_task_t task = MSG_task_create("Task", task_comp_size, task_comm_size,
1086 calloc(1,sizeof(double)));
1087 *((double*) task->data) = MSG_get_clock();
1088 MSG_task_put(task, slaves[i % slaves_count], PORT_22);
1089 INFO0("Send completed");
1094 m_task_t task = NULL;
1097 time1 = MSG_get_clock();
1098 a = MSG_task_get(&(task), PORT_22);
1099 time2 = MSG_get_clock();
1100 if(time1<*((double *)task->data))
1101 time1 = *((double *) task->data);
1102 INFO1("Communication time : \"%f\" ", time2-time1);
1104 MSG_task_destroy(task);
1109 \subsection faq_MIA_SimDag SimDag related questions
1111 \subsubsection faq_SG_comm Implementing communication delays between tasks.
1113 A classic question of SimDag newcomers is about how to express a
1114 communication delay between tasks. The thing is that in SimDag, both
1115 computation and communication are seen as tasks. So, if you want to
1116 model a data dependency between two DAG tasks t1 and t2, you have to
1117 create 3 SD_tasks: t1, t2 and c and add dependencies in the following
1121 SD_task_dependency_add(NULL, NULL, t1, c);
1122 SD_task_dependency_add(NULL, NULL, c, t2);
1125 This way task t2 cannot start before the termination of communication c
1126 which in turn cannot start before t1 ends.
1128 When creating task c, you have to associate an amount of data (in bytes)
1129 corresponding to what has to be sent by t1 to t2.
1131 Finally to schedule the communication task c, you have to build a list
1132 comprising the workstations on which t1 and t2 are scheduled (w1 and w2
1133 for example) and build a communication matrix that should look like
1136 \subsubsection faq_SG_DAG How to implement a distributed dynamic scheduler of DAGs.
1138 Distributed is somehow "contagious". If you start making distributed
1139 decisions, there is no way to handle DAGs directly anymore (unless I
1140 am missing something). You have to encode your DAGs in term of
1141 communicating process to make the whole scheduling process
1142 distributed. Here is an example of how you could do that. Assume T1
1143 has to be done before T2.
1146 int your_agent(int argc, char *argv[] {
1148 T1 = MSG_task_create(...);
1149 T2 = MSG_task_create(...);
1153 if(cond) MSG_task_execute(T1);
1155 if((MSG_task_get_remaining_computation(T1)=0.0) && (you_re_in_a_good_mood))
1156 MSG_task_execute(T2)
1158 /* do something else */
1164 If you decide that the distributed part is not that much important and that
1165 DAG is really the level of abstraction you want to work with, then you should
1166 give a try to \ref SD_API.
1168 \subsection faq_MIA_generic Generic features
1170 \subsubsection faq_more_processes Increasing the amount of simulated processes
1172 Here are a few tricks you can apply if you want to increase the amount
1173 of processes in your simulations.
1175 - <b>A few thousands of simulated processes</b> (soft tricks)\n
1176 SimGrid can use either pthreads library or the UNIX98 contextes. On
1177 most systems, the number of pthreads is limited and then your
1178 simulation may be limited for a stupid reason. This is especially
1179 true with the current linux pthreads, and I cannot get more than
1180 2000 simulated processes with pthreads on my box. The UNIX98
1181 contexts allow me to raise the limit to 25,000 simulated processes
1183 The <tt>--with-context</tt> option of the <tt>./configure</tt>
1184 script allows you to choose between UNIX98 contextes
1185 (<tt>--with-context=ucontext</tt>) and the pthread version
1186 (<tt>--with-context=pthread</tt>). The default value is ucontext
1187 when the script detect a working UNIX98 context implementation. On
1188 Windows boxes, the provided value is discarded and an adapted
1189 version is picked up.\n\n
1190 We experienced some issues with contextes on some rare systems
1191 (solaris 8 and lower or old alpha linuxes comes to mind). The main
1192 problem is that the configure script detect the contextes as being
1193 functional when it's not true. If you happen to use such a system,
1194 switch manually to the pthread version, and provide us with a good
1195 patch for the configure script so that it is done automatically ;)
1197 - <b>Hundred thousands of simulated processes</b> (hard-core tricks)\n
1198 As explained above, SimGrid can use UNIX98 contextes to represent
1199 and handle the simulated processes. Thanks to this, the main
1200 limitation to the number of simulated processes becomes the
1201 available memory.\n\n
1202 Here are some tricks I had to use in order to run a token ring
1203 between 25,000 processes on my laptop (1Gb memory, 1.5Gb swap).\n
1204 - First of all, make sure your code runs for a few hundreds
1205 processes before trying to push the limit. Make sure it's
1206 valgrind-clean, ie that valgrind does not report neither memory
1207 error nor memory leaks. Indeed, numerous simulated processes
1208 result in *fat* simulation hindering debugging.
1209 - It was really boring to write 25,000 entries in the deployment
1210 file, so I wrote a little script
1211 <tt>examples/gras/mutual_exclusion/simple_token/make_deployment.pl</tt>, which you may
1212 want to adapt to your case. You could also think about hijacking
1213 the SURFXML parser (have look at \ref faq_flexml_bypassing).
1214 - The deployment file became quite big, so I had to do what is in
1215 the FAQ entry \ref faq_flexml_limit
1216 - Each UNIX98 context has its own stack entry. As debugging this is
1217 quite hairly, the default value is a bit overestimated so that
1218 user don't get into trouble about this. You want to tune this
1219 size to increse the number of processes. This is the
1220 <tt>STACK_SIZE</tt> define in
1221 <tt>src/xbt/xbt_context_sysv.c</tt>, which is 128kb by default.
1222 Reduce this as much as you can, but be warned that if this value
1223 is too low, you'll get a segfault. The token ring example, which
1224 is quite simple, runs with 40kb stacks.
1225 - You may tweak the logs to reduce the stack size further. When
1226 logging something, we try to build the string to display in a
1227 char array on the stack. The size of this array is constant (and
1228 equal to XBT_LOG_BUFF_SIZE, defined in include/xbt/log/h). If the
1229 string is too large to fit this buffer, we move to a dynamically
1230 sized buffer. In which case, we have to traverse one time the log
1231 event arguments to compute the size we need for the buffer,
1232 malloc it, and traverse the argument list again to do the actual
1234 The idea here is to move XBT_LOG_BUFF_SIZE to 1, forcing the logs
1235 to use a dynamic array each time. This allows us to lower further
1236 the stack size at the price of some performance loss...\n
1237 This allowed me to run the reduce the stack size to ... 4k. Ie,
1238 on my 1Gb laptop, I can run more than 250,000 processes!
1240 \subsubsection faq_MIA_batch_scheduler Is there a native support for batch schedulers in SimGrid?
1242 No, there is no native support for batch schedulers and none is
1243 planned because this is a very specific need (and doing it in a
1244 generic way is thus very hard). However some people have implemented
1245 their own batch schedulers. Vincent Garonne wrote one during his PhD
1246 and put his code in the contrib directory of our SVN so that other can
1247 keep working on it. You may find inspiring ideas in it.
1249 \subsubsection faq_MIA_checkpointing I need a checkpointing thing
1251 Actually, it depends on whether you want to checkpoint the simulation, or to
1252 simulate checkpoints.
1254 The first one could help if your simulation is a long standing process you
1255 want to keep running even on hardware issues. It could also help to
1256 <i>rewind</i> the simulation by jumping sometimes on an old checkpoint to
1257 cancel recent calculations.\n
1258 Unfortunately, such thing will probably never exist in SG. One would have to
1259 duplicate all data structures because doing a rewind at the simulator level
1260 is very very hard (not talking about the malloc free operations that might
1261 have been done in between). Instead, you may be interested in the Libckpt
1262 library (http://www.cs.utk.edu/~plank/plank/www/libckpt.html). This is the
1263 checkpointing solution used in the condor project, for example. It makes it
1264 easy to create checkpoints (at the OS level, creating something like core
1265 files), and rerunning them on need.
1267 If you want to simulate checkpoints instead, it means that you want the
1268 state of an executing task (in particular, the progress made towards
1269 completion) to be saved somewhere. So if a host (and the task executing on
1270 it) fails (cf. #MSG_HOST_FAILURE), then the task can be restarted
1271 from the last checkpoint.\n
1273 Actually, such a thing does not exists in SimGrid either, but it's just
1274 because we don't think it is fundamental and it may be done in the user code
1275 at relatively low cost. You could for example use a watcher that
1276 periodically get the remaining amount of things to do (using
1277 MSG_task_get_remaining_computation()), or fragment the task in smaller
1280 \subsection faq_platform Platform building and Dynamic resources
1282 \subsubsection faq_platform_example Where can I find SimGrid platform files?
1284 There is several little examples in the archive, in the examples/msg
1285 directory. From time to time, we are asked for other files, but we
1286 don't have much at hand right now.
1288 You should refer to the Platform Description Archive
1289 (http://pda.gforge.inria.fr) project to see the other platform file we
1290 have available, as well as the Simulacrum simulator, meant to generate
1291 SimGrid platforms using all classical generation algorithms.
1293 \subsubsection faq_platform_alnem How can I automatically map an existing platform?
1295 We are working on a project called ALNeM (Application-Level Network
1296 Mapper) which goal is to automatically discover the topology of an
1297 existing network. Its output will be a platform description file
1298 following the SimGrid syntax, so everybody will get the ability to map
1299 their own lab network (and contribute them to the catalog project).
1300 This tool is not ready yet, but it move quite fast forward. Just stay
1303 \subsubsection faq_platform_synthetic Generating synthetic but realistic platforms
1305 The third possibility to get a platform file (after manual or
1306 automatic mapping of real platforms) is to generate synthetic
1307 platforms. Getting a realistic result is not a trivial task, and
1308 moreover, nobody is really able to define what "realistic" means when
1309 speaking of topology files. You can find some more thoughts on this
1311 <a href="http://graal.ens-lyon.fr/~alegrand/articles/Simgrid-Introduction.pdf">slides</a>.
1313 If you are looking for an actual tool, there we have a little tool to
1314 annotate Tiers-generated topologies. This perl-script is in
1315 <tt>tools/platform_generation/</tt> directory of the SVN. Dinda et Al.
1316 released a very comparable tool, and called it GridG.
1318 \subsubsection faq_SURF_dynamic Expressing dynamic resource availability in platform files
1320 A nice feature of SimGrid is that it enables you to seamlessly have
1321 resources whose availability change over time. When you build a
1322 platform, you generally declare hosts like that:
1325 <host id="host A" power="100.00"/>
1328 If you want the availability of "host A" to change over time, the only
1329 thing you have to do is change this definition like that:
1332 <host id="host A" power="100.00" availability_file="trace_A.txt" state_file="trace_A_failure.txt"/>
1335 For hosts, availability files are expressed in fraction of available
1336 power. Let's have a look at what "trace_A.txt" may look like:
1345 At time 0, our host will deliver 100 flop/s. At time 11.0, it will
1346 deliver only 50 flop/s until time 20.0 where it will will start
1347 delivering 90 flop/s. Last at time 21.0 (20.0 plus the periodicity
1348 1.0), we'll be back to the beginning and it will deliver 100 flop/s.
1350 Now let's look at the state file:
1357 A negative value means "off" while a positive one means "on". At time
1358 1.0, the host is on. At time 1.0, it is turned off and at time 2.0, it
1359 is turned on again until time 12 (2.0 plus the periodicity 10.0). It
1360 will be turned on again at time 13.0 until time 23.0, and so on.
1362 Now, let's look how the same kind of thing can be done for network
1363 links. A usual declaration looks like:
1366 <link id="LinkA" bandwidth="10.0" latency="0.2"/>
1369 You have at your disposal the following options: bandwidth_file,
1370 latency_file and state_file. The only difference with hosts is that
1371 bandwidth_file and latency_file do not express fraction of available
1372 power but are expressed directly in bytes per seconds and seconds.
1374 \subsubsection faq_platform_multipath How to express multipath routing in platform files?
1376 It is unfortunately impossible to express the fact that there is more
1377 than one routing path between two given hosts. Let's consider the
1378 following platform file:
1381 <route src="A" dst="B">
1384 <route src="B" dst="C">
1387 <route src="A" dst="C">
1392 Although it is perfectly valid, it does not mean that data traveling
1393 from A to C can either go directly (using link 3) or through B (using
1394 links 1 and 2). It simply means that the routing on the graph is not
1395 trivial, and that data do not following the shortest path in number of
1396 hops on this graph. Another way to say it is that there is no implicit
1397 in these routing descriptions. The system will only use the routes you
1398 declare (such as <route src="A" dst="C"><link:ctn
1399 id="3"/></route>), without trying to build new routes by aggregating
1402 You are also free to declare platform where the routing is not
1403 symmetric. For example, add the following to the previous file:
1406 <route src="C" dst="A">
1412 This makes sure that data from C to A go through B where data from A
1413 to C go directly. Don't worry about realism of such settings since
1414 we've seen ways more weird situation in real settings (in fact, that's
1415 the realism of very regular platforms which is questionable, but
1416 that's another story).
1418 \subsubsection faq_flexml_bypassing Bypassing the XML parser with your own C functions
1420 So you want to bypass the XML files parser, uh? Maybe doing some parameter
1421 sweep experiments on your simulations or so? This is possible, and
1422 it's not even really difficult (well. Such a brutal idea could be
1423 harder to implement). Here is how it goes.
1425 For this, you have to first remember that the XML parsing in SimGrid is done
1426 using a tool called FleXML. Given a DTD, this gives a flex-based parser. If
1427 you want to bypass the parser, you need to provide some code mimicking what
1428 it does and replacing it in its interactions with the SURF code. So, let's
1429 have a look at these interactions.
1431 FleXML parser are close to classical SAX parsers. It means that a
1432 well-formed SimGrid platform XML file might result in the following
1435 - start "platform_description" with attribute version="2"
1436 - start "host" with attributes id="host1" power="1.0"
1438 - start "host" with attributes id="host2" power="2.0"
1440 - start "link" with ...
1442 - start "route" with ...
1443 - start "link:ctn" with ...
1446 - end "platform_description"
1448 The communication from the parser to the SURF code uses two means:
1449 Attributes get copied into some global variables, and a surf-provided
1450 function gets called by the parser for each event. For example, the event
1451 - start "host" with attributes id="host1" power="1.0"
1453 let the parser do something roughly equivalent to:
1455 strcpy(A_host_id,"host1");
1460 In SURF, we attach callbacks to the different events by initializing the
1461 pointer functions to some the right surf functions. Since there can be
1462 more than one callback attached to the same event (if more than one
1463 model is in use, for example), they are stored in a dynar. Example in
1464 workstation_ptask_L07.c:
1466 /* Adding callback functions */
1467 surf_parse_reset_parser();
1468 surfxml_add_callback(STag_surfxml_host_cb_list, &parse_cpu_init);
1469 surfxml_add_callback(STag_surfxml_prop_cb_list, &parse_properties);
1470 surfxml_add_callback(STag_surfxml_link_cb_list, &parse_link_init);
1471 surfxml_add_callback(STag_surfxml_route_cb_list, &parse_route_set_endpoints);
1472 surfxml_add_callback(ETag_surfxml_link_c_ctn_cb_list, &parse_route_elem);
1473 surfxml_add_callback(ETag_surfxml_route_cb_list, &parse_route_set_route);
1475 /* Parse the file */
1476 surf_parse_open(file);
1477 xbt_assert1((!surf_parse()), "Parse error in %s", file);
1481 So, to bypass the FleXML parser, you need to write your own version of the
1482 surf_parse function, which should do the following:
1483 - Fill the A_<tag>_<attribute> variables with the wanted values
1484 - Call the corresponding STag_<tag>_fun function to simulate tag start
1485 - Call the corresponding ETag_<tag>_fun function to simulate tag end
1486 - (do the same for the next set of values, and loop)
1488 Then, tell SimGrid that you want to use your own "parser" instead of the stock one:
1490 surf_parse = surf_parse_bypass_environment;
1491 MSG_create_environment(NULL);
1492 surf_parse = surf_parse_bypass_application;
1493 MSG_launch_application(NULL);
1496 A set of macros are provided at the end of
1497 include/surf/surfxml_parse.h to ease the writing of the bypass
1498 functions. An example of this trick is distributed in the file
1499 examples/msg/masterslave/masterslave_bypass.c
1501 \subsection faq_simgrid_configuration Changing SimGrid's behavior
1503 A number of options can be given at runtime to change the default
1504 SimGrid behavior. In particular, you can change the default cpu and
1507 \subsubsection faq_simgrid_configuration_gtnets Using GTNetS
1509 It is possible to use a packet-level network simulator
1510 instead of the default flow-based simulation. You may want to use such
1511 an approach if you have doubts about the validity of the default model
1512 or if you want to perform some validation experiments. At the moment,
1513 we support the GTNetS simulator (it is still rather experimental
1514 though, so leave us a message if you play with it).
1518 To enable GTNetS model inside SimGrid it is needed to patch the GTNetS simulator source code
1519 and build/install it from scratch
1522 - <b>Download and enter the recent downloaded GTNetS directory</b>
1525 svn checkout svn://scm.gforge.inria.fr/svn/simgrid/contrib/trunk/GTNetS/
1530 - <b>Use the following commands to unzip and patch GTNetS package to work within SimGrid.</b>
1533 unzip gtnets-current.zip
1534 tar zxvf gtnets-current-patch.tgz
1536 cat ../00*.patch | patch -p1
1539 - <b>OPTIONALLY</b> you can use a patch for itanium 64bit processor family.
1542 cat ../AMD64-FATAL-Removed-DUL_SIZE_DIFF-Added-fPIC-compillin.patch | patch -p1
1545 - <b>Compile GTNetS</b>
1547 Due to portability issues it is possible that GTNetS does not compile in your architecture. The patches furnished in SimGrid SVN repository are intended for use in Linux architecture only. Unfortunately, we do not have the time, the money, neither the manpower to guarantee GTNetS portability. We advice you to use one of GTNetS communication channel to get more help in compiling GTNetS.
1551 ln -sf Makefile.linux Makefile
1557 - <b>NOTE</b> A lot of warnings are expected but the application should compile
1558 just fine. If the makefile insists in compiling some QT libraries
1559 please try a make clean before asking for help.
1562 - <b>To compile optimized version</b>
1569 - <b>Installing GTNetS</b>
1571 It is important to put the full path of your libgtsim-xxxx.so file when creating the symbolic link. Replace < userhome > by some path you have write access to.
1574 ln -sf /<absolute_path>/gtnets_current/libgtsim-debug.so /<userhome>/usr/lib/libgtnets.so
1575 export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/<userhome>/usr/lib/libgtnets.so
1576 mkdir /<userhome>/usr/include/gtnets
1577 cp -fr SRC/*.h /<userhome>/usr/include/gtnets
1581 - <b>Enable GTNetS support in SimGrid</b>
1584 ./configure --with-gtnets=/<userhome>/usr
1587 - <b>Once you have followed all the instructions for compiling and
1588 installing successfully you can activate this feature at
1589 runntime with the following options:</b>
1592 cd simgrid/example/msg/
1598 - <b>Or try the GTNetS model dogbone example with</b>
1601 gtnets/gtnets gtnets/onelink-p.xml gtnets/onelink-d.xml --cfg=network_model:GTNets
1605 A long version of this <a href="http://gforge.inria.fr/docman/view.php/12/6283/GTNetS HowTo.html">HowTo</a> it is available
1608 More about GTNetS simulator at <a href="http://www.ece.gatech.edu/research/labs/MANIACS/GTNetS/index.html">GTNetS Website</a>
1612 The patches provided by us worked successfully with GTNetS found
1613 <a href="http://www.ece.gatech.edu/research/labs/MANIACS/GTNetS/software/gtnets-current.zip">here</a>,
1614 dated from 12th June 2008. Due to the discontinuing development of
1615 GTNetS it is impossible to precise a version number. We STRONGLY recommend you
1616 to download and install the GTNetS version found in SimGrid repository as explained above.
1621 \subsubsection faq_simgrid_configuration_alternate_network Using alternative flow models
1623 The default simgrid network model uses a max-min based approach as
1624 explained in the research report
1625 <a href="ftp://ftp.ens-lyon.fr/pub/LIP/Rapports/RR/RR2002/RR2002-40.ps.gz">A Network Model for Simulation of Grid Application</a>.
1626 Other models have been proposed and implemented since then (see for example
1627 <a href="http://mescal.imag.fr/membres/arnaud.legrand/articles/simutools09.pdf">Accuracy Study and Improvement of Network Simulation in the SimGrid Framework</a>)
1628 and can be activated at runtime. For example:
1630 ./mycode platform.xml deployment.xml --cfg=workstation/model:compound --cfg=network/model:LV08 -cfg=cpu/model:Cas01
1633 Possible models for the network are currently "Constant", "CM02",
1634 "LegrandVelho", "GTNets", Reno", "Reno2", "Vegas". Others will
1635 probably be added in the future and many of the previous ones are
1636 experimental and are likely to disappear without notice... To know the
1637 list of the currently implemented models, you should use the
1638 --help-models command line option.
1641 ./masterslave_forwarder ../small_platform.xml deployment_masterslave.xml --help-models
1642 Long description of the workstation models accepted by this simulator:
1643 CLM03: Default workstation model, using LV08 and CM02 as network and CPU
1644 compound: Workstation model allowing you to use other network and CPU models
1645 ptask_L07: Workstation model with better parallel task modeling
1646 Long description of the CPU models accepted by this simulator:
1647 Cas01_fullupdate: CPU classical model time=size/power
1648 Cas01: Variation of Cas01_fullupdate with partial invalidation optimization of lmm system. Should produce the same values, only faster
1649 CpuTI: Variation of Cas01 with also trace integration. Should produce the same values, only faster if you use availability traces
1650 Long description of the network models accepted by this simulator:
1651 Constant: Simplistic network model where all communication take a constant time (one second)
1652 CM02: Realistic network model with lmm_solve and no correction factors
1653 LV08: Realistic network model with lmm_solve and these correction factors: latency*=10.4, bandwidth*=.92, S=8775
1654 Reno: Model using lagrange_solve instead of lmm_solve (experts only)
1655 Reno2: Model using lagrange_solve instead of lmm_solve (experts only)
1656 Vegas: Model using lagrange_solve instead of lmm_solve (experts only)
1659 \subsection faq_tracing Tracing Simulations for Visualization
1661 The trace visualization is widely used to observe and understand the behavior
1662 of parallel applications and distributed algorithms. Usually, this is done in a
1663 two-step fashion: the user instruments the application and the traces are
1664 analyzed after the end of the execution. The visualization itself can highlights
1665 unexpected behaviors, bottlenecks and sometimes can be used to correct
1666 distributed algorithms. The SimGrid team is currently instrumenting the library
1667 in order to let users trace their simulations and analyze them. This part of the
1668 user manual explains how the tracing-related features can be enabled and used
1669 during the development of simulators using the SimGrid library.
1671 \subsubsection faq_tracing_howitworks How it works
1673 For now, the SimGrid library is instrumented so users can trace the <b>platform
1674 utilization</b> using the MSG interface. This means that the tracing will
1675 register how much power is used for each host and how much bandwidth is used for
1676 each link of the platform. The idea with this type of tracing is to observe the
1677 overall view of resources utilization in the first place, especially the
1678 identification of bottlenecks, load-balancing among hosts, and so on.
1680 The idea of the instrumentation is to classify the MSG tasks by category,
1682 the platform utilization (hosts and links) for each of the categories. For that,
1683 the tracing interface enables the declaration of categories and a function to
1684 mark a task with a previously declared category. <em>The tasks that are not
1685 classified according to a category are not traced</em>.
1687 \subsubsection faq_tracing_enabling Enabling using CMake
1689 With the sources of SimGrid, it is possible to enable the tracing
1690 using the parameter <b>-Dtracing=on</b> when the cmake is executed.
1691 The section \ref faq_tracing_functions describes all the functions available
1692 when this Cmake options is activated. These functions will have no effect
1693 if SimGrid is configured without this option (they are wiped-out by the
1697 $ cmake -Dtracing=on .
1701 \subsubsection faq_tracing_functions Tracing Functions
1703 \subsubsubsection Mandatory Functions
1705 \li <b>\c TRACE_start (const char *filename)</b>: This is the first function to
1706 be called. It receives a single argument as parameter that contains the name of
1707 the file that will hold the trace in the end of the simulation. It returns 0 if
1708 everything was properly initialized, 1 otherwise. All trace functions called
1709 before TRACE_start do nothing.
1711 \li <b>\c TRACE_category (const char *category)</b>: This function should be used
1712 to define a user category. The category can be used to differentiate the tasks
1713 that are created during the simulation (for example, tasks from server1,
1714 server2, or request tasks, computation tasks, communication tasks).
1715 All resource utilization (host power and link bandwidth) will be
1716 classified according to the task category. Tasks that do not belong to a
1717 category are not traced.
1719 \li <b>\c TRACE_msg_set_task_category (m_task_t task, const char *category)</b>:
1720 This function should be called after the creation of a task, to define the
1721 category of that task. The first parameter \c task must contain a task that was
1722 created with the function \c MSG_task_create. The second parameter
1723 \c category must contain a category that was previously defined by the function
1726 \li <b>\c TRACE_end ()</b>: This is the last function to be called. It closes
1727 the trace file and stops the tracing of the simulation. All tracing will be
1728 completely disabled after the calling this function. Although we recommend
1729 the use of this function somewhere in the end of program, it can be used
1730 anywhere in the code. This function returns 0 if everything is ok, 1 otherwise.
1732 \subsubsubsection Optional Functions
1734 \li <b>\c TRACE_host_variable_declare (const char *variable)</b>:
1735 Declare a user variable that will be associated to hosts. A variable can
1736 be used to trace user variables such as the number of tasks in a server,
1737 the number of clients in an application, and so on.
1739 \li <b>\c TRACE_host_variable_[set|add|sub] (const char *variable, double
1741 Set the value of a given user variable. It is important to remind that
1742 the value of this variable is always associated to the host. The host
1743 that will be used when these functions are called is the one returned by
1744 the function \c MSG_host_self().
1746 \subsubsection faq_tracing_example Example of Instrumentation
1748 A simplified example using the tracing mandatory functions.
1751 int main (int argc, char **argv)
1753 TRACE_start ("traced_simulation.trace");
1754 TRACE_category ("request");
1755 TRACE_category ("computation");
1756 TRACE_category ("finalize");
1758 MSG_global_init (&argc, &argv);
1760 //(... after deployment ...)
1762 m_task_t req1 = MSG_task_create("1st_request_task", 10, 10, NULL);
1763 m_task_t req2 = MSG_task_create("2nd_request_task", 10, 10, NULL);
1764 m_task_t req3 = MSG_task_create("3rd_request_task", 10, 10, NULL);
1765 m_task_t req4 = MSG_task_create("4th_request_task", 10, 10, NULL);
1766 TRACE_msg_set_task_category (req1, "request");
1767 TRACE_msg_set_task_category (req2, "request");
1768 TRACE_msg_set_task_category (req3, "request");
1769 TRACE_msg_set_task_category (req4, "request");
1771 m_task_t comp = MSG_task_create ("comp_task", 100, 100, NULL);
1772 TRACE_msg_set_task_category (comp, "computation");
1774 m_task_t finalize = MSG_task_create ("finalize", 0, 0, NULL);
1775 TRACE_msg_set_task_category (finalize, "finalize");
1786 \subsubsection faq_tracing_analyzing Analyzing the SimGrid Traces
1788 The SimGrid library, during an instrumented simulation, creates a trace file in
1789 the Paje file format that contains the platform utilization for the simulation
1790 that was executed. The visualization analysis of this file is performed with the
1791 visualization tool <a href="http://triva.gforge.inria.fr">Triva</a>, with
1792 special configurations tunned to SimGrid needs. This part of the documentation
1793 explains how to configure and use Triva to analyse a SimGrid trace file.
1795 - <b>Installing Triva</b>: the tool is available in the INRIAGforge,
1796 at <a href="http://triva.gforge.inria.fr">http://triva.gforge.inria.fr</a>.
1797 Use the following command to get the sources, and then check the file
1798 <i>INSTALL.simplified</i>. This file contains instructions to install
1799 the tool's dependencies in a Ubuntu/Debian Linux.
1801 $ svn checkout svn://scm.gforge.inria.fr/svn/triva
1803 $ cat INSTALL.simplified
1806 - <b>Executing Triva</b>: a binary called <i>Triva</i> is available after the
1807 installation (you can execute it passing <em>--help</em> to check its
1808 options). If the triva binary is not available after following the
1809 installation instructions, you may want to execute the following command to
1810 initialize the GNUstep environment variables (note that the location of the
1811 <i>GNUstep.sh</i> file may vary depending on your GNUstep installation - the
1812 command is known to work in Ubuntu and Debian Linux):
1814 $ source /usr/share/GNUstep/Makefiles/GNUstep.sh
1816 You should be able to see this output after the installation of triva:
1818 $ ./Triva.app/Triva --help
1819 Usage: Triva [OPTION...] TRACEFILE
1820 Trace Analysis through Visualization
1822 You need to use one of the following options:
1823 -g, --graph Graph Analysis
1824 -t, --treemap Treemap Analysis
1826 Other auxiliary options to check the trace file:
1827 -c, --check Check the integrity of trace file
1828 -h, --hierarchy Export the trace type hierarchy
1829 -l, --list List entity types
1831 -?, --help Give this help list
1832 --usage Give a short usage message
1834 Triva expects that the user choose one of the available options
1835 (currently <em>--graph</em> or <em>--treemap</em> for a visualization analysis)
1836 and the trace file from the simulation.
1838 - <b>Understanding Triva - time-slice</b>: the analysis of a trace file using
1839 the tool always takes into account the concept of the <em>time-slice</em>.
1840 This concept means that what is being visualized in the screen is always
1841 calculated considering a specific time frame, with its beggining and end
1842 timestamp. The time-slice is configured by the user and can be changed
1843 dynamically through the window called <em>Time Interval</em> that is opened
1844 whenever a trace file is being analyzed. The next figure depicts the time-slice
1845 configuration window.
1846 In the top of the window, in the space named <i>Trace Time</i>,
1847 the two fields show the beggining of the trace (which usually starts in 0) and
1848 the end (that depends on the time simulated by SimGrid). The middle of the
1849 window, in the square named <i>Time Slice Configuration</i>, contains the
1850 aspects related to the time-slice, including its <i>start</i> and its
1851 <i>size</i>. The gray rectangle in the bottom of this part indicates the
1852 <i>current time-slice</i> that is considered for the drawings. If the checkbox
1853 <i>Update Drawings on Sliders Change</i> is not selected, the button
1854 <i>Apply</i> must be clicked in order to inform triva that the
1855 new time-slice must be considered. The bottom part of the window, in the space
1856 indicated by the square <i>Time Slice Animation</i> can be used to advance
1857 the time-frame automatically. The user configures the amount of time that the
1858 time-frame will forward and how frequent this update will happen. Once this is
1859 configured, the user clicks the <i>Play</i> button in order to see the dynamic
1860 changes on the drawings.
1863 <a href="triva-time_interval.png" border=0><img src="triva-time_interval.png" width="50%" border=0></a>
1866 <b>Remarks:</b> when the trace has too many hosts or links, the computation to
1867 take into account a new time-slice can be expensive. When this happens, the
1868 <i>Frequency</i> parameter, but also updates caused by change on configurations
1869 when the checkbox <i>Update Drawings on Sliders
1870 Change</i> is selected will not be followed.
1872 - <b>Understanding Triva - graph</b>: this part of the documention explains how
1873 to analyze the traces using the graph view of Triva, when the user executes
1874 the tool passing <em>--graph</em> as parameter. Triva opens three windows when
1875 this parameter is used: the <i>Time Interval</i> window (previously described),
1876 the <i>Graph Representation</i> window, and the <em>Graph Configuration</em>
1877 window. The Graph Representation is the window where drawings take place.
1878 Initially, it is completely white waiting for a proper graph configuration input
1879 by the user. We start the description of this type of analysis by describing the
1880 <i>Graph Configuration</i> window (depicted below). By using a particular
1881 configuration, triva
1882 can be used to customize the graph drawing according to
1883 the SimGrid trace that was created with user-specific categories. Before delving
1884 into the details of this customization, let us first explain the major parts of
1885 the graph configuration window. The buttons located in the top-right corner can
1886 be used to delete, copy and create a new configuration. The checkbox in the
1887 top-middle part of the window indicates if the configuration typed in the
1888 textfield is syntactically correct (we are using the non-XML
1889 <a href="http://en.wikipedia.org/wiki/Property_list">Property List Format</a> to
1890 describe the configuration). The pop-up button located on the top-left corner
1891 indicates the selected configuration (the user can have multiple graph
1892 configurations). The bottom-left text field contains the name of the current
1893 configuration (updates on this field must be followed by typing enter on the
1894 keyboard to take into account the name change). The bottom-right <em>Apply</em>
1895 button activates the current configuration, resulting on an update on the graph
1899 <a href="triva-graph_configuration.png" border=0><img src="triva-graph_configuration.png" width="50%" border=0></a>
1902 <b>Basic SimGrid Configuration</b>: The figure shows in the big textfield the
1903 basic configuration that should be used during the analysis of a SimGrid trace
1904 file. The basic logic of the configuration is as follows:
1910 The nodes of the graph will be created based on the <i>node</i> parameter, which
1911 in this case is the different <em>"HOST"</em>s of the platform
1912 used to simulate. The <i>edge</i> parameter indicates that the edges of the
1913 graph will be created based on the <em>"LINK"</em>s of the platform. After the
1914 definition of these two parameters, the configuration must detail how
1915 <em>HOST</em>s and <em>LINK</em>s should be drawn. For that, the configuration
1916 must have an entry for each of the types used. For <em>HOST</em>, as basic
1917 configuration, we have:
1924 The parameter <em>size</em> indicates which variable from the trace file will be
1925 used to define the size of the node HOST in the visualization. If the simulation
1926 was executed with availability traces, the size of the nodes will be changed
1927 according to these traces. The parameter <em>scale</em> indicates if the value
1928 of the variable is <em>global</em> or <em>local</em>. If it is global, the value
1929 will be relative to the power of all other hosts, if it is local, the value will
1930 be relative locally.
1931 For <em>LINK</em> we have:
1941 For the types specified in the <em>edge</em> parameter (such as <em>LINK</em>),
1942 the configuration must contain two additional parameters: <em>src</em> and
1943 <em>dst</em> that are used to properly identify which nodes this edge is
1944 connecting. The values <em>SrcHost</em> and <em>DstHost</em> are always present
1945 in the SimGrid trace file and should not be changed in the configuration. The
1946 parameter <em>size</em> for the LINK, in this case, is configured as the
1947 variable <em>bandwidth</em>, with a <em>global</em> scale. The scale meaning
1948 here is exactly the same used for nodes. The last parameter is the GraphViz
1949 algorithm used to calculate the position of the nodes in the graph
1952 graphviz-algorithm = neato;
1955 <b>Customizing the Graph Representation</b>: triva is capable to handle
1956 a customized graph representation based on the variables present in the trace
1957 file. In the case of SimGrid, every time a category is created for tasks, two
1958 variables in the trace file are defined: one to indicate node utilization (how
1959 much power was used by that task category), and another to indicate link
1960 utilization (how much bandwidth was used by that category). For instance, if the
1961 user declares a category named <i>request</i>, there will be variables named
1962 <b>p</b><i>request</i> and a <b>b</b><i>request</i> (<b>p</b> for power and
1963 <b>b</b> for bandwidth). It is important to notice that the variable
1964 <i>prequest</i> in this case is only available for HOST, and
1965 <i>brequest</i> is only available for LINK. <b>Example</b>: suppose there are
1966 two categories for tasks: request and compute. To create a customized graph
1967 representation with a proportional separation of host and link utilization, use
1968 as configuration for HOST and LINK this:
1977 values = (prequest, pcomputation);
1990 values = (brequest, bcomputation);
1994 Where <i>sep_host</i> contains a composition of type <i>separation</i> where
1995 its max size is the <i>power</i> of the host and the variables <i>prequest</i>
1996 and <i>pcomputation</i> are drawn proportionally to the size of the HOST. And
1997 <i>sep_link</i> is also a separation where max is defined as the
1998 <i>bandwidth</i> of the link, and the variables <i>brequest</i> and
1999 <i>bcomputation</i> are drawn proportionally within a LINK.
2000 <i>This configuration enables the analysis of resource utilization by MSG tasks,
2001 and the identification of load-balancing issues, network bottlenecks, for
2003 <b>Other compositions</b>: besides <i>separation</i>, it is possible to use
2004 other types of compositions, such as gradients, and colors, like this:
2009 values = (numberOfTasks);
2013 values = (is_server);
2016 Where <i>gra_host</i> creates a gradient within a node of the graph, using a
2017 global scale and using as value a variable called <i>numberOfTasks</i>, that
2018 could be declared by the user using the optional tracing functions of SimGrid.
2019 If scale is global, the max and min value for the gradient will be equal to the
2020 max and min numberOfTasks among all hosts, and if scale is local, the max and
2021 min value based on the value of numberOfTasks locally in each host.
2022 And <i>color_host</i> composition draws a square based on a positive value of
2023 the variable <i>is_server</i>, that could also be defined by the user using the
2024 SimGrid tracing functions. \n
2025 <b>The Graph Visualization</b>: The next figure shows a graph visualization of a
2026 given time-slice of the masterslave_forwarder example (present in the SimGrid
2027 sources). The red color indicates tasks from the <i>compute</i> category. This
2028 visualization was generated with the following configuration:
2041 values = (pcompute, pfinalize);
2053 values = (bcompute, bfinalize);
2056 graphviz-algorithm = neato;
2061 <a href="triva-graph_visualization.png" border=0><img src="triva-graph_visualization.png" width="50%" border=0></a>
2065 - <b>Understading Triva - colors</b>: An important issue when using Triva is how
2066 to define colors. To do that, we have to know which variables are defined in
2067 the trace file generated by the SimGrid library. The parameter <em>--list</em>
2068 lists the variables for a given trace file:
2070 $ Triva -l masterslave_forwarder.trace
2088 We can see that HOST has seven variables (from power to pfinalize) and LINK has
2089 four (from bandwidth to bfinalize). To define a red color for the
2090 <i>pcompute</i> and <i>bcompute</i> (which are defined based on user category
2091 <i>compute</i>), execute:
2093 $ defaults write Triva 'pcompute Color' '1 0 0'
2094 $ defaults write Triva 'bcompute Color' '1 0 0'
2096 Where the three numbers in each line are the RGB color with values from 0 to 1.
2098 \subsection faq_modelchecking Model-Checking
2099 \subsubsection faq_modelchecking_howto How to use it
2100 To enable the experimental SimGrid model-checking support the program should
2101 be executed with the command line argument
2105 Properties are expressed as assertions using the function
2107 void MC_assert(int prop);
2110 \subsection faq_binding_lua Lua Binding
2111 Most of Simgrid modules require a good level in C programming ,
2112 since simgrid is used to be as standard C library .
2113 Sometime ( for some reason or another ) developers prefer using some kind of « easy scripts »
2114 (something like … lua ? Ruby ? ...?) or a language easier to code with ( Java ? ) for their works ,
2115 which avoid dealing with C errors , and sometime an important gain of time (coding-time?) .
2116 Besides Java Binding , Lua and Ruby bindings are available now( since version 3.4 of Simgrid )
2117 for MSG Module , and we are currenlty working on bindings for other modules .
2120 \subsubsection faq_binding_lua_about What is lua ?
2121 Lua (Moon for portuguese !) is a lightweight, reflective, imperative and functional programming language,
2122 designed as a scripting language with extensible semantics as a primary goal.(see official web site <a href="http://www.lua.org">here</a>)
2123 \subsubsection faq_binding_lua_why Why lua ?
2124 Lua is a fast,portable and powerful script language , quite simple to use for developpers .
2125 it combines procedural features with powerful data description facilities,
2126 by using a simple, yet powerful, mechanism of tables.
2127 Lua has a relatively simple C API compared to other scripting languages,
2128 and accordingly it provides a robust, easy to use it.
2129 \subsubsection faq_binding_lua_simgrid How to use lua in Simgrid ?
2130 Actually , the use of lua in Simgrid is quite simple , you have just to follow the same steps as coding with C in Simgird ,
2131 but this time , code with Lua ;) :
2132 - Coding functions coresponding to each process
2133 - loading the platforme/deployment XML file that describe the environment of simulation
2134 - and … Running the Simulation !!!
2136 \subsubsection faq_binding_lua_example_master_slave Master/Slave Example
2139 function Master(...)
2143 slave_count = arg[4]
2144 -- Dispatch the tasks
2146 tk = simgrid.Task.new("Task "..i,comp_size,comm_size);
2147 alias = "slave "..(i%slave_count);
2148 simgrid.info("Master sending ’" .. simgrid.Task.name(tk) .."’ To ’" .. alias .."’");
2149 simgrid.Task.send(tk,alias);
2150 simgrid.info("Master done sending ’".. simgrid.Task.name(tk) .."’ To ’" .. alias .."’");
2152 -- Sending Finalize Message To Others
2153 for i=0,slave_count-1 do
2154 alias = "slave "..i;
2155 simgrid.info("Master: sending finalize to "..alias);
2156 finalize = simgrid.Task.new("finalize",comp_size,comm_size);
2157 simgrid.Task.send(finalize,alias)
2161 we mainly use simgrid.Task.new(task_name,computation_size,communication_size) to create our MSG Task ,
2162 then simgrid.Task.send(task,alias) to send it .
2163 we use also simgrid.Task.name(task), to get the task's name .
2168 local my_mailbox="slave "..arg[1]
2170 local tk = simgrid.Task.recv(my_mailbox);
2171 if (simgrid.Task.name(tk) == "finalize") then
2172 simgrid.info("Slave ’" ..my_mailbox.."’ got finalize msg");
2175 simgrid.Task.execute(tk)
2177 simgrid.info("Slave ’" ..my_mailbox.."’: I’m Done . See You !!");
2180 Here , we could see how we use simgrid.Task.recv(alias) to receive a task with a specific alias ,
2181 this function return directly the task recevied .
2183 \li Set Environmenet and run application
2186 simgrid.platform("my_platform.xml")
2187 simgrid.application("my_deployment.xml")
2189 simgrid.info("Simulation’s over.See you.")
2193 \subsubsection faq_binding_lua_example_data Exchanging Data
2194 You can also exchange data between Process using lua .for that , you have to deal with lua task as a table ,
2195 since lua is based itself on a mechanism of tables ,
2196 so you can exchange any kind of data ( tables, matrix , strings … ) between process via tasks.
2200 task = simgrid.Task.new("data_task",task_comp,task_comm);
2201 task['matrix'] = my_matrix;
2202 task['table'] = my_table;
2203 task['message'] = "Hello from (Lua || Simgrid ) !! "
2205 simgrid.Task.send(task,alias)
2207 After creating task , we associate to it various kind of data with a specific key , ( string in this case)
2208 to distinguish between data variables . Via this key the receiver could access easily to datas .
2211 \li Receiver processe
2213 task = simgrid.Task.recv(alias);
2214 sender_matrix = task['matrix'];
2215 sender_table = task['table'];
2216 sender_message = task['message']
2219 Note that in lua , both sender and receiver share the same lua task !
2220 So that the receiver could joint data directly on the received task without sending it back .
2221 You can find a complet example ( matrix multiplication case ) in the file example/lua/mult_matrix.lua
2224 \subsubsection faq_binding_lua_example_bypass Bypass XML
2225 maybe you wonder if there is a way to bypass the XML files ,
2226 and describe your platform directly from the code , with lua bindings it's Possible !! how ?
2227 We provide some additional (tricky?) functions in lua that allows you to set up your own platform without using the XML files
2228 ( this can be useful for large platforms , so a simple for loop will avoid you to deal with an annoying XML File ;) )
2233 simgrid.Host.new("Tremblay",98095000);
2234 simgrid.Host.new("Jupiter",76296000);
2235 simgrid.Host.new("Fafard",76296000);
2236 simgrid.Host.new("Ginette",48492000);
2237 simgrid.Host.new("Bourassa",48492000);
2239 we use simgrid.Host.new(host_id,power) to instanciate our hosts.
2244 simgrid.Link.new(i,252750+ i*768,0.000270544+i*0.087); -- some crazy values ;)
2247 we used simgrid.Link.new(link_id,bandwidth,latency) with a simple for loop to create all links we need ( much easier than XML hein ? )
2251 -- simgrid.Route.new(src_id,des_id,links_nb,links_list)
2252 simgrid.Route.new("Tremblay","Jupiter",1,{"1"});
2253 simgrid.Route.new("Tremblay","Fafard",6,{"0","1","2","3","4","8"});
2254 simgrid.Route.new("Tremblay","Ginette",3,{"3","4","5"});
2255 simgrid.Route.new("Tremblay","Bourassa",7,{"0","1","3","2","4","6","7"});
2257 simgrid.Route.new("Jupiter","Tremblay",1,{"1"});
2258 simgrid.Route.new("Jupiter","Fafard",7,{"0","1","2","3","4","8","9"});
2259 simgrid.Route.new("Jupiter","Ginette",4,{"3","4","5","9"});
2260 simgrid.Route.new("Jupiter","Bourassa",8,{"0","1","2","3","4","6","7","9"});
2263 for each host you have to specify which route to choose to access to the rest of hosts connected in the grid .
2267 simgrid.register_platform();
2269 Don't forget to register your platform , that SURF callbacks starts their work ;)
2273 simgrid.Host.setFunction("Tremblay","Master",4,{"20","550000000","1000000","4"});
2274 simgrid.Host.setFunction("Bourassa","Slave",1,{"0"});
2275 simgrid.Host.setFunction("Jupiter","Slave",1,{"1"});
2276 simgrid.Host.setFunction("Fafard","Slave",1,{"2"});
2277 simgrid.Host.setFunction("Ginette","Slave",1,{"3"});
2279 you don't need to use a deployment XML file , thanks to simgrid.Host.setFunction(host_id,function,args_number,args_list)
2280 you can associate functions for each host with arguments if needed .
2284 simgrid.register_application();
2286 Yes , Here too you have to resgiter your application before running the simulation .
2288 the full example is distributed in the file examples/lua/master_slave_bypass.lua
2290 \section faq_troubleshooting Troubleshooting
2292 \subsection faq_trouble_lib_compil SimGrid compilation and installation problems
2294 \subsubsection faq_trouble_lib_config ./configure fails!
2296 We know only one reason for the configure to fail:
2298 - <b>You are using a broken build environment</b>\n
2299 If symptom is that configure complains about gcc not being able to build
2300 executables, you are probably missing the libc6-dev package. Damn Ubuntu.
2302 If you experience other kind of issue, please get in touch with us. We are
2303 always interested in improving our portability to new systems.
2305 \subsubsection faq_trouble_distcheck Dude! "make check" fails on my machine!
2307 Don't assume we never run this target, because we do. Check
2308 http://bob.loria.fr:8010 if you don't believe us.
2310 There is several reasons which may cause the make check to fail on your
2313 - <b>You are using a broken libc (probably concerning the contextes)</b>.\n
2314 The symptom is that the "make check" fails within the examples/msg directory.\n
2315 By default, SimGrid uses something called ucontexts. This is part of the
2316 libc, but it's quite undertested. For example, some (old) versions of the
2317 glibc on alpha do not implement these functions, but provide the stubs
2318 (which return ENOSYS: not implemented). It may fool our detection mechanism
2319 and leads to segfaults. There is not much we can do to fix the bug.
2320 A workaround is to compile with --with-context=pthread to avoid
2321 ucontext completely. You'll be a bit more limited in the number
2322 of simulated processes you can start concurrently, but 5000
2323 processes is still enough for most purposes, isn't it?\n
2324 This limitation is the reason why we insist on using this piece of ...
2325 software even if it's so troublesome.\n
2326 <b>=> use --with-pthread on AMD64 architecture that do not have an
2327 ultra-recent libc.</b>
2329 - <b>There is a bug in SimGrid we aren't aware of</b>.\n
2330 If none of the above apply, please drop us a mail on the mailing list so
2331 that we can check it out. Make sure to read \ref faq_bugrepport
2334 \subsection faq_trouble_compil User code compilation problems
2336 \subsubsection faq_trouble_err_logcat "gcc: _simgrid_this_log_category_does_not_exist__??? undeclared (first use in this function)"
2338 This is because you are using the log mecanism, but you didn't created
2339 any default category in this file. You should refer to \ref XBT_log
2340 for all the details, but you simply forgot to call one of
2341 XBT_LOG_NEW_DEFAULT_CATEGORY() or XBT_LOG_NEW_DEFAULT_SUBCATEGORY().
2343 \subsubsection faq_trouble_pthreadstatic "gcc: undefined reference to pthread_key_create"
2345 This indicates that one of the library SimGrid depends on (libpthread
2346 here) was missing on the linking command line. Dependencies of
2347 libsimgrid are expressed directly in the dynamic library, so it's
2348 quite impossible that you see this message when doing dynamic linking.
2350 If you compile your code statically (and if you use a pthread version
2351 of SimGrid -- see \ref faq_more_processes), you must absolutely
2352 specify <tt>-lpthread</tt> on the linker command line. As usual, this should
2353 come after <tt>-lsimgrid</tt> on this command line.
2355 \subsection faq_trouble_errors Runtime error messages
2357 \subsubsection faq_flexml_limit "surf_parse_lex: Assertion `next limit' failed."
2359 This is because your platform file is too big for the parser.
2361 Actually, the message comes directly from FleXML, the technology on top of
2362 which the parser is built. FleXML has the bad idea of fetching the whole
2363 document in memory before parsing it. And moreover, the memory buffer size
2364 must be determined at compilation time.
2366 We use a value which seems big enough for our need without bloating the
2367 simulators footprints. But of course your mileage may vary. In this case,
2368 just edit src/surf/surfxml.l modify the definition of
2369 FLEXML_BUFFERSTACKSIZE. E.g.
2372 #define FLEXML_BUFFERSTACKSIZE 1000000000
2375 Then recompile and everything should be fine, provided that your version of
2376 Flex is recent enough (>= 2.5.31). If not the compilation process should
2379 A while ago, we worked on FleXML to reduce a bit its memory consumption, but
2380 these issues remain. There is two things we should do:
2382 - use a dynamic buffer instead of a static one so that the only limit
2383 becomes your memory, not a stupid constant fixed at compilation time
2384 (maybe not so difficult).
2385 - change the parser so that it does not need to get the whole file in
2386 memory before parsing
2387 (seems quite difficult, but I'm a complete newbe wrt flex stuff).
2389 These are changes to FleXML itself, not SimGrid. But since we kinda hijacked
2390 the development of FleXML, I can grant you that any patches would be really
2391 welcome and quickly integrated.
2393 <b>Update:</b> A new version of FleXML (1.7) was released. Most of the work
2394 was done by William Dowling, who use it in his own work. The good point is
2395 that it now use a dynamic buffer, and that the memory usage was greatly
2396 improved. The downside is that William also changed some things internally,
2397 and it breaks the hack we devised to bypass the parser, as explained in
2398 \ref faq_flexml_bypassing. Indeed, this is not a classical usage of the
2399 parser, and Will didn't imagine that we may have used (and even documented)
2400 such a crude usage of FleXML. So, we now have to repair the bypassing
2401 functionality to use the lastest FleXML version and fix the memory usage in
2404 \subsubsection faq_trouble_gras_transport GRAS spits networking error messages
2406 Gras, on real platforms, naturally use regular sockets to communicate. They
2407 are deeply hidden in the gras abstraction, but when things go wrong, you may
2408 get some weird error messages. Here are some example, with the probable
2411 - <b>Transport endpoint is not connected</b>: several processes try to open
2412 a server socket on the same port number of the same machine. This is
2413 naturally bad and each process should pick its own port number for this.\n
2414 Maybe, you just have some processes remaining from a previous experiment
2416 Killing them may help, but again if you kill -KILL them, you'll have to
2417 wait for a while: they didn't close there sockets properly and the system
2418 needs a while to notice that this port is free again.
2420 - <b>Socket closed by remote side</b>: if the remote process is not
2421 supposed to close the socket at this point, it may be dead.
2423 - <b>Connection reset by peer</b>: I found this on Internet about this
2424 error. I think it's what's happening here, too:\n
2425 <i>This basically means that a network error occurred while the client was
2426 receiving data from the server. But what is really happening is that the
2427 server actually accepts the connection, processes the request, and sends
2428 a reply to the client. However, when the server closes the socket, the
2429 client believes that the connection has been terminated abnormally
2430 because the socket implementation sends a TCP reset segment telling the
2431 client to throw away the data and report an error.\n
2432 Sometimes, this problem is caused by not properly closing the
2433 input/output streams and the socket connection. Make sure you close the
2434 input/output streams and socket connection properly. If everything is
2435 closed properly, however, and the problem persists, you can work around
2436 it by adding a one-second sleep before closing the streams and the
2437 socket. This technique, however, is not reliable and may not work on all
2439 Since GRAS sockets are closed properly (repeat after me: there is no bug
2440 in GRAS), it is either that you are closing your sockets on server side
2441 before the client get a chance to read them (use gras_os_sleep() to delay
2442 the server), or the server died awfully before the client got the data.
2444 \subsubsection faq_trouble_errors_big_fat_warning I'm told that my XML files are too old.
2446 The format of the XML platform description files is sometimes
2447 improved. For example, we decided to change the units used in SimGrid
2448 from MBytes, MFlops and seconds to Bytes, Flops and seconds to ease
2449 people exchanging small messages. We also reworked the route
2450 descriptions to allow more compact descriptions.
2452 That is why the XML files are versionned using the 'version' attribute
2453 of the root tag. Currently, it should read:
2455 <platform version="2">
2458 If your files are too old, you can use the simgrid_update_xml.pl
2459 script which can be found in the tools directory of the archive.
2461 \subsection faq_trouble_valgrind Valgrind-related and other debugger issues
2463 If you don't, you really should use valgrind to debug your code, it's
2466 \subsubsection faq_trouble_vg_longjmp longjmp madness in valgrind
2468 This is when valgrind starts complaining about longjmp things, just like:
2470 \verbatim ==21434== Conditional jump or move depends on uninitialised value(s)
2471 ==21434== at 0x420DBE5: longjmp (longjmp.c:33)
2473 ==21434== Use of uninitialised value of size 4
2474 ==21434== at 0x420DC3A: __longjmp (__longjmp.S:48)
2477 This is the sign that you didn't used the exception mecanism well. Most
2478 probably, you have a <tt>return;</tt> somewhere within a <tt>TRY{}</tt>
2479 block. This is <b>evil</b>, and you must not do this. Did you read the section
2482 \subsubsection faq_trouble_vg_libc Valgrind spits tons of errors about backtraces!
2484 It may happen that valgrind, the memory debugger beloved by any decent C
2485 programmer, spits tons of warnings like the following :
2486 \verbatim ==8414== Conditional jump or move depends on uninitialised value(s)
2487 ==8414== at 0x400882D: (within /lib/ld-2.3.6.so)
2488 ==8414== by 0x414EDE9: (within /lib/tls/i686/cmov/libc-2.3.6.so)
2489 ==8414== by 0x400B105: (within /lib/ld-2.3.6.so)
2490 ==8414== by 0x414F937: _dl_open (in /lib/tls/i686/cmov/libc-2.3.6.so)
2491 ==8414== by 0x4150F4C: (within /lib/tls/i686/cmov/libc-2.3.6.so)
2492 ==8414== by 0x400B105: (within /lib/ld-2.3.6.so)
2493 ==8414== by 0x415102D: __libc_dlopen_mode (in /lib/tls/i686/cmov/libc-2.3.6.so)
2494 ==8414== by 0x412D6B9: backtrace (in /lib/tls/i686/cmov/libc-2.3.6.so)
2495 ==8414== by 0x8076446: xbt_dictelm_get_ext (dict_elm.c:714)
2496 ==8414== by 0x80764C1: xbt_dictelm_get (dict_elm.c:732)
2497 ==8414== by 0x8079010: xbt_cfg_register (config.c:208)
2498 ==8414== by 0x806821B: MSG_config (msg_config.c:42)
2501 This problem is somewhere in the libc when using the backtraces and there is
2502 very few things we can do ourselves to fix it. Instead, here is how to tell
2503 valgrind to ignore the error. Add the following to your ~/.valgrind.supp (or
2504 create this file on need). Make sure to change the obj line according to
2505 your personnal mileage (change 2.3.6 to the actual version you are using,
2506 which you can retrieve with a simple "ls /lib/ld*.so").
2509 name: Backtrace madness
2511 obj:/lib/ld-2.3.6.so
2516 fun:__libc_dlopen_mode
2519 Then, you have to specify valgrind to use this suppression file by passing
2520 the <tt>--suppressions=$HOME/.valgrind.supp</tt> option on the command line.
2521 You can also add the following to your ~/.bashrc so that it gets passed
2522 automatically. Actually, it passes a bit more options to valgrind, and this
2523 happen to be my personnal settings. Check the valgrind documentation for
2526 \verbatim export VALGRIND_OPTS="--leak-check=yes --leak-resolution=high --num-callers=40 --tool=memcheck --suppressions=$HOME/.valgrind.supp" \endverbatim
2528 \subsubsection faq_trouble_backtraces Truncated backtraces
2530 When debugging SimGrid, it's easier to pass the
2531 --disable-compiler-optimization flag to the configure if valgrind or
2532 gdb get fooled by the optimization done by the compiler. But you
2533 should remove these flag when everything works before going in
2534 production (before launching your 1252135 experiments), or everything
2535 will run only one half of the true SimGrid potential.
2537 \subsection faq_deadlock There is a deadlock in my code!!!
2539 Unfortunately, we cannot debug every code written in SimGrid. We
2540 furthermore believe that the framework provides ways enough
2541 information to debug such informations yourself. If the textual output
2542 is not enough, Make sure to check the \ref faq_visualization FAQ entry to see
2543 how to get a graphical one.
2545 Now, if you come up with a really simple example that deadlocks and
2546 you're absolutely convinced that it should not, you can ask on the
2547 list. Just be aware that you'll be severely punished if the mistake is
2548 on your side... We have plenty of FAQ entries to redact and new
2549 features to implement for the impenitents! ;)
2551 \subsection faq_surf_network_latency I get weird timings when I play with the latencies.
2553 OK, first of all, remember that units should be Bytes, Flops and
2554 Seconds. If you don't use such units, some SimGrid constants (e.g. the
2555 SG_TCP_CTE_GAMMA constant used in most network models) won't have the
2556 right unit and you'll end up with weird results.
2558 Here is what happens with a single transfer of size L on a link
2559 (bw,lat) when nothing else happens.
2562 0-----lat--------------------------------------------------t
2563 |-----|**** real_bw =min(bw,SG_TCP_CTE_GAMMA/(2*lat)) *****|
2566 In more complex situations, this min is the solution of a complex
2567 max-min linear system. Have a look
2568 <a href="http://lists.gforge.inria.fr/pipermail/simgrid-devel/2006-April/thread.html">here</a>
2569 and read the two threads "Bug in SURF?" and "Surf bug not
2570 fixed?". You'll have a few other examples of such computations. You
2571 can also read "A Network Model for Simulation of Grid Application" by
2572 Henri Casanova and Loris Marchal to have all the details. The fact
2573 that the real_bw is smaller than bw is easy to understand. The fact
2574 that real_bw is smaller than SG_TCP_CTE_GAMMA/(2*lat) is due to the
2575 window-based congestion mechanism of TCP. With TCP, you can't exploit
2576 your huge network capacity if you don't have a good round-trip-time
2577 because of the acks...
2579 Anyway, what you get is t=lat + L/min(bw,SG_TCP_CTE_GAMMA/(2*lat)).
2581 * if I you set (bw,lat)=(100 000 000, 0.00001), you get t = 1.00001 (you fully
2583 * if I you set (bw,lat)=(100 000 000, 0.0001), you get t = 1.0001 (you're on the
2585 * if I you set (bw,lat)=(100 000 000, 0.001), you get t = 10.001 (ouch!)
2587 This bound on the effective bandwidth of a flow is not the only thing
2588 that may make your result be unexpected. For example, two flows
2589 competing on a saturated link receive an amount of bandwidth inversely
2590 proportional to their round trip time.
2592 \subsection faq_bugrepport So I've found a bug in SimGrid. How to report it?
2594 We do our best to make sure to hammer away any bugs of SimGrid, but this is
2595 still an academic project so please be patient if/when you find bugs in it.
2596 If you do, the best solution is to drop an email either on the simgrid-user
2597 or the simgrid-devel mailing list and explain us about the issue. You can
2598 also decide to open a formal bug report using the
2599 <a href="https://gforge.inria.fr/tracker/?atid=165&group_id=12&func=browse">relevant
2600 interface</a>. You need to login on the server to get the ability to submit
2603 We will do our best to solve any problem repported, but you need to help us
2604 finding the issue. Just telling "it segfault" isn't enough. Telling "It
2605 segfaults when running the attached simulator" doesn't really help either.
2606 You may find the following article interesting to see how to repport
2607 informative bug repports:
2608 http://www.chiark.greenend.org.uk/~sgtatham/bugs.html (it is not SimGrid
2609 specific at all, but it's full of good advices).
2611 \author Arnaud Legrand (arnaud.legrand::imag.fr)
2612 \author Martin Quinson (martin.quinson::loria.fr)
2617 ******************************************************************
2618 * OLD CRUFT NOT USED ANYMORE *
2619 ******************************************************************
2622 \subsection faq_crosscompile Cross-compiling a Windows DLL of SimGrid from linux
2624 At the moment, we do not distribute Windows pre-compiled version of SimGrid
2625 because the support for this platform is still experimental. We know that
2626 some parts of the GRAS environment do not work, and we think that the others
2627 environments (MSG and SD) have good chances to work, but we didn't test
2628 ourselves. This section explains how we generate the SimGrid DLL so that you
2629 can build it for yourself. First of all, you need to have a version more
2630 recent than 3.1 (ie, a SVN version as time of writting).
2632 In order to cross-compile the package to windows from linux, you need to
2633 install mingw32 (minimalist gnu win32). On Debian, you can do so by
2634 installing the packages mingw32 (compiler), mingw32-binutils (linker and
2635 so), mingw32-runtime.
2637 You can use the VPATH support of configure to compile at the same time for
2638 linux and windows without dupplicating the source nor cleaning the tree
2639 between each. Just run bootstrap (if you use the SVN) to run the autotools.
2640 Then, create a linux and a win directories. Then, type:
2641 \verbatim cd linux; ../configure --srcdir=.. <usual configure flags>; make; cd ..
2642 cd win; ../configure --srcdir=.. --host=i586-mingw32msvc <flags>; make; cd ..
2644 The trick to VPATH builds is to call configure from another directory,
2645 passing it an extra --srcdir argument to tell it where all the sources are.
2646 It will understand you want to use VPATH. Then, the trick to cross-compile
2647 is simply to add a --host argument specifying the target you want to build
2648 for. The i586-mingw32msvc string is what you have to pass to use the mingw32
2649 environment as distributed in Debian.
2651 After that, you can run all make targets from both directories, and test
2652 easily that what you change for one arch does not break the other one.
2654 It is possible that this VPATH build thing breaks from time to time in the
2655 SVN since it's quite fragile, but it's granted to work in any released
2656 version. If you experience problems, drop us a mail.
2658 Another possible source of issue is that at the moment, building the
2659 examples request to use the gras_stub_generator tool, which is a compiled
2660 program, not a script. In cross-compilation, you need to cross-execute with
2661 wine for example, which is not really pleasant. We are working on this, but
2662 in the meanwhile, simply don't build the examples in cross-compilation
2663 (<tt>cd src</tt> before running make).
2665 Program (cross-)compiled with mingw32 do request an extra DLL at run-time to be
2666 usable. For example, if you want to test your build with wine, you should do
2667 the following to put this library where wine looks for DLLs.
2669 cp /usr/share/doc/mingw32-runtime/mingwm10.dll.gz ~/.wine/c/windows/system/
2670 gunzip ~/.wine/c/windows/system/mingwm10.dll.gz
2673 The DLL is built in src/.libs, and installed in the <i>prefix</i>/bin directory
2674 when you run make install.
2676 If you want to use it in a native project on windows, you need to use
2677 simgrid.dll and mingwm10.dll. For each DLL, you need to build .def file
2678 under linux (listing the defined symbols), and convert it into a .lib file
2679 under windows (specifying this in a way that windows compilers like). To
2680 generate the def files, run (under linux):
2681 \verbatim echo "LIBRARY libsimgrid-0.dll" > simgrid.def
2682 echo EXPORTS >> simgrid.def
2683 nm libsimgrid-0.dll | grep ' T _' | sed 's/.* T _//' >> simgrid.def
2684 nm libsimgrid-0.dll | grep ' D _' | sed 's/.* D _//' | sed 's/$/ DATA/' >> simgrid.def
2686 echo "LIBRARY mingwm10.dll" > mingwm10.def
2687 echo EXPORTS >> mingwm10.def
2688 nm mingwm10.dll | grep ' T _' | sed 's/.* T _//' >> mingwm10.def
2689 nm mingwm10.dll | grep ' D _' | sed 's/.* D _//' | sed 's/$/ DATA/' >> mingwm10.def
2692 To create the import .lib files, use the <tt>lib</tt> windows tool (from
2693 MSVC) the following way to produce simgrid.lib and mingwm10.lib
2694 \verbatim lib /def:simgrid.def
2695 lib /def:mingwm10.def
2698 If you happen to use Borland C Builder, the right command line is the
2699 following (note that you don't need any file.def to get this working).
2700 \verbatim implib simgrid.lib libsimgrid-0.dll
2701 implib mingwm10.lib mingwm10.dll
2704 Then, set the following parameters in Visual C++ 2005:
2705 Linker -> Input -> Additional dependencies = simgrid.lib mingwm10.lib
2707 Just in case you wonder how to generate a DLL from libtool in another
2708 project, we added -no-undefined to any lib*_la_LDFLAGS variables so that
2709 libtool accepts to generate a dynamic library under windows. Then, to make
2710 it true, we pass any dependencies (such as -lws2 under windows or -lpthread
2711 on need) on the linking line. Passing such deps is a good idea anyway so
2712 that they get noted in the library itself, avoiding the users to know about
2713 our dependencies and put them manually on their compilation line. Then we
2714 added the AC_LIBTOOL_WIN32_DLL macro just before AC_PROG_LIBTOOL in the
2715 configure.ac. It means that we exported any symbols which need to be.
2716 Nowadays, functions get automatically exported, so we don't need to load our
2717 header files with tons of __declspec(dllexport) cruft. We only need to do so
2718 for data, but there is no public data in SimGrid so we are good.
