-/*! \page faq Frequently Asked Questions
+/*! \page FAQ Frequently Asked Questions
\htmlinclude .FAQ.doc.toc
\section faq_simgrid I'm new to SimGrid. I have some questions. Where should I start?
-You are at the right place... Having a look to these
-<a href="http://graal.ens-lyon.fr/~alegrand/articles/slides_g5k_simul.pdf">slides</a>
-(or to these
+You are at the right place... Having a look to these
+<a href="http://www.loria.fr/~quinson/blog/2010/06/28/Tutorial_at_HPCS/">the slides of the HPCS'10 tutorial</a>
+(or to these <a href="http://graal.ens-lyon.fr/~alegrand/articles/slides_g5k_simul.pdf">ancient
+slides</a>, or to these
<a href="http://graal.ens-lyon.fr/~alegrand/articles/Simgrid-Introduction.pdf">"obsolete" slides</a>)
may give you some insights on what SimGrid can help you to do and what
are its limitations. Then you definitely should read the \ref
-MSG_examples. There is also a mailing list: <simgrid-user@lists.gforge.inria.fr>.
+MSG_examples. The \ref GRAS_tut can also help you.
+
+If you are stuck at any point and if this FAQ cannot help you, please drop us a
+mail to the user mailing list: <simgrid-user@lists.gforge.inria.fr>.
\subsection faq_interfaces What is the difference between MSG, SimDag, and GRAS? Do they serve the same purpose?
With SimDag, you express your code as a collection of interdependent
parallel tasks. So, in this model, applications can be seen as a DAG of
-tasks.
+tasks. This is the interface of choice for people wanting to port old
+code designed for SimGrid v1 or v2 to the framework current version.
With both GRAS and MSG, your application is seen as a set of communicating
processes, exchanging data by the way of messages and performing computation
on their own.
The difference between both is that MSG is somehow easier to use, but GRAS
-is not limitated to the simulator. Once you're done writing your GRAS code,
-you can run your code both in the simulator or on a real platform. For this,
-there is two implementations of the GRAS interface, one for simulation, one
-for real execution. So, you just have to relink your code to chose one of
-both world.
-
-\subsection faq_generic First steps with SimGrid
-
-If you decide to go for the MSG interface, please read carefully the
-\ref MSG_examples. You'll find in \ref MSG_ex_master_slave a very
-simple consisting of a master (that owns a bunch of tasks and
-distributes them) , some slaves (that process tasks whenever they
-receive one) and some forwarder agents (that simply pass the tasks
-they receive to some slaves).
-
-If you decide to go for the GRAS interface, you should definitively
-read the \ref GRAS_tut. The first section constitutes an introduction
-to the tool and presents the model we use. The second section
-constitutes a complete step-by-step tutorial building a distributed
-application from the begining and exemplifying most of the GRAS
-features in the process. The last section groups some HOWTOS
-highlighting a given feature of the framework in a more concise way.
-
-If you decide to go for another interface, I'm afraid your only sources
-of information will be the source code and the mailing lists...
+is not limited to the simulator. Once you're done writing your GRAS code,
+you can run your code both in the simulator and on a real platform. For this,
+there are two implementations of the GRAS interface, one for simulation, and one
+for real execution. So, you just have to relink your code to choose one of
+both worlds.
\subsection faq_visualization Visualizing and analyzing the results
./msg_test small_platform.xml small_deployment.xml 2>&1 | ../../tools/MSG_visualization/colorize.pl
\endverbatim
-We also have a more graphical output. Have a look at MSG_paje_output(). It
-generates an input to <a href="http://www-id.imag.fr/Logiciels/paje/">Paje</a>.
-<center>
-\htmlonly
- <a href="Paje_MSG_screenshot.jpg"><img src="Paje_MSG_screenshot_thn.jpg"></a>
-\endhtmlonly
-</center>
-
-Vizualization with Paje can be seen as a kind of postmortem
-analysis. However, as soon as you start playing with big simulations,
-you'll realize that processing such output is kind of tricky. There is
-so much generic informations that it is hard to find the information
-you are looking for.
-
-As a matter of fact, loging really depends on simulations (e.g. what
-kind of events is important...). That is why we do not propose a big
-dump of your whole simulation (it would slow everything down) but give
-you neat tools to structure you logs. Have a look at \ref XBT_log. In
-fact, rather than a post-mortem analysis, you may want to do it on the
-fly. The process you are running can do whatever you want. Have you
-thought about adding a global structure where you directly compute the
-informations that are really important rather than writing everything
-down and then processing huge files?
+We also have a more graphical output. Have a look at section \ref options_tracing.
\subsection faq_C Argh! Do I really have to code in C?
-Up until now, there is no binding for other languages. If you use C++,
+Currently bindings on top of MSG are supported for Java, Ruby and Lua. You can find a few
+documentation about them on the doc page. Note that bindings are released separately from the main dist
+and so have their own version numbers.
+
+Moreover If you use C++,
you should be able to use the SimGrid library as a standard C library
and everything should work fine (simply <i>link</i> against this
library; recompiling SimGrid with a C++ compiler won't work and it
wouldn't help if you could).
-In fact, we are currently working on Java bindings of MSG to allow
-all the undergrad students of the world to use this tool. This is a
-little more tricky than I would have expected, but the work is moving
-fast forward [2006/05/13]. More languages are evaluated, but for now,
-we do not feel a real demand for any other language. Please speak up!
-
-\section faq_installation Installing the SimGrid library
-
-Many people have been asking me questions on how to use SimGrid. Quite
-often, the questions were not really about SimGrid but on the
-installation process. This section is intended to help people that are
-not familiar with compiling C files under UNIX. If you follow these
-instructions and still have some troubles, drop an e-mail to
-<simgrid-user@lists.gforge.inria.fr>.
-
-\subsection faq_compiling Compiling SimGrid from an archive
-
-First of all, you need to download the latest version of SimGrid from
-<a href="http://gforge.inria.fr/frs/?group_id=12">here</a>.
-Suppose you have uncompressed SimGrid in some temporary location of
-your home directory (say <tt>/home/joe/tmp/simgrid-3.0.1 </tt>). The
-simplest way to use SimGrid is to install it in your home
-directory. Change your directory to
-<tt>/home/joe/tmp/simgrid-3.0.1</tt> and type
-
-\verbatim./configure --prefix=$HOME
-make
-make install
-\endverbatim
-
-If at some point, something fails, check the section "\ref
-faq_trouble_compil". If it does not help, you can report this problem to the
-list but, please, avoid sending a laconic mail like "There is a problem. Is it
-okay?". Send the config.log file which is automatically generated by
-configure. Try to capture both the standard output and the error output of the
-<tt>make</tt> command with <tt>script</tt>. There is no way for us to help you
-without the relevant bits of information.
-
-Now, the following directory should have been created :
-
- \li <tt>/home/joe/doc/simgrid/html/</tt>
- \li <tt>/home/joe/lib/</tt>
- \li <tt>/home/joe/include/</tt>
-
-SimGrid is not a binary, it is a library. Both a static and a dynamic
-version are available. Here is what you can find if you try a <tt>ls
-/home/joe/lib</tt>:
-
-\verbatim libsimgrid.a libsimgrid.la libsimgrid.so libsimgrid.so.0 libsimgrid.so.0.0.1
-\endverbatim
-
-Thus, there is two ways to link your program with SimGrid:
- \li Either you use the static version, e.g
-\verbatim gcc libsimgrid.a -o MainProgram MainProgram.c
-\endverbatim
- In this case, all the SimGrid functions are directly
- included in <tt>MainProgram</tt> (hence a bigger binary).
- \li Either you use the dynamic version (the preferred method)
-\verbatim gcc -lsimgrid -o MainProgram MainProgram.c
-\endverbatim
- In this case, the SimGrid functions are not included in
- <tt>MainProgram</tt> and you need to set your environment
- variable in such a way that <tt>libsimgrid.so</tt> will be
- found at runtime. This can be done by adding the following
- line in your .bashrc (if you use bash and if you have
- installed the SimGrid libraries in your home directory):
-\verbatim export LD_LIBRARY_PATH=$HOME/lib/:$LD_LIBRARY_PATH
-\endverbatim
-
-
-\subsection faq_compiling_svn Compiling SimGrid from the SVN
-
-The project development takes place in the svn, where all changes are
-commited when they happen. Then every once in a while, we make sure that the
-code quality meets our standard and release an archive from the code in the
-SVN. We afterward go back to the development in the SVN. So, if you need a
-recently added feature and can afford some little problem with the stability
-of the lastest features, you may want to use the SVN version instead of a
-released one.
-
-For that, you first need to get the "simgrid" module from
-<a href="http://gforge.inria.fr/scm/?group_id=12">here</a>.
-
-You won't find any <tt>configure</tt> and a few other things
-(<tt>Makefile.in</tt>'s, documentation, ...) will be missing as well. The
-reason for that is that all these files have to be regenerated using the
-latest versions of <tt>autoconf</tt>, <tt>libtool</tt>, <tt>automake</tt>
-(>1.9) and <tt>doxygen</tt> (>1.4). To generate the <tt>configure</tt> and
-the <tt>Makefile.in</tt>'s, you just have to launch the <tt>bootstrap</tt>
-command that resides in the top of the source tree. Then just follow the
-instructions of Section \ref faq_compiling.
-
-We insist on the fact that you really need the latest versions of
-autoconf, automake and libtool. Doing this step on exotic architectures/systems
-(i.e. anything different from a recent linux distribution) may be
-... uncertain. If you need to compile the SVN version on a machine where all these
-dependencies are not met, the easiest is to do <tt>make dist</tt> in the SVN
-dir of another machine where all dependencies are met. It will create an
-archive you may deploy on other sites just as a regular stable release.
-
-In summary, the following commands will checkout the SVN, regenerate the
-configure script and friends, configure SimGrid and build it.
-
-\verbatim svn checkout svn://scm.gforge.inria.fr/svn/simgrid/simgrid/trunk simgrid
-cd simgrid
-./bootstrap
-./configure --enable-maintainer-mode --prefix=<where to install SimGrid>
-make \endverbatim
-
-Then, if you want to install SimGrid on the current box, just do:
-\verbatim make install \endverbatim
-
-If you want to build an snapshot of the SVN to deploy it on another box (for
-example because the other machine don't have the autotools), do:
-\verbatim make dist \endverbatim
-
-Moreover, you should never call the autotools manually since you must run
-them in a specific order with specific arguments. Most of the times, the
-makefiles will automatically call the tools for you. When it's not possible
-(such as the first time you checkout the SVN), use the ./bootstrap command
-to call them explicitely.
-
-
-\subsection faq_setting_MSG Setting up your own MSG code
-
-Do not build your simulator by modifying the SimGrid examples. Go
-outside the SimGrid source tree and create your own working directory
-(say <tt>/home/joe/SimGrid/MyFirstScheduler/</tt>).
-
-Suppose your simulation has the following structure (remember it is
-just an example to illustrate a possible way to compile everything;
-feel free to organize it as you want).
-
- \li <tt>sched.h</tt>: a description of the core of the
- scheduler (i.e. which functions are can be used by the
- agents). For example we could find the following functions
- (master, forwarder, slave).
-
- \li <tt>sched.c</tt>: a C file including <tt>sched.h</tt> and
- implementing the core of the scheduler. Most of these
- functions use the MSG functions defined in section \ref
- msg_gos_functions.
-
- \li <tt>masterslave.c</tt>: a C file with the main function, i.e.
- the MSG initialization (MSG_global_init()), the platform
- creation (e.g. with MSG_create_environment()), the
- deployment phase (e.g. with MSG_function_register() and
- MSG_launch_application()) and the call to
- MSG_main()).
-
-To compile such a program, we suggest to use the following
-Makefile. It is a generic Makefile that we have used many times with
-our students when we teach the C language.
-
-\verbatim
-all: masterslave
-masterslave: masterslave.o sched.o
-
-INSTALL_PATH = $$HOME
-CC = gcc
-PEDANTIC_PARANOID_FREAK = -O0 -Wshadow -Wcast-align \
- -Waggregate-return -Wmissing-prototypes -Wmissing-declarations \
- -Wstrict-prototypes -Wmissing-prototypes -Wmissing-declarations \
- -Wmissing-noreturn -Wredundant-decls -Wnested-externs \
- -Wpointer-arith -Wwrite-strings -finline-functions
-REASONABLY_CAREFUL_DUDE = -Wall
-NO_PRAYER_FOR_THE_WICKED = -w -O2
-WARNINGS = $(REASONABLY_CAREFUL_DUDE)
-CFLAGS = -g $(WARNINGS)
-
-INCLUDES = -I$(INSTALL_PATH)/include
-DEFS = -L$(INSTALL_PATH)/lib/
-LDADD = -lm -lsimgrid
-LIBS =
-
-%: %.o
- $(CC) $(INCLUDES) $(DEFS) $(CFLAGS) $^ $(LIBS) $(LDADD) -o $@
-
-%.o: %.c
- $(CC) $(INCLUDES) $(DEFS) $(CFLAGS) -c -o $@ $<
-
-clean:
- rm -f $(BIN_FILES) *.o *~
-.SUFFIXES:
-.PHONY : clean
-
-\endverbatim
-
-The first two lines indicates what should be build when typing make
-(<tt>masterslave</tt>) and of which files it is to be made of
-(<tt>masterslave.o</tt> and <tt>sched.o</tt>). This makefile assumes
-that you have set up correctly your <tt>LD_LIBRARY_PATH</tt> variable
-(look, there is a <tt>LDADD = -lm -lsimgrid</tt>). If you prefer using
-the static version, remove the <tt>-lsimgrid</tt> and add a
-<tt>$(INSTALL_PATH)/lib/libsimgrid.a</tt> on the next line, right
-after the <tt>LIBS = </tt>.
-
-More generally, if you have never written a Makefile by yourself, type
-in a terminal : <tt>info make</tt> and read the introduction. The
-previous example should be enough for a first try but you may want to
-perform some more complex compilations...
-
-\subsection faq_setting_GRAS Setting up your own GRAS code
-
-If you use the GRAS interface instead of the MSG one, then previous section
-is not the better source of information. Instead, you should check the GRAS
-tutorial in general, and the \ref GRAS_tut_tour_setup in particular.
-
-\subsection faq_crosscompile Cross-compiling a Windows DLL of SimGrid from linux
-
-At the moment, we do not distribute Windows pre-compiled version of SimGrid
-because the support for this platform is still experimental. We know that
-some parts of the GRAS environment do not work, and we think that the others
-environments (MSG and SD) have good chances to work, but we didn't test
-ourselves. This section explains how we generate the SimGrid DLL so that you
-can build it for yourself. First of all, you need to have a version more
-recent than 3.1 (ie, a SVN version as time of writting).
-
-In order to cross-compile the package to windows from linux, you need to
-install mingw32 (minimalist gnu win32). On Debian, you can do so by
-installing the packages mingw32 (compiler), mingw32-binutils (linker and
-so), mingw32-runtime.
-
-You can use the VPATH support of configure to compile at the same time for
-linux and windows without dupplicating the source nor cleaning the tree
-between each. Just run bootstrap (if you use the SVN) to run the autotools.
-Then, create a linux and a win directories. Then, type:
-\verbatim cd linux; ../configure --srcdir=.. <usual configure flags>; make; cd ..
-cd win; ../configure --srcdir=.. --host=i586-mingw32msvc <flags>; make; cd ..
-\endverbatim
-The trick to VPATH builds is to call configure from another directory,
-passing it an extra --srcdir argument to tell it where all the sources are.
-It will understand you want to use VPATH. Then, the trick to cross-compile
-is simply to add a --host argument specifying the target you want to build
-for. The i586-mingw32msvc string is what you have to pass to use the mingw32
-environment as distributed in Debian.
-
-After that, you can run all make targets from both directories, and test
-easily that what you change for one arch does not break the other one.
-
-It is possible that this VPATH build thing breaks from time to time in the
-SVN since it's quite fragile, but it's granted to work in any released
-version. If you experience problems, drop us a mail.
-
-Another possible source of issue is that at the moment, building the
-examples request to use the gras_stub_generator tool, which is a compiled
-program, not a script. In cross-compilation, you need to cross-execute with
-wine for example, which is not really pleasant. We are working on this, but
-in the meanwhile, simply don't build the examples in cross-compilation
-(<tt>cd src</tt> before running make).
-
-Program (cross-)compiled with mingw32 do request an extra DLL at run-time to be
-usable. For example, if you want to test your build with wine, you should do
-the following to put this library where wine looks for DLLs.
-\verbatim
-cp /usr/share/doc/mingw32-runtime/mingwm10.dll.gz ~/.wine/c/windows/system/
-gunzip ~/.wine/c/windows/system/mingwm10.dll.gz
-\endverbatim
-
-The DLL is builded in src/.libs, and installed in the <i>prefix</i>/bin directory
-when you run make install.
-
-If you want to use it in a native project on windows, you need to use
-simgrid.dll and mingwm10.dll. For each DLL, you need to build .def file
-under linux (listing the defined symbols), and convert it into a .lib file
-under windows (specifying this in a way that windows compilers like). To
-generate the def files, run (under linux):
-\verbatim echo "LIBRARY libsimgrid-0.dll" > simgrid.def
-echo EXPORTS >> simgrid.def
-nm libsimgrid-0.dll | grep ' T _' | sed 's/.* T _//' >> simgrid.def
-nm libsimgrid-0.dll | grep ' D _' | sed 's/.* D _//' | sed 's/$/ DATA/' >> simgrid.def
-
-echo "LIBRARY mingwm10.dll" > mingwm10.def
-echo EXPORTS >> mingwm10.def
-nm mingwm10.dll | grep ' T _' | sed 's/.* T _//' >> mingwm10.def
-nm mingwm10.dll | grep ' D _' | sed 's/.* D _//' | sed 's/$/ DATA/' >> mingwm10.def
-\endverbatim
-
-To create the import .lib files, use the <tt>lib</tt> windows tool (from
-MSVC) the following way to produce simgrid.lib and mingwm10.lib
-\verbatim lib /def:simgrid.def
-lib /def:mingwm10.def
-\endverbatim
-
-If you happen to use Borland C Builder, the right command line is the
-following (note that you don't need any file.def to get this working).
-\verbatim implib simgrid.lib libsimgrid-0.dll
-implib mingwm10.lib mingwm10.dll
-\endverbatim
-
-Then, set the following parameters in Visual C++ 2005:
-Linker -> Input -> Additional dependencies = simgrid.lib mingwm10.lib
-
-Just in case you wonder how to generate a DLL from libtool in another
-project, we added -no-undefined to any lib*_la_LDFLAGS variables so that
-libtool accepts to generate a dynamic library under windows. Then, to make
-it true, we pass any dependencies (such as -lws2 under windows or -lpthread
-on need) on the linking line. Passing such deps is a good idea anyway so
-that they get noted in the library itself, avoiding the users to know about
-our dependencies and put them manually on their compilation line. Then we
-added the AC_LIBTOOL_WIN32_DLL macro just before AC_PROG_LIBTOOL in the
-configure.ac. It means that we exported any symbols which need to be.
-Nowadays, functions get automatically exported, so we don't need to load our
-header files with tons of __declspec(dllexport) cruft. We only need to do so
-for data, but there is no public data in SimGrid so we are good.
+For now,
+we do not feel a real demand for any other language. But if you think there is one,
+ please speak up!
\section faq_howto Feature related questions
Here is the deal. The whole SimGrid project (MSG, SURF, GRAS, ...) is
meant to be kept as simple and generic as possible. We cannot add
-functions for everybody's need when these functions can easily be
+functions for everybody's needs when these functions can easily be
built from the ones already in the API. Most of the time, it is
possible and when it was not possible we always have upgraded the API
accordingly. When somebody asks us a question like "How to do that?
We know. We should add some more examples, but not really some more
complex ones... We should add some examples that illustrate some other
-functionalities (like how to simply encode asynchronous
+functionalists (like how to simply encode asynchronous
communications, RPC, process migrations, thread synchronization, ...)
and we will do it when we will have a little bit more time. We have
tried to document the examples so that they are understandable. Tell
possible. This kind of feature is rather easy to implement by users
and the semantic you associate really depends on people. Having a
*generic* task duplication mechanism is not that trivial (in
-particular because of the data field). That is why I would recommand
+particular because of the data field). That is why I would recommend
that you write it by yourself even if I can give you advice on how to
do it.
-You have the following functions to get informations about a task:
+You have the following functions to get information about a task:
MSG_task_get_name(), MSG_task_get_compute_duration(),
MSG_task_get_remaining_computation(), MSG_task_get_data_size(),
and MSG_task_get_data().
-You could use a dictionnary (#xbt_dict_t) of dynars (#xbt_dynar_t). If
+You could use a dictionary (#xbt_dict_t) of dynars (#xbt_dynar_t). If
you still don't see how to do it, please come back to us...
\subsubsection faq_MIA_asynchronous I want to do asynchronous communications in MSG
-Up until now, there is no asynchronous communications in MSG. However,
-you can create as many process as you want so you should be able to do
-whatever you want... I've written a queue module to help implementing
-some asynchronous communications at low cost (creating thousands of
-process only to handle communications may be problematic in term of
-performance at some point). I'll add it in the distribution asap.
+In the past (version <= 3.4), there was no function to perform asynchronous communications.
+It could easily be implemented by creating new process when needed though. Since version 3.5,
+we have introduced the following functions:
+ - MSG_task_isend()
+ - MSG_task_irecv()
+ - MSG_comm_test()
+ - MSG_comm_wait()
+ - MSG_comm_waitall()
+ - MSG_comm_waitany()
+ - MSG_comm_destroy()
+
+We refer you to the description of these functions for more details on their usage as well
+as to the example section on \ref MSG_ex_asynchronous_communications.
\subsubsection faq_MIA_thread_synchronization I need to synchronize my MSG processes
-You obviously cannot use pthread_mutexes of pthread_conds. The best
-thing would be to propose similar structures. Unfortunately, we
-haven't found time to do it yet. However you can try to play with
-MSG_process_suspend() and MSG_process_resume(). You can even do some
-synchronization with fake communications (using MSG_task_get(),
+You obviously cannot use pthread_mutexes of pthread_conds since we handle every
+scheduling related decision within SimGrid.
+
+In the past (version <=3.3.4) you could do it by playing with
+MSG_process_suspend() and MSG_process_resume() or with fake communications (using MSG_task_get(),
MSG_task_put() and MSG_task_Iprobe()).
+Since version 3.4, you can use classical synchronization structures. See page \ref XBT_synchro or simply check in
+include/xbt/synchro_core.h.
+
\subsubsection faq_MIA_host_load Where is the get_host_load function hidden in MSG?
There is no such thing because its semantic wouldn't be really
communications have an influence on computational power. Should it be taken
into account too?
-First of all, it's near to impossible to predict the load beforehands in the
+First of all, it's near to impossible to predict the load beforehand in the
simulator since it depends on too much parameters (background load
variation, bandwidth sharing algorithmic complexity) some of them even being
-not known beforehands (other task starting at the same time). So, getting
+not known beforehand (other task starting at the same time). So, getting
this information is really hard (just like in real life). It's not just that
we want MSG to be as painful as real life. But as it is in some way
realistic, we face some of the same problems as we would face in real life.
calloc(1,sizeof(double)));
*((double*) task->data) = MSG_get_clock();
MSG_task_put(task, slaves[i % slaves_count], PORT_22);
- INFO0("Send completed");
+ XBT_INFO("Send completed");
return 0;
}
int receiver()
time2 = MSG_get_clock();
if(time1<*((double *)task->data))
time1 = *((double *) task->data);
- INFO1("Communication time : \"%f\" ", time2-time1);
+ XBT_INFO("Communication time : \"%f\" ", time2-time1);
free(task->data);
MSG_task_destroy(task);
return 0;
\subsubsection faq_SG_comm Implementing communication delays between tasks.
-A classic question of SimDag newcommers is about how to express a
+A classic question of SimDag newcomers is about how to express a
communication delay between tasks. The thing is that in SimDag, both
computation and communication are seen as tasks. So, if you want to
model a data dependency between two DAG tasks t1 and t2, you have to
DAG is really the level of abstraction you want to work with, then you should
give a try to \ref SD_API.
-\subsubsection faq_SG Where has SG disappeared?
-
-OK, it's time to explain what's happening to the SimGrid project. Let's
-start with a little bit of history.
-
-* Historically, SimGrid was a low-level toolkit for scheduling with
-classical models such as DAGs. That was SimGrid v.1.* aka SG, written
-by Henri Casanova. I (Arnaud) had been using it in its earliest
-versions during an internship at UCSD.
-
-Then we have realized that encoding distributed algorithm in SG was a
-real pain.
-
-* So we have built MSG on top of SG and have released SimGrid v.2.*. MSG
-offered a very basic API to encode a distributed application easily.
-However encoding MSG on top of SG was not really convenient and did not
-use the DAG part since the control of the task synchronization was done
-on top of MSG and no more in SG. We have been playing a little bit with
-MSG. We have realized that:
-
- \li 1) the platform modeling was quite flexible and could be "almost"
- automated (e.g. using random generator and post-annotations);
-
- \li 2) SG was the bottleneck because of the way we were using
- it. We needed to simulate concurrent transfers, complex load
- sharing mechanisms. Many optimizations (e.g. trace integration)
- were totally inefficient when combined with MSG and made extending SG
- to implement new sharing policies, parallel tasks models, or failures
- (many people were asking for these kind of features) a real pain;
-
- \li 3) the application modeling was not really easy. Even though the
- application modeling depends on people's applications, we thought
- we could improve things here. One of our target here was realistic
-distributed applications ranging from computer sensor networks like
-the NWS to peer-to-peer applications;
-
-* So we have been planning mainly two things for SimGrid 3:
-
- \li 1) I have proposed to get rid of SG and to re-implement a new kernel
- that would be faster and more flexible. That is what I did in the
-end of 2004: SURF. SURF is based on a fast max-min linear solver
-using O(1) data-structures. I have quickly replaced SG by SURF in
-MSG and the result has been that on the MSG example, the new
-version was more than 10 times faster while we had gain a lot of
-flexibility. I think I could still easily make MSG faster but I
-have to work on MSG now (e.g. using some of the O(1)
-data-structures I've been using to build SURF) since it has become
-the bottleneck. Some MSG functions have been removed from the API
-but they were mainly intended to build the platform by hand (they
-had appeared in the earliest versions of MSG) and were therefore
-not useful anymore since we are providing a complete mechanism to
-automatically build the platform and deploy the agents on it.;
-
- \li 2) GRAS is a new project Martin and I have come up with. The idea is
-to have a programming environment that let you program real
-distributed applications while letting you the ability to run it in
-the simulator without having to change the slightest line of your
-code. From the simulation point of view, GRAS performs the
-application modeling automatically... Up until now, GRAS works on
-top MSG for historical reasons but I'm going to make it work
-directly on top of SURF so that it can use all the flex and the
-speed provided by SURF.
-
-Those two things are working, but we want to make everything as clean as
-possible before releasing SimGrid v.3.
-
-So what about those nice DAGs we used to have in SimGrid v.1.? They're
-not anymore in SimGrid v.3. At least not in their original form... Let
-me recall you the way SimGrid 3 is organized:
-
-\verbatim
-________________
-| User code |
-|______________|
-| | MSG | GRAS |
-| -------------|
-| | SURF |
-| -------------|
-| XBT |
-----------------
-\endverbatim
-
-XBT is our tool box and now, you should have an idea of what the other
-ones are. As you can see, the primitive SG is not here
-anymore. However we have written a brand new and cleaner API for this
-purpose: \ref SD_API. It is built directly on top of SURF and provides
-an API rather close to the old SG:
-
-\verbatim
-_________________________
-| User code |
-|________________________|
-| | MSG | GRAS | SimDag |
-| -----------------------|
-| | SURF |
-| -----------------------|
-| XBT |
---------------------------
-\endverbatim
-
-The nice thing is that, as it is writen on top of SURF, it seamlessly
-support DAG of parallel tasks as well as complex communications
-patterns. Some old codes using SG are currently under rewrite using
-\ref SD_API to check that all needful functions are provided.
-
\subsection faq_MIA_generic Generic features
\subsubsection faq_more_processes Increasing the amount of simulated processes
of processes in your simulations.
- <b>A few thousands of simulated processes</b> (soft tricks)\n
- SimGrid can use either pthreads library or the UNIX98 contextes. On
+ SimGrid can use either pthreads library or the UNIX98 contexts. On
most systems, the number of pthreads is limited and then your
simulation may be limited for a stupid reason. This is especially
true with the current linux pthreads, and I cannot get more than
contexts allow me to raise the limit to 25,000 simulated processes
on my laptop.\n\n
The <tt>--with-context</tt> option of the <tt>./configure</tt>
- script allows you to choose between UNIX98 contextes
+ script allows you to choose between UNIX98 contexts
(<tt>--with-context=ucontext</tt>) and the pthread version
(<tt>--with-context=pthread</tt>). The default value is ucontext
when the script detect a working UNIX98 context implementation. On
Windows boxes, the provided value is discarded and an adapted
version is picked up.\n\n
- We experienced some issues with contextes on some rare systems
+ We experienced some issues with contexts on some rare systems
(solaris 8 and lower or old alpha linuxes comes to mind). The main
- problem is that the configure script detect the contextes as being
+ problem is that the configure script detect the contexts as being
functional when it's not true. If you happen to use such a system,
switch manually to the pthread version, and provide us with a good
patch for the configure script so that it is done automatically ;)
- <b>Hundred thousands of simulated processes</b> (hard-core tricks)\n
- As explained above, SimGrid can use UNIX98 contextes to represent
+ As explained above, SimGrid can use UNIX98 contexts to represent
and handle the simulated processes. Thanks to this, the main
limitation to the number of simulated processes becomes the
available memory.\n\n
between 25,000 processes on my laptop (1Gb memory, 1.5Gb swap).\n
- First of all, make sure your code runs for a few hundreds
processes before trying to push the limit. Make sure it's
- valgrind-clean, ie that valgrind does not report neither memory
+ valgrind-clean, i.e. that valgrind does not report neither memory
error nor memory leaks. Indeed, numerous simulated processes
result in *fat* simulation hindering debugging.
- It was really boring to write 25,000 entries in the deployment
file, so I wrote a little script
- <tt>examples/gras/tokenS/make_deployment.pl</tt>, which you may
+ <tt>examples/gras/mutual_exclusion/simple_token/make_deployment.pl</tt>, which you may
want to adapt to your case. You could also think about hijacking
the SURFXML parser (have look at \ref faq_flexml_bypassing).
- The deployment file became quite big, so I had to do what is in
the FAQ entry \ref faq_flexml_limit
- Each UNIX98 context has its own stack entry. As debugging this is
- quite hairly, the default value is a bit overestimated so that
- user don't get into trouble about this. You want to tune this
- size to increse the number of processes. This is the
+ quite hairy, the default value is a bit overestimated so that
+ user doesn't get into trouble about this. You want to tune this
+ size to increase the number of processes. This is the
<tt>STACK_SIZE</tt> define in
- <tt>src/xbt/context_private.h</tt>, which is 128kb by default.
+ <tt>src/xbt/xbt_context_sysv.c</tt>, which is 128kb by default.
Reduce this as much as you can, but be warned that if this value
is too low, you'll get a segfault. The token ring example, which
- is quite simple, runs with 40kb stacks.
+ is quite simple, runs with 40kb stacks.
+ - You may tweak the logs to reduce the stack size further. When
+ logging something, we try to build the string to display in a
+ char array on the stack. The size of this array is constant (and
+ equal to XBT_LOG_BUFF_SIZE, defined in include/xbt/log/h). If the
+ string is too large to fit this buffer, we move to a dynamically
+ sized buffer. In which case, we have to traverse one time the log
+ event arguments to compute the size we need for the buffer,
+ malloc it, and traverse the argument list again to do the actual
+ job.\n
+ The idea here is to move XBT_LOG_BUFF_SIZE to 1, forcing the logs
+ to use a dynamic array each time. This allows us to lower further
+ the stack size at the price of some performance loss...\n
+ This allowed me to run the reduce the stack size to ... 4k. Ie,
+ on my 1Gb laptop, I can run more than 250,000 processes!
\subsubsection faq_MIA_batch_scheduler Is there a native support for batch schedulers in SimGrid?
generic way is thus very hard). However some people have implemented
their own batch schedulers. Vincent Garonne wrote one during his PhD
and put his code in the contrib directory of our SVN so that other can
-keep working on it. You may find inspinring ideas in it.
+keep working on it. You may find inspiring ideas in it.
\subsubsection faq_MIA_checkpointing I need a checkpointing thing
it) fails (cf. #MSG_HOST_FAILURE), then the task can be restarted
from the last checkpoint.\n
-Actually, such a thing does not exists in SimGrid either, but it's just
+Actually, such a thing does not exist in SimGrid either, but it's just
because we don't think it is fundamental and it may be done in the user code
at relatively low cost. You could for example use a watcher that
periodically get the remaining amount of things to do (using
\subsubsection faq_platform_example Where can I find SimGrid platform files?
-There is several little examples in the archive, in the examples/msg
+There are several little examples in the archive, in the examples/msg
directory. From time to time, we are asked for other files, but we
-don't have any at hand right now.
+don't have much at hand right now.
-We do have a description of the Grid'5000 platform, but because of
-some flaws in the current formalism, this file is actually 500Mb,
-which is ways too big to be used in the parser. We have an internship
-currently working on xml syntax improvements which will allow to
-reduce the size of this file and release it.
-
-Once it's done, we plan to model manually other existing platforms the
-same way we did for G5K and also release those files in some sort of
-SimGrid platform catalog project.
+You should refer to the Platform Description Archive
+(http://pda.gforge.inria.fr) project to see the other platform file we
+have available, as well as the Simulacrum simulator, meant to generate
+SimGrid platforms using all classical generation algorithms.
\subsubsection faq_platform_alnem How can I automatically map an existing platform?
<tt>tools/platform_generation/</tt> directory of the SVN. Dinda et Al.
released a very comparable tool, and called it GridG.
-\subsubsection faq_SURF_dynamic Building a dynamic platform, with resource availability
+\subsubsection faq_SURF_multicore Modeling multi-core resources
+
+Since version 3.6 of simgrid we can specify the core number of a resource.
+To use this feature use tag 'host' with 'core' attribute.
+\verbatim
+<?xml version='1.0'?>
+<!DOCTYPE platform SYSTEM "http://simgrid.gforge.inria.fr/simgrid.dtd">
+<platform version="3">
+ <AS id="AS0" routing="Full">
+ <host id="Tremblay" power="98095000" core="6"/>
+ </AS>
+</platform>
+\endverbatim
+
+The specified computing power will be available to up to 6 sequential
+tasks without sharing. If more tasks are placed on this host, the
+resource will be shared accordingly. For example, if you schedule 12
+tasks on the host, each will get half of the computing power. Please
+note that although sound, this model were never scientifically
+assessed. Please keep this fact in mind when using it.
+
+\subsubsection faq_SURF_dynamic Modeling dynamic resource availability
A nice feature of SimGrid is that it enables you to seamlessly have
resources whose availability change over time. When you build a
-platform, you generally declare CPUs like that:
+platform, you generally declare hosts like that:
\verbatim
- <cpu name="Cpu A" power="100.00"/>
+ <host id="host A" power="100.00"/>
\endverbatim
-If you want the availability of "CPU A" to change over time, the only
+If you want the availability of "host A" to change over time, the only
thing you have to do is change this definition like that:
\verbatim
- <cpu name="Cpu A" power="100.00" availability_file="trace_A.txt" state_file="trace_A_failure.txt"/>
+ <host id="host A" power="100.00" availability_file="trace_A.txt" state_file="trace_A_failure.txt"/>
\endverbatim
-For CPUs, availability files are expressed in fraction of available
+For hosts, availability files are expressed in fraction of available
power. Let's have a look at what "trace_A.txt" may look like:
\verbatim
20.0 0.9
\endverbatim
-At time 0, our CPU will deliver 100 flop/s. At time 11.0, it will
-deliver only 50 flop/s until time 20.0 where it will will start
+At time 0, our host will deliver 100 flop/s. At time 11.0, it will
+deliver only 50 flop/s until time 20.0 where it will start
delivering 90 flop/s. Last at time 21.0 (20.0 plus the periodicity
1.0), we'll be back to the beginning and it will deliver 100 flop/s.
\endverbatim
A negative value means "off" while a positive one means "on". At time
-1.0, the CPU is on. At time 1.0, it is turned off and at time 2.0, it
+1.0, the host is on. At time 1.0, it is turned off and at time 2.0, it
is turned on again until time 12 (2.0 plus the periodicity 10.0). It
will be turned on again at time 13.0 until time 23.0, and so on.
links. A usual declaration looks like:
\verbatim
- <network_link name="LinkA" bandwidth="10.0" latency="0.2"/>
+ <link id="LinkA" bandwidth="10.0" latency="0.2"/>
\endverbatim
You have at your disposal the following options: bandwidth_file,
-latency_file and state_file. The only difference with CPUs is that
+latency_file and state_file. The only difference with hosts is that
bandwidth_file and latency_file do not express fraction of available
power but are expressed directly in bytes per seconds and seconds.
-\subsubsection faq_platform_multipath Is it possible to have several paths between two given hosts?
+\subsubsection faq_platform_multipath How to express multipath routing in platform files?
-The answer is no, unfortunately. Let's consider the following platform
-file:
+It is unfortunately impossible to express the fact that there is more
+than one routing path between two given hosts. Let's consider the
+following platform file:
\verbatim
<route src="A" dst="B">
- <route_element name="1"/>
+ <link_ctn id="1"/>
</route>
<route src="B" dst="C">
- <route_element name="2"/>
+ <link_ctn id="2"/>
</route>
<route src="A" dst="C">
- <route_element name="3"/>
+ <link_ctn id="3"/>
</route>
\endverbatim
-Althrough it is perfectly valid, it does not mean that data traveling
+Although it is perfectly valid, it does not mean that data traveling
from A to C can either go directly (using link 3) or through B (using
links 1 and 2). It simply means that the routing on the graph is not
trivial, and that data do not following the shortest path in number of
hops on this graph. Another way to say it is that there is no implicit
in these routing descriptions. The system will only use the routes you
-declare (such as <route src="A" dst="C"><route_element
-name="3"/></route>), without trying to build new routes by aggregating
+declare (such as <route src="A" dst="C"><link_ctn
+id="3"/></route>), without trying to build new routes by aggregating
the provided ones.
You are also free to declare platform where the routing is not
-symetric. For example, add the following to the previous file:
+symmetric. For example, add the following to the previous file:
\verbatim
<route src="C" dst="A">
- <route_element name="2"/>
- <route_element name="1"/>
+ <link_ctn id="2"/>
+ <link_ctn id="1"/>
</route>
\endverbatim
This makes sure that data from C to A go through B where data from A
-to C go directly. Do not worry about realism of such settings since
-we've seen ways more weird situation in real settings.
+to C go directly. Don't worry about realism of such settings since
+we've seen ways more weird situation in real settings (in fact, that's
+the realism of very regular platforms which is questionable, but
+that's another story).
\subsubsection faq_flexml_bypassing Bypassing the XML parser with your own C functions
-So you want to bypass the XML files parser, uh? Maybe doin some parameter
-sweep experiments on your simulations or so? This is possible, but it's not
-really easy. Here is how it goes.
+So you want to bypass the XML files parser, uh? Maybe doing some parameter
+sweep experiments on your simulations or so? This is possible, and
+it's not even really difficult (well. Such a brutal idea could be
+harder to implement). Here is how it goes.
For this, you have to first remember that the XML parsing in SimGrid is done
using a tool called FleXML. Given a DTD, this gives a flex-based parser. If
well-formed SimGrid platform XML file might result in the following
"events":
- - start "platform_description"
- - start "cpu" with attributes name="host1" power="1.0"
- - end "cpu"
- - start "cpu" with attributes name="host2" power="2.0"
- - end "cpu"
- - start "network_link" with ...
- - end "network_link"
- - start "route" with ...
- - end "route"
+ - start "platform_description" with attribute version="2"
+ - start "host" with attributes id="host1" power="1.0"
+ - end "host"
+ - start "host" with attributes id="host2" power="2.0"
+ - end "host"
+ - start "link" with ...
+ - end "link"
- start "route" with ...
+ - start "link_ctn" with ...
+ - end "link_ctn"
- end "route"
- end "platform_description"
The communication from the parser to the SURF code uses two means:
Attributes get copied into some global variables, and a surf-provided
function gets called by the parser for each event. For example, the event
- - start "cpu" with attributes name="host1" power="1.0"
+ - start "host" with attributes id="host1" power="1.0"
-let the parser do the equivalent of:
+let the parser do something roughly equivalent to:
\verbatim
- strcpy("host1",A_cpu_name);
- A_cpu_power = 1.0;
- (*STag_cpu_fun)();
+ strcpy(A_host_id,"host1");
+ A_host_power = 1.0;
+ STag_host();
\endverbatim
In SURF, we attach callbacks to the different events by initializing the
-pointer functions to some the right surf functions. Example in
-workstation_KCCFLN05.c (surf_parse_open() ends up calling surf_parse()):
+pointer functions to some the right surf functions. Since there can be
+more than one callback attached to the same event (if more than one
+model is in use, for example), they are stored in a dynar. Example in
+workstation_ptask_L07.c:
\verbatim
- // Building the routes
+ /* Adding callback functions */
surf_parse_reset_parser();
- STag_route_fun=parse_route_set_endpoints;
- ETag_route_element_fun=parse_route_elem;
- ETag_route_fun=parse_route_set_route;
+ surfxml_add_callback(STag_surfxml_host_cb_list, &parse_cpu_init);
+ surfxml_add_callback(STag_surfxml_prop_cb_list, &parse_properties);
+ surfxml_add_callback(STag_surfxml_link_cb_list, &parse_link_init);
+ surfxml_add_callback(STag_surfxml_route_cb_list, &parse_route_set_endpoints);
+ surfxml_add_callback(ETag_surfxml_link_c_ctn_cb_list, &parse_route_elem);
+ surfxml_add_callback(ETag_surfxml_route_cb_list, &parse_route_set_route);
+
+ /* Parse the file */
surf_parse_open(file);
- xbt_assert1((!surf_parse()),"Parse error in %s",file);
+ xbt_assert(!surf_parse(), "Parse error in %s", file);
surf_parse_close();
\endverbatim
So, to bypass the FleXML parser, you need to write your own version of the
surf_parse function, which should do the following:
- - Call the corresponding STag_<tag>_fun function to simulate tag start
- Fill the A_<tag>_<attribute> variables with the wanted values
+ - Call the corresponding STag_<tag>_fun function to simulate tag start
- Call the corresponding ETag_<tag>_fun function to simulate tag end
- (do the same for the next set of values, and loop)
Then, tell SimGrid that you want to use your own "parser" instead of the stock one:
\verbatim
- surf_parse = surf_parse_bypass;
+ surf_parse = surf_parse_bypass_environment;
MSG_create_environment(NULL);
+ surf_parse = surf_parse_bypass_application;
+ MSG_launch_application(NULL);
\endverbatim
-An example of this trick is distributed in the file examples/msg/masterslave/masterslave_bypass.c
+A set of macros are provided at the end of
+include/surf/surfxml_parse.h to ease the writing of the bypass
+functions. An example of this trick is distributed in the file
+examples/msg/masterslave/masterslave_bypass.c
\section faq_troubleshooting Troubleshooting
\subsection faq_trouble_lib_compil SimGrid compilation and installation problems
-\subsubsection faq_trouble_lib_config ./configure fails!
+\subsubsection faq_trouble_lib_config cmake fails!
-We now only one reason for the configure to fail:
+We know only one reason for the configure to fail:
- - <b>You are using a borken build environment</b>\n
- If symptom is that configure complains about gcc not being able to build
+ - <b>You are using a broken build environment</b>\n
+ If symptom is that the configury magic complains about gcc not being able to build
executables, you are probably missing the libc6-dev package. Damn Ubuntu.
If you experience other kind of issue, please get in touch with us. We are
always interested in improving our portability to new systems.
-\subsubsection faq_trouble_distcheck Dude! "make check" fails on my machine!
+\subsubsection faq_trouble_distcheck Dude! "ctest" fails on my machine!
Don't assume we never run this target, because we do. Check
-http://bob.loria.fr:8010 if you don't believe us.
-
-There is several reasons which may cause the make check to fail on your
-machine:
-
- - <b>You are using a borken libc (probably concerning the contextes)</b>.\n
- The symptom is that the "make check" fails within the examples/msg directory.\n
- By default, SimGrid uses something called ucontexts. This is part of the
- libc, but it's quite undertested. For example, some (old) versions of the
- glibc on alpha do not implement these functions, but provide the stubs
- (which return ENOSYS: not implemented). It may fool our detection mecanism
- and leads to segfaults. There is not much we can do to fix the bug.
- A workaround is to compile with --with-context=pthread to avoid
- ucontext completely. You'll be a bit more limitated in the number
- of simulated processes you can start concurently, but 5000
- processes is still enough for most purposes, isn't it?\n
- This limitation is the reason why we insist on using this piece of ...
- software even if it's so troublesome.\n
- <b>=> use --with-pthread on AMD64 architecture that do not have an
- ultra-recent libc.</b>
-
- - <b>There is a bug in SimGrid we aren't aware of</b>.\n
- If none of the above apply, please drop us a mail on the mailing list so
- that we can check it out. Make sure to read \ref faq_bugrepport
- before you do so.
+http://cdash.inria.fr/CDash/index.php?project=Simgrid (click on
+previous if there is no result for today: results are produced only by
+11am, French time) and
+https://buildd.debian.org/status/logs.php?pkg=simgrid if you don't believe us.
+
+If it's failing on your machine in a way not experienced by the
+autobuilders above, please drop us a mail on the mailing list so that
+we can check it out. Make sure to read \ref faq_bugrepport before you
+do so.
\subsection faq_trouble_compil User code compilation problems
for all the details, but you simply forgot to call one of
XBT_LOG_NEW_DEFAULT_CATEGORY() or XBT_LOG_NEW_DEFAULT_SUBCATEGORY().
-\subsubsection faq_trouble_pthreadstatic "gcc: undefinded reference to pthread_key_create"
+\subsubsection faq_trouble_pthreadstatic "gcc: undefined reference to pthread_key_create"
This indicates that one of the library SimGrid depends on (libpthread
here) was missing on the linking command line. Dependencies of
Actually, the message comes directly from FleXML, the technology on top of
which the parser is built. FleXML has the bad idea of fetching the whole
document in memory before parsing it. And moreover, the memory buffer size
-must be determinded at compilation time.
+must be determined at compilation time.
We use a value which seems big enough for our need without bloating the
simulators footprints. But of course your mileage may vary. In this case,
Flex is recent enough (>= 2.5.31). If not the compilation process should
warn you.
-A while ago, we worked on FleXML to reduce a bit its memory consumtion, but
+A while ago, we worked on FleXML to reduce a bit its memory consumption, but
these issues remain. There is two things we should do:
- use a dynamic buffer instead of a static one so that the only limit
and it breaks the hack we devised to bypass the parser, as explained in
\ref faq_flexml_bypassing. Indeed, this is not a classical usage of the
parser, and Will didn't imagine that we may have used (and even documented)
-such a crude usage of FleXML. So, we now have to repare the bypassing
-functionnality to use the lastest FleXML version and fix the memory usage in
+such a crude usage of FleXML. So, we now have to repair the bypassing
+functionality to use the lastest FleXML version and fix the memory usage in
SimGrid.
\subsubsection faq_trouble_gras_transport GRAS spits networking error messages
Gras, on real platforms, naturally use regular sockets to communicate. They
-are deeply hiden in the gras abstraction, but when things go wrong, you may
+are deeply hidden in the gras abstraction, but when things go wrong, you may
get some weird error messages. Here are some example, with the probable
reason:
- <b>Socket closed by remote side</b>: if the remote process is not
supposed to close the socket at this point, it may be dead.
- - <b>Connection reset by peer</b>: I found this on internet about this
+ - <b>Connection reset by peer</b>: I found this on Internet about this
error. I think it's what's happening here, too:\n
<i>This basically means that a network error occurred while the client was
receiving data from the server. But what is really happening is that the
\subsubsection faq_trouble_errors_big_fat_warning I'm told that my XML files are too old.
-We have decided to change the units in SimGrid. Now we use Bytes, Flops and
-seconds instead of MBytes, MFlops and seconds... Units should be updated
-accordingly and the version of platform_description should be set to a
-valuer greater than 1:
+The format of the XML platform description files is sometimes
+improved. For example, we decided to change the units used in SimGrid
+from MBytes, MFlops and seconds to Bytes, Flops and seconds to ease
+people exchanging small messages. We also reworked the route
+descriptions to allow more compact descriptions.
+
+That is why the XML files are versionned using the 'version' attribute
+of the root tag. Currently, it should read:
\verbatim
- <platform_description version="1">
+ <platform version="2">
\endverbatim
-You should try to use the surfxml_update.pl script that can be found
-<a href="https://gforge.inria.fr/plugins/scmsvn/viewcvs.php/contrib/trunk/platform_generation/?rev=4721&root=simgrid"">here</a>.
-\subsection faq_trouble_valgrind Valgrind-related issues
+If your files are too old, you can use the simgrid_update_xml.pl
+script which can be found in the tools directory of the archive.
+
+\subsection faq_trouble_valgrind Valgrind-related and other debugger issues
If you don't, you really should use valgrind to debug your code, it's
almost magic.
-\subsubsection faq_trouble_vg_context Stack switching problems and truncated backtraces
-
-With the default version of simgrid, valgrind will probably spit tons
-of warnings about stack switching like the following, and produce
-truncated bactraces where only one call appears instead of the whole
-stack.
-
-\verbatim
-==14908== Warning: client switching stacks? SP change: 0xBEA2A48C --> 0x476F350
-==14908== to suppress, use: --max-stackframe=1171541700 or greater
-==14908== Warning: client switching stacks? SP change: 0x476E1E4 --> 0xBEA2A48C
-==14908== to suppress, use: --max-stackframe=1171537240 or greater
-==14908== Warning: client switching stacks? SP change: 0xBEA2A48C --> 0x4792420
-==14908== to suppress, use: --max-stackframe=1171685268 or greater
-==14908== further instances of this message will not be shown.
-\endverbatim
-
-This is because valgrind don't like too much the UNIX98 contextes we
-use by default in simgrid for efficiency reasons. Simply add the
---with-pthread flag to your configure when debugging your code. You
-may also find --disable-compiler-optimization usefull if valgrind or
-gdb get fooled by the optimization done by the compiler. But you
-should remove these flages when everything works before going in
-production (before launching your 1252135 experiments), or everything
-will run only one third of the true SimGrid potential.
-
\subsubsection faq_trouble_vg_longjmp longjmp madness in valgrind
This is when valgrind starts complaining about longjmp things, just like:
==21434== at 0x420DC3A: __longjmp (__longjmp.S:48)
\endverbatim
-or even when it reports scary things like:
-
-\verbatim ==24023== Warning: client switching stacks? SP change: 0xBE3FF618 --> 0xBE7FF710
-x86->IR: unhandled instruction bytes: 0xF4 0xC7 0x83 0xD0
-==24023== to suppress, use: --max-stackframe=4194552 or greater
-==24023== Your program just tried to execute an instruction that Valgrind
-==24023== did not recognise. There are two possible reasons for this.
-==24023== 1. Your program has a bug and erroneously jumped to a non-code
-==24023== location. If you are running Memcheck and you just saw a
-==24023== warning about a bad jump, it's probably your program's fault.
-==24023== 2. The instruction is legitimate but Valgrind doesn't handle it,
-==24023== i.e. it's Valgrind's fault. If you think this is the case or
-==24023== you are not sure, please let us know.
-==24023== Either way, Valgrind will now raise a SIGILL signal which will
-==24023== probably kill your program.
-==24023==
-==24023== Process terminating with default action of signal 4 (SIGILL)
-==24023== Illegal opcode at address 0x420D234
-==24023== at 0x420D234: abort (abort.c:124)
-\endverbatim
-
This is the sign that you didn't used the exception mecanism well. Most
probably, you have a <tt>return;</tt> somewhere within a <tt>TRY{}</tt>
block. This is <b>evil</b>, and you must not do this. Did you read the section
\verbatim export VALGRIND_OPTS="--leak-check=yes --leak-resolution=high --num-callers=40 --tool=memcheck --suppressions=$HOME/.valgrind.supp" \endverbatim
+\subsubsection faq_trouble_backtraces Truncated backtraces
+
+When debugging SimGrid, it's easier to pass the
+--disable-compiler-optimization flag to the configure if valgrind or
+gdb get fooled by the optimization done by the compiler. But you
+should remove these flag when everything works before going in
+production (before launching your 1252135 experiments), or everything
+will run only one half of the true SimGrid potential.
+
\subsection faq_deadlock There is a deadlock in my code!!!
Unfortunately, we cannot debug every code written in SimGrid. We
http://www.chiark.greenend.org.uk/~sgtatham/bugs.html (it is not SimGrid
specific at all, but it's full of good advices).
-\author Arnaud Legrand (arnaud.legrand::imag.fr)
-\author Martin Quinson (martin.quinson::loria.fr)
-
+\author Da SimGrid team <simgrid-devel@lists.gforge.inria.fr>
*/
+******************************************************************
+* OLD CRUFT NOT USED ANYMORE *
+******************************************************************
+
+
+subsection faq_crosscompile Cross-compiling a Windows DLL of SimGrid from linux
+
+At the moment, we do not distribute Windows pre-compiled version of SimGrid
+because the support for this platform is still experimental. We know that
+some parts of the GRAS environment do not work, and we think that the others
+environments (MSG and SD) have good chances to work, but we didn't test
+ourselves. This section explains how we generate the SimGrid DLL so that you
+can build it for yourself. First of all, you need to have a version more
+recent than 3.1 (ie, a SVN version as time of writting).
+
+In order to cross-compile the package to windows from linux, you need to
+install mingw32 (minimalist gnu win32). On Debian, you can do so by
+installing the packages mingw32 (compiler), mingw32-binutils (linker and
+so), mingw32-runtime.
+
+You can use the VPATH support of configure to compile at the same time for
+linux and windows without dupplicating the source nor cleaning the tree
+between each. Just run bootstrap (if you use the SVN) to run the autotools.
+Then, create a linux and a win directories. Then, type:
+\verbatim cd linux; ../configure --srcdir=.. <usual configure flags>; make; cd ..
+cd win; ../configure --srcdir=.. --host=i586-mingw32msvc <flags>; make; cd ..
+\endverbatim
+The trick to VPATH builds is to call configure from another directory,
+passing it an extra --srcdir argument to tell it where all the sources are.
+It will understand you want to use VPATH. Then, the trick to cross-compile
+is simply to add a --host argument specifying the target you want to build
+for. The i586-mingw32msvc string is what you have to pass to use the mingw32
+environment as distributed in Debian.
+
+After that, you can run all make targets from both directories, and test
+easily that what you change for one arch does not break the other one.
+
+It is possible that this VPATH build thing breaks from time to time in the
+SVN since it's quite fragile, but it's granted to work in any released
+version. If you experience problems, drop us a mail.
+
+Another possible source of issue is that at the moment, building the
+examples request to use the gras_stub_generator tool, which is a compiled
+program, not a script. In cross-compilation, you need to cross-execute with
+wine for example, which is not really pleasant. We are working on this, but
+in the meanwhile, simply don't build the examples in cross-compilation
+(<tt>cd src</tt> before running make).
+
+Program (cross-)compiled with mingw32 do request an extra DLL at run-time to be
+usable. For example, if you want to test your build with wine, you should do
+the following to put this library where wine looks for DLLs.
+\verbatim
+cp /usr/share/doc/mingw32-runtime/mingwm10.dll.gz ~/.wine/c/windows/system/
+gunzip ~/.wine/c/windows/system/mingwm10.dll.gz
+\endverbatim
+
+The DLL is built in src/.libs, and installed in the <i>prefix</i>/bin directory
+when you run make install.
+
+If you want to use it in a native project on windows, you need to use
+simgrid.dll and mingwm10.dll. For each DLL, you need to build .def file
+under linux (listing the defined symbols), and convert it into a .lib file
+under windows (specifying this in a way that windows compilers like). To
+generate the def files, run (under linux):
+\verbatim echo "LIBRARY libsimgrid-0.dll" > simgrid.def
+echo EXPORTS >> simgrid.def
+nm libsimgrid-0.dll | grep ' T _' | sed 's/.* T _//' >> simgrid.def
+nm libsimgrid-0.dll | grep ' D _' | sed 's/.* D _//' | sed 's/$/ DATA/' >> simgrid.def
+
+echo "LIBRARY mingwm10.dll" > mingwm10.def
+echo EXPORTS >> mingwm10.def
+nm mingwm10.dll | grep ' T _' | sed 's/.* T _//' >> mingwm10.def
+nm mingwm10.dll | grep ' D _' | sed 's/.* D _//' | sed 's/$/ DATA/' >> mingwm10.def
+\endverbatim
+
+To create the import .lib files, use the <tt>lib</tt> windows tool (from
+MSVC) the following way to produce simgrid.lib and mingwm10.lib
+\verbatim lib /def:simgrid.def
+lib /def:mingwm10.def
+\endverbatim
+
+If you happen to use Borland C Builder, the right command line is the
+following (note that you don't need any file.def to get this working).
+\verbatim implib simgrid.lib libsimgrid-0.dll
+implib mingwm10.lib mingwm10.dll
+\endverbatim
+
+Then, set the following parameters in Visual C++ 2005:
+Linker -> Input -> Additional dependencies = simgrid.lib mingwm10.lib
+
+Just in case you wonder how to generate a DLL from libtool in another
+project, we added -no-undefined to any lib*_la_LDFLAGS variables so that
+libtool accepts to generate a dynamic library under windows. Then, to make
+it true, we pass any dependencies (such as -lws2 under windows or -lpthread
+on need) on the linking line. Passing such deps is a good idea anyway so
+that they get noted in the library itself, avoiding the users to know about
+our dependencies and put them manually on their compilation line. Then we
+added the AC_LIBTOOL_WIN32_DLL macro just before AC_PROG_LIBTOOL in the
+configure.ac. It means that we exported any symbols which need to be.
+Nowadays, functions get automatically exported, so we don't need to load our
+header files with tons of __declspec(dllexport) cruft. We only need to do so
+for data, but there is no public data in SimGrid so we are good.
