X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/c5c447226e4b526926a548757f9f5d539530ef82..9d5492041a839402b7c142c08ebdc8df6e9d5c24:/doc/FAQ.doc diff --git a/doc/FAQ.doc b/doc/FAQ.doc index 60eba33098..42e6649d16 100644 --- a/doc/FAQ.doc +++ b/doc/FAQ.doc @@ -1,4 +1,4 @@ -/*! \page faq Frequently Asked Questions +/*! \page FAQ Frequently Asked Questions \htmlinclude .FAQ.doc.toc @@ -36,30 +36,10 @@ on their own. The difference between both is that MSG is somehow easier to use, but GRAS is not limited 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 beginning 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... +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 @@ -72,21 +52,23 @@ filter (e.g. with bash): ./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 section \ref faq_tracing. +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 link 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! +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 @@ -149,11 +131,11 @@ As we already told, we prefer keeping the API as simple as 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(). @@ -175,7 +157,7 @@ we have introduced the following functions: - MSG_comm_destroy() We refer you to the description of these functions for more details on their usage as well -as to the exemple section on \ref MSG_ex_asynchronous_communications. +as to the example section on \ref MSG_ex_asynchronous_communications. \subsubsection faq_MIA_thread_synchronization I need to synchronize my MSG processes @@ -203,10 +185,10 @@ even take the currently running tasks into account. In some SURF models, 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. @@ -337,7 +319,7 @@ Here are a few tricks you can apply if you want to increase the amount of processes in your simulations. - A few thousands of simulated processes (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 @@ -345,21 +327,21 @@ of processes in your simulations. contexts allow me to raise the limit to 25,000 simulated processes on my laptop.\n\n The --with-context option of the ./configure - script allows you to choose between UNIX98 contextes + script allows you to choose between UNIX98 contexts (--with-context=ucontext) and the pthread version (--with-context=pthread). 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 ;) - Hundred thousands of simulated processes (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 @@ -367,7 +349,7 @@ of processes in your simulations. 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 @@ -378,9 +360,9 @@ of processes in your simulations. - 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 STACK_SIZE define in src/xbt/xbt_context_sysv.c, which is 128kb by default. Reduce this as much as you can, but be warned that if this value @@ -434,7 +416,7 @@ completion) to be saved somewhere. So if a host (and the task executing on 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 @@ -445,7 +427,7 @@ subtasks. \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 much at hand right now. @@ -481,35 +463,25 @@ released a very comparable tool, and called it GridG. \subsubsection faq_SURF_multicore Modeling multi-core resources -There is currently no native support for multi-core or SMP machines in -SimGrid. We are currently working on it, but coming up with the right -model is very hard: Cores share caches and bus to access memory and -thus interfere with each others. Memory contention is a crucial -component of multi-core modeling. - -In the meanwhile, some user-level tricks can reveal sufficient for -you. For example, you may model each core by a CPU and add some very -high speed links between them. This complicates a bit the user code -since you have to remember that when you assign something to a (real) -host, it can be any of the (fake) hosts representing the cores of a -given machine. For that, you can use the prop tag of the XML files as -follows. Your code should then look at the ‘machine’ property -associated with each workstation, and run parallel tasks over all -cores of the machine. - +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 - - - - - - - - - - + + + + + + + \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 @@ -538,7 +510,7 @@ PERIODICITY 1.0 \endverbatim 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 will start +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. @@ -574,13 +546,13 @@ following platform file: \verbatim - + - + - + \endverbatim @@ -590,7 +562,7 @@ 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"><link:ctn +declare (such as <route src="A" dst="C"><link_ctn id="3"/></route>), without trying to build new routes by aggregating the provided ones. @@ -599,8 +571,8 @@ symmetric. For example, add the following to the previous file: \verbatim - - + + \endverbatim @@ -635,8 +607,8 @@ well-formed SimGrid platform XML file might result in the following - start "link" with ... - end "link" - start "route" with ... - - start "link:ctn" with ... - - end "link:ctn" + - start "link_ctn" with ... + - end "link_ctn" - end "route" - end "platform_description" @@ -693,762 +665,6 @@ 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 -\subsection faq_simgrid_configuration Changing SimGrid's behavior - -A number of options can be given at runtime to change the default -SimGrid behavior. In particular, you can change the default cpu and -network models... - -\subsubsection faq_simgrid_configuration_fullduplex Using Fullduplex - -Experimental fullduplex support is now available on the svn branch. In order to fullduple to work your platform must have two links for each pair -of interconnected hosts, see an example here: -\verbatim - simgrid_svn_sources/exemples/msg/gtnets/fullduplex-p.xml -\endverbatim - -Using fullduplex support ongoing and incoming communication flows are -treated independently for most models. The exception is the LV08 model which -adds 0.05 of usage on the opposite direction for each new created flow. This -can be useful to simulate some important TCP phenomena such as ack compression. - -Running a fullduplex example: -\verbatim - cd simgrid_svn_sources/exemples/msg/gtnets - ./gtnets fullduplex-p.xml fullduplex-d.xml --cfg=fullduplex:1 -\endverbatim - - - - - -\subsubsection faq_simgrid_configuration_gtnets Using GTNetS - -It is possible to use a packet-level network simulator -instead of the default flow-based simulation. You may want to use such -an approach if you have doubts about the validity of the default model -or if you want to perform some validation experiments. At the moment, -we support the GTNetS simulator (it is still rather experimental -though, so leave us a message if you play with it). - - - -To enable GTNetS model inside SimGrid it is needed to patch the GTNetS simulator source code -and build/install it from scratch - - - - Download and enter the recent downloaded GTNetS directory - - \verbatim - svn checkout svn://scm.gforge.inria.fr/svn/simgrid/contrib/trunk/GTNetS/ - cd GTNetS - \endverbatim - - - - Use the following commands to unzip and patch GTNetS package to work within SimGrid. - - \verbatim - unzip gtnets-current.zip - tar zxvf gtnets-current-patch.tgz - cd gtnets-current - cat ../00*.patch | patch -p1 - \endverbatim - - - OPTIONALLY you can use a patch for itanium 64bit processor family. - - \verbatim - cat ../AMD64-FATAL-Removed-DUL_SIZE_DIFF-Added-fPIC-compillin.patch | patch -p1 - \endverbatim - - - Compile GTNetS - - 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. - - - \verbatim - ln -sf Makefile.linux Makefile - make depend - make debug - \endverbatim - - - - NOTE A lot of warnings are expected but the application should compile - just fine. If the makefile insists in compiling some QT libraries - please try a make clean before asking for help. - - - - To compile optimized version - - \verbatim - make opt - \endverbatim - - - - Installing GTNetS - - 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. - - \verbatim - ln -sf //gtnets_current/libgtsim-debug.so //usr/lib/libgtnets.so - export LD_LIBRARY_PATH=$LD_LIBRARY_PATH://usr/lib/libgtnets.so - mkdir //usr/include/gtnets - cp -fr SRC/*.h //usr/include/gtnets - \endverbatim - - - - Enable GTNetS support in SimGrid - -In order to enable gtnets with simgrid you have to give where is gtnets. (path to \/lib and \/include) - - \verbatim - Since v3.4 (with cmake) - cmake . -Dgtnets_path=//usr - - Until v3.4 (with autotools) - ./configure --with-gtnets=//usr - \endverbatim - - - Once you have followed all the instructions for compiling and - installing successfully you can activate this feature at - runntime with the following options: - - \verbatim - Since v3.4 (with cmake) - cd simgrid - make - ctest -R gtnets - - Until v3.4 (with autotools) - cd simgrid/example/msg/ - make - make check - \endverbatim - - - - Or try the GTNetS model dogbone example with - - \verbatim - gtnets/gtnets gtnets/onelink-p.xml gtnets/onelink-d.xml --cfg=network_model:GTNets - \endverbatim - - - A long version of this HowTo it is available - - - More about GTNetS simulator at GTNetS Website - - - - DISCLAIMER - The patches provided by us worked successfully with GTNetS found - here, - dated from 12th June 2008. Due to the discontinuing development of - GTNetS it is impossible to precise a version number. We STRONGLY recommend you - to download and install the GTNetS version found in SimGrid repository as explained above. - - - - -\subsubsection faq_simgrid_configuration_alternate_network Using alternative flow models - -The default simgrid network model uses a max-min based approach as -explained in the research report -A Network Model for Simulation of Grid Application. -Other models have been proposed and implemented since then (see for example -Accuracy Study and Improvement of Network Simulation in the SimGrid Framework) -and can be activated at runtime. For example: -\verbatim -./mycode platform.xml deployment.xml --cfg=workstation/model:compound --cfg=network/model:LV08 -cfg=cpu/model:Cas01 -\endverbatim - -Possible models for the network are currently "Constant", "CM02", -"LegrandVelho", "GTNets", Reno", "Reno2", "Vegas". Others will -probably be added in the future and many of the previous ones are -experimental and are likely to disappear without notice... To know the -list of the currently implemented models, you should use the ---help-models command line option. - -\verbatim -./masterslave_forwarder ../small_platform.xml deployment_masterslave.xml --help-models -Long description of the workstation models accepted by this simulator: - CLM03: Default workstation model, using LV08 and CM02 as network and CPU - compound: Workstation model allowing you to use other network and CPU models - ptask_L07: Workstation model with better parallel task modeling -Long description of the CPU models accepted by this simulator: - Cas01_fullupdate: CPU classical model time=size/power - Cas01: Variation of Cas01_fullupdate with partial invalidation optimization of lmm system. Should produce the same values, only faster - CpuTI: Variation of Cas01 with also trace integration. Should produce the same values, only faster if you use availability traces -Long description of the network models accepted by this simulator: - Constant: Simplistic network model where all communication take a constant time (one second) - CM02: Realistic network model with lmm_solve and no correction factors - LV08: Realistic network model with lmm_solve and these correction factors: latency*=10.4, bandwidth*=.92, S=8775 - Reno: Model using lagrange_solve instead of lmm_solve (experts only) - Reno2: Model using lagrange_solve instead of lmm_solve (experts only) - Vegas: Model using lagrange_solve instead of lmm_solve (experts only) -\endverbatim - -\subsection faq_tracing Tracing Simulations for Visualization - -The trace visualization is widely used to observe and understand the behavior -of parallel applications and distributed algorithms. Usually, this is done in a -two-step fashion: the user instruments the application and the traces are -analyzed after the end of the execution. The visualization itself can highlights -unexpected behaviors, bottlenecks and sometimes can be used to correct -distributed algorithms. The SimGrid team has instrumented the library -in order to let users trace their simulations and analyze them. This part of the -user manual explains how the tracing-related features can be enabled and used -during the development of simulators using the SimGrid library. - -\subsubsection faq_tracing_howitworks How it works - -For now, the SimGrid library is instrumented so users can trace the platform -utilization using the MSG, SimDAG and SMPI interface. This means that the tracing will -register how much power is used for each host and how much bandwidth is used for -each link of the platform. The idea with this type of tracing is to observe the -overall view of resources utilization in the first place, especially the -identification of bottlenecks, load-balancing among hosts, and so on. - -The idea of the tracing facilities is to give SimGrid users to possibility to -classify MSG and SimDAG tasks by category, tracing the platform utilization -(hosts and links) for each of the categories. For that, -the tracing interface enables the declaration of categories and a function to -mark a task with a previously declared category. The tasks that are not -classified according to a category are not traced. Even if the user -does not specify any category, the simulations can still be traced in terms -of resource utilization by using a special parameter that is detailed below. - -\subsubsection faq_tracing_enabling Enabling using CMake - -With the sources of SimGrid, it is possible to enable the tracing -using the parameter -Denable_tracing=ON when the cmake is executed. -The section \ref faq_tracing_functions describes all the functions available -when this Cmake options is activated. These functions will have no effect -if SimGrid is configured without this option (they are wiped-out by the -C-preprocessor). - -\verbatim -$ cmake -Denable_tracing=ON . -$ make -\endverbatim - -\subsubsection faq_tracing_functions Tracing Functions - -\li \c TRACE_category (const char *category): This function should be used -to define a user category. The category can be used to differentiate the tasks -that are created during the simulation (for example, tasks from server1, -server2, or request tasks, computation tasks, communication tasks). -All resource utilization (host power and link bandwidth) will be -classified according to the task category. Tasks that do not belong to a -category are not traced. The color for the category that is being declared -is random (use next function to specify a color). - -\li \c TRACE_category_with_color (const char *category, const char *color): Same -as TRACE_category, but let user specify a color encoded as a RGB-like string with -three floats from 0 to 1. So, to specify a red color, the user can pass "1 0 0" as -color parameter. A light-gray color can be specified using "0.7 0.7 0.7" as color. - -\li \c TRACE_msg_set_task_category (m_task_t task, const char *category): -This function should be called after the creation of a MSG task, to define the -category of that task. The first parameter \c task must contain a task that was -created with the function \c MSG_task_create. The second parameter -\c category must contain a category that was previously defined by the function -\c TRACE_category. - -\li \c TRACE_sd_set_task_category (SD_task_t task, const char *category): -This function should be called after the creation of a SimDAG task, to define the -category of that task. The first parameter \c task must contain a task that was -created with the function \c MSG_task_create. The second parameter -\c category must contain a category that was previously defined by the function -\c TRACE_category. - -\li \c TRACE_[host|link]_variable_declare (const char *variable): -Declare a user variable that will be associated to host/link. A variable can -be used to trace user variables such as the number of tasks in a server, -the number of clients in an application (for hosts), and so on. - -\li \c TRACE_[host|link]_variable_[set|add|sub] (const char *[host|link], const char *variable, double value): -Set the value of a given user variable for a given host/link. The value -of this variable is always associated to the host/link. The host/link -parameters should be its name as the one listed in the platform file. - -\li \c TRACE_[host|link]_variable_[set|add|sub]_with_time (double time, const char *[host|link], const char *variable, double value): -Same as TRACE_[host|link]_variable_[set|add|sub], but let user specify -the time used to trace it. Users can specify a time that is not the -simulated clock time as defined by the core simulator. This allows -a fine-grain control of time definition, but should be used with -caution since the trace can be inconsistent if resource utilization -traces are also traced. - -\li \c TRACE_link_srcdst_variable_[set|add|sub] (const char *src, const char *dst, const char *variable, double value): -Same as TRACE_link_variable_[set|add|sub], but now users specify a source and -destination hosts (as the names from the platform file). The tracing library -will get the corresponding route that connects those two hosts (src and dst) and -[set|add|sub] the value's variable for all the links of the route. - -\li \c TRACE_link_srcdst_variable_[set|add|sub]_with_time (double time, const char *src, const char *dst, const char *variable, double value): -Same as TRACE_link_srcdst_variable_[set|add|sub], but user specify a time different from the simulated time. - -\subsubsection faq_tracing_options Tracing configuration Options - -These are the options accepted by the tracing system of SimGrid: - -\li \c -tracing -: - Safe switch. It activates (or deactivates) the tracing system. - No other tracing options take effect if this one is not activated. - -\li \c -tracing/platform -: - Register the simulation platform in the trace file. - -\li \c -tracing/onelink_only -: - By default, the tracing system uses all routes in the platform file - to re-create a "graph" of the platform and register it in the trace file. - This option let the user tell the tracing system to use only the routes - that are composed with just one link. - -\li \c -tracing/categorized -: - It activates the categorized resource utilization tracing. It should - be enabled if tracing categories are used by this simulator. - -\li \c -tracing/uncategorized -: - It activates the uncategorized resource utilization tracing. Use it if - this simulator do not use tracing categories and resource use have to be - traced. - -\li \c -tracing/filename -: - A file with this name will be created to register the simulation. The file - is in the Paje format and can be analyzed using Triva or Paje visualization - tools. More information can be found in these webpages: - http://triva.gforge.inria.fr/ - http://paje.sourceforge.net/ - -\li \c -tracing/smpi -: - This option only has effect if this simulator is SMPI-based. Traces the MPI - interface and generates a trace that can be analyzed using Gantt-like - visualizations. Every MPI function (implemented by SMPI) is transformed in a - state, and point-to-point communications can be analyzed with arrows. - -\li \c -tracing/smpi/group -: - This option only has effect if this simulator is SMPI-based. The processes - are grouped by the hosts where they were executed. - -\li \c -tracing/msg/task -: - This option only has effect if this simulator is MSG-based. It traces the - behavior of all categorized MSG tasks, grouping them by hosts. - -\li \c -tracing/msg/process -: - This option only has effect if this simulator is MSG-based. It traces the - behavior of all categorized MSG processes, grouping them by hosts. This option - can be used to track process location if this simulator has process migration. - - -\li \c -triva/categorized:graph_categorized.plist -: - This option generates a graph configuration file for Triva considering - categorized resource utilization. - -\li \c -triva/uncategorized:graph_uncategorized.plist -: - This option generates a graph configuration file for Triva considering - uncategorized resource utilization. - -\subsubsection faq_tracing_example Example of Instrumentation - -A simplified example using the tracing mandatory functions. - -\verbatim -int main (int argc, char **argv) -{ - MSG_global_init (&argc, &argv); - - //(... after deployment ...) - - //note that category declaration must be called after MSG_create_environment - TRACE_category_with_color ("request", "1 0 0"); - TRACE_category_with_color ("computation", "0.3 1 0.4"); - TRACE_category ("finalize"); - - m_task_t req1 = MSG_task_create("1st_request_task", 10, 10, NULL); - m_task_t req2 = MSG_task_create("2nd_request_task", 10, 10, NULL); - m_task_t req3 = MSG_task_create("3rd_request_task", 10, 10, NULL); - m_task_t req4 = MSG_task_create("4th_request_task", 10, 10, NULL); - TRACE_msg_set_task_category (req1, "request"); - TRACE_msg_set_task_category (req2, "request"); - TRACE_msg_set_task_category (req3, "request"); - TRACE_msg_set_task_category (req4, "request"); - - m_task_t comp = MSG_task_create ("comp_task", 100, 100, NULL); - TRACE_msg_set_task_category (comp, "computation"); - - m_task_t finalize = MSG_task_create ("finalize", 0, 0, NULL); - TRACE_msg_set_task_category (finalize, "finalize"); - - //(...) - - MSG_clean(); - return 0; -} -\endverbatim - -\subsubsection faq_tracing_analyzing Analyzing the SimGrid Traces - -The SimGrid library, during an instrumented simulation, creates a trace file in -the Paje file format that contains the platform utilization for the simulation -that was executed. The visualization analysis of this file is performed with the -visualization tool Triva, with -special configurations tunned to SimGrid needs. This part of the documentation -explains how to configure and use Triva to analyse a SimGrid trace file. - -- Installing Triva: the tool is available in the INRIAGforge, -at http://triva.gforge.inria.fr. -Use the following command to get the sources, and then check the file -INSTALL. This file contains instructions to install -the tool's dependencies in a Ubuntu/Debian Linux. The tool can also -be compiled in MacOSes natively, check INSTALL.mac file. -\verbatim -$ svn checkout svn://scm.gforge.inria.fr/svn/triva -$ cd triva -$ cat INSTALL -\endverbatim - -- Executing Triva: a binary called Triva is available after the - installation (you can execute it passing --help to check its -options). If the triva binary is not available after following the -installation instructions, you may want to execute the following command to -initialize the GNUstep environment variables. We strongly recommend that you -use the latest GNUstep packages, and not the packages available through apt-get -in Ubuntu/Debian packaging systems. If you install GNUstep using the latest -available packages, you can execute this command: -\verbatim -$ source /usr/GNUstep/System/Library/Makefiles/GNUstep.sh -\endverbatim -You should be able to see this output after the installation of triva: -\verbatim -$ ./Triva.app/Triva --help -Usage: Triva [OPTIONS...] TRACE0 [TRACE1] -Trace Analysis through Visualization - -TimeInterval - --ti_frequency {double} Animation: frequency of updates - --ti_hide Hide the TimeInterval window - --ti_forward {double} Animation: value to move time-slice - --ti_apply Apply the configuration - --ti_update Update on slider change - --ti_animate Start animation - --ti_start {double} Start of time slice - --ti_size {double} Size of time slice -Triva - --comparison Compare Trace Files (Experimental) - --graph Configurable Graph - --list Print Trace Type Hierarchy - --hierarchy Export Trace Type Hierarchy (dot) - --stat Trace Statistics and Memory Utilization - --instances List All Trace Entities - --linkview Link View (Experimental) - --treemap Squarified Treemap - --merge Merge Trace Files (Experimental) - --check Check Trace File Integrity -GraphConfiguration - --gc_conf {file} Graph Configuration in Property List Format - --gc_apply Apply the configuration - --gc_hide Hide the GraphConfiguration window -\endverbatim -Triva expects that the user choose one of the available options -(currently --graph or --treemap for a visualization analysis) -and the trace file from the simulation. - -- Understanding Triva - time-slice: the analysis of a trace file using - the tool always takes into account the concept of the time-slice. -This concept means that what is being visualized in the screen is always -calculated considering a specific time frame, with its beggining and end -timestamp. The time-slice is configured by the user and can be changed -dynamically through the window called Time Interval that is opened -whenever a trace file is being analyzed. The next figure depicts the time-slice -configuration window. -In the top of the window, in the space named Trace Time, -the two fields show the beggining of the trace (which usually starts in 0) and -the end (that depends on the time simulated by SimGrid). The middle of the -window, in the square named Time Slice Configuration, contains the -aspects related to the time-slice, including its start and its -size. The gray rectangle in the bottom of this part indicates the -current time-slice that is considered for the drawings. If the checkbox -Update Drawings on Sliders Change is not selected, the button -Apply must be clicked in order to inform triva that the -new time-slice must be considered. The bottom part of the window, in the space -indicated by the square Time Slice Animation can be used to advance -the time-frame automatically. The user configures the amount of time that the -time-frame will forward and how frequent this update will happen. Once this is -configured, the user clicks the Play button in order to see the dynamic -changes on the drawings. -
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-Remarks: when the trace has too many hosts or links, the computation to -take into account a new time-slice can be expensive. When this happens, the -Frequency parameter, but also updates caused by change on configurations -when the checkbox Update Drawings on Sliders -Change is selected will not be followed. - -- Understanding Triva - graph: this part of the documention explains how - to analyze the traces using the graph view of Triva, when the user executes -the tool passing --graph as parameter. Triva opens three windows when -this parameter is used: the Time Interval window (previously described), -the Graph Representation window, and the Graph Configuration -window. The Graph Representation is the window where drawings take place. -Initially, it is completely white waiting for a proper graph configuration input -by the user. We start the description of this type of analysis by describing the -Graph Configuration window (depicted below). By using a particular -configuration, triva -can be used to customize the graph drawing according to -the SimGrid trace that was created with user-specific categories. Before delving -into the details of this customization, let us first explain the major parts of -the graph configuration window. The buttons located in the top-right corner can -be used to delete, copy and create a new configuration. The checkbox in the -top-middle part of the window indicates if the configuration typed in the -textfield is syntactically correct (we are using the non-XML -Property List Format to -describe the configuration). The pop-up button located on the top-left corner -indicates the selected configuration (the user can have multiple graph -configurations). The bottom-left text field contains the name of the current -configuration (updates on this field must be followed by typing enter on the -keyboard to take into account the name change). The bottom-right Apply -button activates the current configuration, resulting on an update on the graph -drawings. -
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-Basic SimGrid Configuration: The figure shows in the big textfield the -basic configuration that should be used during the analysis of a SimGrid trace -file. The basic logic of the configuration is as follows: -\verbatim -{ - node = (HOST); - edge = (LINK); -\endverbatim -The nodes of the graph will be created based on the node parameter, which -in this case is the different "HOST"s of the platform -used to simulate. The edge parameter indicates that the edges of the -graph will be created based on the "LINK"s of the platform. After the -definition of these two parameters, the configuration must detail how -HOSTs and LINKs should be drawn. For that, the configuration -must have an entry for each of the types used. For HOST, as basic -configuration, we have: -\verbatim - HOST = { - size = power; - scale = global; - }; -\endverbatim -The parameter size indicates which variable from the trace file will be -used to define the size of the node HOST in the visualization. If the simulation -was executed with availability traces, the size of the nodes will be changed -according to these traces. The parameter scale indicates if the value -of the variable is global or local. If it is global, the value -will be relative to the power of all other hosts, if it is local, the value will -be relative locally. -For LINK we have: -\verbatim - LINK = { - src = source; - dst = destination; - - size = bandwidth; - scale = global; - }; -\endverbatim -For the types specified in the edge parameter (such as LINK), -the configuration must contain two additional parameters: src and -dst that are used to properly identify which nodes this edge is -connecting. The values source and destination are always present -in the SimGrid trace file and should not be changed in the configuration. The -parameter size for the LINK, in this case, is configured as the -variable bandwidth, with a global scale. The scale meaning -here is exactly the same used for nodes. The last parameter is the GraphViz -algorithm used to calculate the position of the nodes in the graph -representation. -\verbatim - graphviz-algorithm = neato; -} -\endverbatim -Customizing the Graph Representation: triva is capable to handle -a customized graph representation based on the variables present in the trace -file. In the case of SimGrid, every time a category is created for tasks, two -variables in the trace file are defined: one to indicate node utilization (how -much power was used by that task category), and another to indicate link -utilization (how much bandwidth was used by that category). For instance, if the -user declares a category named request, there will be variables named -prequest and a brequest (p for power and -b for bandwidth). It is important to notice that the variable -prequest in this case is only available for HOST, and -brequest is only available for LINK. Example: suppose there are -two categories for tasks: request and compute. To create a customized graph -representation with a proportional separation of host and link utilization, use -as configuration for HOST and LINK this: -\verbatim - HOST = { - size = power; - scale = global; - - sep_host = { - type = separation; - size = power; - values = (prequest, pcomputation); - }; - }; - - LINK = { - src = source; - dst = destination; - size = bandwidth; - scale = global; - - sep_link = { - type = separation; - size = bandwidth; - values = (brequest, bcomputation); - }; - }; -\endverbatim -Where sep_host contains a composition of type separation where -its max size is the power of the host and the variables prequest -and pcomputation are drawn proportionally to the size of the HOST. And -sep_link is also a separation where max is defined as the -bandwidth of the link, and the variables brequest and -bcomputation are drawn proportionally within a LINK. -This configuration enables the analysis of resource utilization by MSG tasks, -and the identification of load-balancing issues, network bottlenecks, for -instance. \n -Other compositions: besides separation, it is possible to use -other types of compositions, such as gradients, and colors, like this: -\verbatim - gra_host = { - type = gradient; - scale = global; - values = (numberOfTasks); - }; - color_host = { - type = color; - values = (is_server); - }; -\endverbatim -Where gra_host creates a gradient within a node of the graph, using a -global scale and using as value a variable called numberOfTasks, that -could be declared by the user using the optional tracing functions of SimGrid. -If scale is global, the max and min value for the gradient will be equal to the -max and min numberOfTasks among all hosts, and if scale is local, the max and -min value based on the value of numberOfTasks locally in each host. -And color_host composition draws a square based on a positive value of -the variable is_server, that could also be defined by the user using the -SimGrid tracing functions. \n -The Graph Visualization: The next figure shows a graph visualization of a -given time-slice of the masterslave_forwarder example (present in the SimGrid -sources). The red color indicates tasks from the compute category. This -visualization was generated with the following configuration: -\verbatim -{ - node = (HOST); - edge = (LINK); - - HOST = { - size = power; - scale = global; - - sep_host = { - type = separation; - size = power; - values = (pcompute, pfinalize); - }; - }; - LINK = { - src = source; - dst = destination; - size = bandwidth; - scale = global; - - sep_link = { - type = separation; - size = bandwidth; - values = (bcompute, bfinalize); - }; - }; - graphviz-algorithm = neato; -} -\endverbatim -
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- -- Understading Triva - colors: An important issue when using Triva is how - to define colors. To do that, we have to know which variables are defined in -the trace file generated by the SimGrid library. The parameter --list -lists the variables for a given trace file: -\verbatim -$ Triva -l masterslave_forwarder.trace -iFile -c platform -c HOST -v power -v is_slave -v is_master -v task_creation -v task_computation -v pcompute -v pfinalize -c LINK -v bandwidth -v latency -v bcompute -v bfinalize -c user_type -\endverbatim -We can see that HOST has seven variables (from power to pfinalize) and LINK has -four (from bandwidth to bfinalize). To define a red color for the -pcompute and bcompute (which are defined based on user category -compute), execute: -\verbatim -$ defaults write Triva 'pcompute Color' '1 0 0' -$ defaults write Triva 'bcompute Color' '1 0 0' -\endverbatim -Where the three numbers in each line are the RGB color with values from 0 to 1. - -\subsection faq_modelchecking Model-Checking -\subsubsection faq_modelchecking_howto How to use it -To enable the experimental SimGrid model-checking support the program should -be executed with the command line argument -\verbatim ---cfg=model-check:1 -\endverbatim -Properties are expressed as assertions using the function -\verbatim -void MC_assert(int prop); -\endverbatim - \section faq_troubleshooting Troubleshooting \subsection faq_trouble_lib_compil SimGrid compilation and installation problems @@ -1754,9 +970,7 @@ informative bug repports: 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 */ @@ -1765,7 +979,7 @@ specific at all, but it's full of good advices). ****************************************************************** -\subsection faq_crosscompile Cross-compiling a Windows DLL of SimGrid from linux +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 @@ -1862,5 +1076,3 @@ 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. - -