X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/13fb4af932a02ea0bd4293d1e55ac071de326f80..e94c2a7fc81a82998524aa55db075be69990d4ea:/doc/doxygen/options.doc diff --git a/doc/doxygen/options.doc b/doc/doxygen/options.doc index 4739cf5def..34bec891a3 100644 --- a/doc/doxygen/options.doc +++ b/doc/doxygen/options.doc @@ -1,4 +1,15 @@ -/*! \page options Configure SimGrid +/*! @page options Configure SimGrid + +@htmlonly +
+@endhtmlonly +@htmlinclude graphical-toc.svg +@htmlonly +
+ +@endhtmlonly A number of options can be given at runtime to change the default SimGrid behavior. For a complete list of all configuration options @@ -9,43 +20,43 @@ report so that we can fix it. Note that some of the options presented here may not be available in your simulators, depending on the @ref install_src_config "compile-time options" that you used. -\tableofcontents +@tableofcontents -\section options_using Passing configuration options to the simulators +@section options_using Passing configuration options to the simulators There is several way to pass configuration options to the simulators. -The most common way is to use the \c --cfg command line argument. For -example, to set the item \c Item to the value \c Value, simply -type the following: \verbatim +The most common way is to use the @c --cfg command line argument. For +example, to set the item @c Item to the value @c Value, simply +type the following: @verbatim my_simulator --cfg=Item:Value (other arguments) -\endverbatim +@endverbatim -Several \c `--cfg` command line arguments can naturally be used. If you +Several @c `--cfg` command line arguments can naturally be used. If you need to include spaces in the argument, don't forget to quote the -argument. You can even escape the included quotes (write \' for ' if +argument. You can even escape the included quotes (write @' for ' if you have your argument between '). -Another solution is to use the \c \ tag in the platform file. The +Another solution is to use the @c @ tag in the platform file. The only restriction is that this tag must occure before the first -platform element (be it \c \, \c \, \c \ or whatever). -The \c \ tag takes an \c id attribute, but it is currently +platform element (be it @c @, @c @, @c @ or whatever). +The @c @ tag takes an @c id attribute, but it is currently ignored so you don't really need to pass it. The important par is that -within that tag, you can pass one or several \c \ tags to specify -the configuration to use. For example, setting \c Item to \c Value +within that tag, you can pass one or several @c @ tags to specify +the configuration to use. For example, setting @c Item to @c Value can be done by adding the following to the beginning of your platform file: -\verbatim +@verbatim -\endverbatim +@endverbatim A last solution is to pass your configuration directly using the C interface. If you happen to use the MSG interface, this is very easy -with the MSG_config() function. If you do not use MSG, that's a bit +with the simgrid::s4u::Engine::setConfig() or MSG_config() functions. If you do not use MSG, that's a bit more complex, as you have to mess with the internal configuration set -directly as follows. Check the \ref XBT_config "relevant page" for -details on all the functions you can use in this context, \c +directly as follows. Check the @ref XBT_config "relevant page" for +details on all the functions you can use in this context, @c _sg_cfg_set being the only configuration set currently used in SimGrid. @@ -62,123 +73,125 @@ int main(int argc, char *argv[]) { } @endcode -\section options_index Index of all existing configuration options +@section options_index Index of all existing configuration options -\note +@note The full list can be retrieved by passing "--help" and "--help-cfg" to an executable that uses SimGrid. -- \c clean-atexit: \ref options_generic_clean_atexit - -- \c contexts/factory: \ref options_virt_factory -- \c contexts/guard-size: \ref options_virt_guard_size -- \c contexts/nthreads: \ref options_virt_parallel -- \c contexts/parallel_threshold: \ref options_virt_parallel -- \c contexts/stack-size: \ref options_virt_stacksize -- \c contexts/synchro: \ref options_virt_parallel - -- \c cpu/maxmin-selective-update: \ref options_model_optim -- \c cpu/model: \ref options_model_select -- \c cpu/optim: \ref options_model_optim - -- \c exception/cutpath: \ref options_exception_cutpath - -- \c host/model: \ref options_model_select - -- \c maxmin/precision: \ref options_model_precision -- \c maxmin/concurrency-limit: \ref options_concurrency_limit - -- \c msg/debug-multiple-use: \ref options_msg_debug_multiple_use - -- \c model-check: \ref options_modelchecking -- \c model-check/checkpoint: \ref options_modelchecking_steps -- \c model-check/communications-determinism: \ref options_modelchecking_comm_determinism -- \c model-check/dot-output: \ref options_modelchecking_dot_output -- \c model-check/hash: \ref options_modelchecking_hash -- \c model-check/property: \ref options_modelchecking_liveness -- \c model-check/max-depth: \ref options_modelchecking_max_depth -- \c model-check/record: \ref options_modelchecking_recordreplay -- \c model-check/reduction: \ref options_modelchecking_reduction -- \c model-check/replay: \ref options_modelchecking_recordreplay -- \c model-check/send-determinism: \ref options_modelchecking_comm_determinism -- \c model-check/sparse-checkpoint: \ref options_modelchecking_sparse_checkpoint -- \c model-check/termination: \ref options_modelchecking_termination -- \c model-check/timeout: \ref options_modelchecking_timeout -- \c model-check/visited: \ref options_modelchecking_visited - -- \c network/bandwidth-factor: \ref options_model_network_coefs -- \c network/crosstraffic: \ref options_model_network_crosstraffic -- \c network/latency-factor: \ref options_model_network_coefs -- \c network/maxmin-selective-update: \ref options_model_optim -- \c network/model: \ref options_model_select -- \c network/optim: \ref options_model_optim -- \c network/sender_gap: \ref options_model_network_sendergap -- \c network/TCP-gamma: \ref options_model_network_gamma -- \c network/weight-S: \ref options_model_network_coefs - -- \c ns3/TcpModel: \ref options_pls -- \c path: \ref options_generic_path -- \c plugin: \ref options_generic_plugin - -- \c storage/max_file_descriptors: \ref option_model_storage_maxfd - -- \c surf/precision: \ref options_model_precision - -- \c For collective operations of SMPI, please refer to Section \ref options_index_smpi_coll -- \c smpi/async-small-thresh: \ref options_model_network_asyncsend -- \c smpi/bw-factor: \ref options_model_smpi_bw_factor -- \c smpi/coll-selector: \ref options_model_smpi_collectives -- \c smpi/comp-adjustment-file: \ref options_model_smpi_adj_file -- \c smpi/cpu-threshold: \ref options_smpi_bench -- \c smpi/display-timing: \ref options_smpi_timing -- \c smpi/grow-injected-times: \ref options_model_smpi_test -- \c smpi/host-speed: \ref options_smpi_bench -- \c smpi/IB-penalty-factors: \ref options_model_network_coefs -- \c smpi/iprobe: \ref options_model_smpi_iprobe -- \c smpi/iprobe-cpu-usage: \ref options_model_smpi_iprobe_cpu_usage -- \c smpi/init: \ref options_model_smpi_init -- \c smpi/keep-temps: \ref options_smpi_temps -- \c smpi/lat-factor: \ref options_model_smpi_lat_factor -- \c smpi/ois: \ref options_model_smpi_ois -- \c smpi/or: \ref options_model_smpi_or -- \c smpi/os: \ref options_model_smpi_os -- \c smpi/papi-events: \ref options_smpi_papi_events -- \c smpi/privatization: \ref options_smpi_privatization -- \c smpi/send-is-detached-thresh: \ref options_model_smpi_detached -- \c smpi/shared-malloc: \ref options_model_smpi_shared_malloc -- \c smpi/shared-malloc-hugepage: \ref options_model_smpi_shared_malloc -- \c smpi/simulate-computation: \ref options_smpi_bench -- \c smpi/test: \ref options_model_smpi_test -- \c smpi/wtime: \ref options_model_smpi_wtime - -- \c Tracing configuration options can be found in Section \ref tracing_tracing_options. - -- \c storage/model: \ref options_storage_model -- \c verbose-exit: \ref options_generic_exit - -- \c vm/model: \ref options_vm_model - -\subsection options_index_smpi_coll Index of SMPI collective algorithms options +- @c clean-atexit: @ref options_generic_clean_atexit + +- @c contexts/factory: @ref options_virt_factory +- @c contexts/guard-size: @ref options_virt_guard_size +- @c contexts/nthreads: @ref options_virt_parallel +- @c contexts/parallel-threshold: @ref options_virt_parallel +- @c contexts/stack-size: @ref options_virt_stacksize +- @c contexts/synchro: @ref options_virt_parallel + +- @c cpu/maxmin-selective-update: @ref options_model_optim +- @c cpu/model: @ref options_model_select +- @c cpu/optim: @ref options_model_optim + +- @c exception/cutpath: @ref options_exception_cutpath + +- @c host/model: @ref options_model_select + +- @c maxmin/precision: @ref options_model_precision +- @c maxmin/concurrency-limit: @ref options_concurrency_limit + +- @c msg/debug-multiple-use: @ref options_msg_debug_multiple_use + +- @c model-check: @ref options_modelchecking +- @c model-check/checkpoint: @ref options_modelchecking_steps +- @c model-check/communications-determinism: @ref options_modelchecking_comm_determinism +- @c model-check/dot-output: @ref options_modelchecking_dot_output +- @c model-check/hash: @ref options_modelchecking_hash +- @c model-check/property: @ref options_modelchecking_liveness +- @c model-check/max-depth: @ref options_modelchecking_max_depth +- @c model-check/record: @ref options_modelchecking_recordreplay +- @c model-check/reduction: @ref options_modelchecking_reduction +- @c model-check/replay: @ref options_modelchecking_recordreplay +- @c model-check/send-determinism: @ref options_modelchecking_comm_determinism +- @c model-check/sparse-checkpoint: @ref options_modelchecking_sparse_checkpoint +- @c model-check/termination: @ref options_modelchecking_termination +- @c model-check/timeout: @ref options_modelchecking_timeout +- @c model-check/visited: @ref options_modelchecking_visited + +- @c network/bandwidth-factor: @ref options_model_network_coefs +- @c network/crosstraffic: @ref options_model_network_crosstraffic +- @c network/latency-factor: @ref options_model_network_coefs +- @c network/maxmin-selective-update: @ref options_model_optim +- @c network/model: @ref options_model_select +- @c network/optim: @ref options_model_optim +- @c network/TCP-gamma: @ref options_model_network_gamma +- @c network/weight-S: @ref options_model_network_coefs + +- @c ns3/TcpModel: @ref options_pls +- @c path: @ref options_generic_path +- @c plugin: @ref options_generic_plugin + +- @c simix/breakpoint: @ref options_generic_breakpoint + +- @c storage/max_file_descriptors: @ref option_model_storage_maxfd + +- @c surf/precision: @ref options_model_precision + +- For collective operations of SMPI, please refer to Section @ref options_index_smpi_coll +- @c smpi/async-small-thresh: @ref options_model_network_asyncsend +- @c smpi/bw-factor: @ref options_model_smpi_bw_factor +- @c smpi/coll-selector: @ref options_model_smpi_collectives +- @c smpi/comp-adjustment-file: @ref options_model_smpi_adj_file +- @c smpi/cpu-threshold: @ref options_smpi_bench +- @c smpi/display-timing: @ref options_smpi_timing +- @c smpi/grow-injected-times: @ref options_model_smpi_test +- @c smpi/host-speed: @ref options_smpi_bench +- @c smpi/IB-penalty-factors: @ref options_model_network_coefs +- @c smpi/iprobe: @ref options_model_smpi_iprobe +- @c smpi/iprobe-cpu-usage: @ref options_model_smpi_iprobe_cpu_usage +- @c smpi/init: @ref options_model_smpi_init +- @c smpi/keep-temps: @ref options_smpi_temps +- @c smpi/lat-factor: @ref options_model_smpi_lat_factor +- @c smpi/ois: @ref options_model_smpi_ois +- @c smpi/or: @ref options_model_smpi_or +- @c smpi/os: @ref options_model_smpi_os +- @c smpi/papi-events: @ref options_smpi_papi_events +- @c smpi/privatization: @ref options_smpi_privatization +- @c smpi/privatize-libs: @ref options_smpi_privatize_libs +- @c smpi/send-is-detached-thresh: @ref options_model_smpi_detached +- @c smpi/shared-malloc: @ref options_model_smpi_shared_malloc +- @c smpi/shared-malloc-hugepage: @ref options_model_smpi_shared_malloc +- @c smpi/simulate-computation: @ref options_smpi_bench +- @c smpi/test: @ref options_model_smpi_test +- @c smpi/wtime: @ref options_model_smpi_wtime + +- Tracing configuration options can be found in Section @ref tracing_tracing_options. + +- @c storage/model: @ref options_storage_model +- @c verbose-exit: @ref options_generic_exit + +- @c vm/model: @ref options_vm_model + +@subsection options_index_smpi_coll Index of SMPI collective algorithms options TODO: All available collective algorithms will be made available via the ``smpirun --help-coll`` command. -\section options_model Configuring the platform models +@section options_model Configuring the platform models -\anchor options_storage_model -\anchor options_vm_model -\subsection options_model_select Selecting the platform models +@anchor options_storage_model +@anchor options_vm_model +@subsection options_model_select Selecting the platform models SimGrid comes with several network, CPU and storage models built in, and you can change the used model at runtime by changing the passed configuration. The three main configuration items are given below. -For each of these items, passing the special \c help value gives -you a short description of all possible values. Also, \c --help-models +For each of these items, passing the special @c help value gives +you a short description of all possible values. Also, @c --help-models should provide information about all models for all existing resources. - - \b network/model: specify the used network model - - \b cpu/model: specify the used CPU model - - \b host/model: specify the used host model - - \b storage/model: specify the used storage model (there is currently only one such model - this option is hence only useful for future releases) - - \b vm/model: specify the model for virtual machines (there is currently only one such model - this option is hence only useful for future releases) + - @b network/model: specify the used network model + - @b cpu/model: specify the used CPU model + - @b host/model: specify the used host model + - @b storage/model: specify the used storage model (there is currently only one such model - this option is hence only useful for future releases) + - @b vm/model: specify the model for virtual machines (there is currently only one such model - this option is hence only useful for future releases) As of writing, the following network models are accepted. Over the time new models can be added, and some experimental models can be @@ -189,39 +202,39 @@ Network Model for Simulation of Grid Application while LV08 is described in Accuracy Study and Improvement of Network Simulation in the SimGrid Framework. - - \b LV08 (default one): Realistic network analytic model - (slow-start modeled by multiplying latency by 10.4, bandwidth by - .92; bottleneck sharing uses a payload of S=8775 for evaluating RTT) - - \anchor options_model_select_network_constant \b Constant: Simplistic network model where all communication + - @b LV08 (default one): Realistic network analytic model + (slow-start modeled by multiplying latency by 13.01, bandwidth by + .97; bottleneck sharing uses a payload of S=20537 for evaluating RTT) + - @anchor options_model_select_network_constant @b Constant: Simplistic network model where all communication take a constant time (one second). This model provides the lowest realism, but is (marginally) faster. - - \b SMPI: Realistic network model specifically tailored for HPC + - @b SMPI: Realistic network model specifically tailored for HPC settings (accurate modeling of slow start with correction factors on - three intervals: < 1KiB, < 64 KiB, >= 64 KiB). See also \ref + three intervals: < 1KiB, < 64 KiB, >= 64 KiB). See also @ref options_model_network_coefs "this section" for more info. - - \b IB: Realistic network model specifically tailored for HPC + - @b IB: Realistic network model specifically tailored for HPC settings with InfiniBand networks (accurate modeling contention behavior, based on the model explained in http://mescal.imag.fr/membres/jean-marc.vincent/index.html/PhD/Vienne.pdf). - See also \ref options_model_network_coefs "this section" for more info. - - \b CM02: Legacy network analytic model (Very similar to LV08, but + See also @ref options_model_network_coefs "this section" for more info. + - @b CM02: Legacy network analytic model (Very similar to LV08, but without corrective factors. The timings of small messages are thus poorly modeled) - - \b Reno: Model from Steven H. Low using lagrange_solve instead of + - @b Reno: Model from Steven H. Low using lagrange_solve instead of lmm_solve (experts only; check the code for more info). - - \b Reno2: Model from Steven H. Low using lagrange_solve instead of + - @b Reno2: Model from Steven H. Low using lagrange_solve instead of lmm_solve (experts only; check the code for more info). - - \b Vegas: Model from Steven H. Low using lagrange_solve instead of + - @b Vegas: Model from Steven H. Low using lagrange_solve instead of lmm_solve (experts only; check the code for more info). If you compiled SimGrid accordingly, you can use packet-level network -simulators as network models (see \ref pls_ns3). In that case, you have +simulators as network models (see @ref pls_ns3). In that case, you have two extra models, described below, and some -\ref options_pls "specific additional configuration flags". - - \b NS3: Network pseudo-model using the NS3 tcp model +@ref options_pls "specific additional configuration flags". + - @b NS3: Network pseudo-model using the NS3 tcp model Concerning the CPU, we have only one model for now: - - \b Cas01: Simplistic CPU model (time=size/power) + - @b Cas01: Simplistic CPU model (time=size/power) The host concept is the aggregation of a CPU with a network card. Three models exists, but actually, only 2 of them are @@ -232,75 +245,82 @@ existing CPU model with an existing network model, but does not allow parallel tasks because these beasts need some collaboration between the network and CPU model. That is why, ptask_07 is used by default when using SimDag. - - \b default: Default host model. Currently, CPU:Cas01 and + - @b default: Default host model. Currently, CPU:Cas01 and network:LV08 (with cross traffic enabled) - - \b compound: Host model that is automatically chosen if + - @b compound: Host model that is automatically chosen if you change the network and CPU models - - \b ptask_L07: Host model somehow similar to Cas01+CM02 but + - @b ptask_L07: Host model somehow similar to Cas01+CM02 but allowing "parallel tasks", that are intended to model the moldable tasks of the grid scheduling literature. -\subsection options_generic_plugin Plugins +@subsection options_generic_plugin Plugins -SimGrid supports the use of plugins; currently, no known plugins -can be activated but there are use-cases where you may want to write -your own plugin (for instance, for logging). +SimGrid plugins allow to extend the framework without changing its +source code directly. Read the source code of the existing plugins to +learn how to do so (in ``src/plugins``), and ask your questions to the +usual channels (Stack Overflow, Mailing list, IRC). The basic idea is +that plugins usually register callbacks to some signals of interest. +If they need to store some information about a given object (Link, CPU +or Actor), they do so through the use of a dedicated object extension. -Plugins can for instance define own classes that inherit from -existing classes (for instance, a class "CpuEnergy" inherits from -"Cpu" to assess energy consumption). +Some of the existing plugins can be activated from the command line, +meaning that you can activate them from the command line without any +modification to your simulation code. For example, you can activate +the host energy plugin by adding the following to your command line: -The plugin connects to the code by registering callbacks using -``signal.connect(callback)`` (see file ``src/surf/plugins/energy.cpp`` for -details). +@verbatim + --cfg=plugin:host_energy +@endverbatim -\verbatim - --cfg=plugin:Energy -\endverbatim +Here is the full list of plugins that can be activated this way: -\note - This option is case-sensitive: Energy and energy are not the same! + - @b host_energy: keeps track of the energy dissipated by + computations. More details in @ref plugin_energy. + - @b link_energy: keeps track of the energy dissipated by + communications. More details in @ref SURF_plugin_energy. + - @b host_load: keeps track of the computational load. + More details in @ref plugin_load. -\subsection options_model_optim Optimization level of the platform models +@subsection options_model_optim Optimization level of the platform models The network and CPU models that are based on lmm_solve (that is, all our analytical models) accept specific optimization configurations. - - items \b network/optim and \b cpu/optim (both default to 'Lazy'): - - \b Lazy: Lazy action management (partial invalidation in lmm + + - items @b network/optim and @b cpu/optim (both default to 'Lazy'): + - @b Lazy: Lazy action management (partial invalidation in lmm + heap in action remaining). - - \b TI: Trace integration. Highly optimized mode when using + - @b TI: Trace integration. Highly optimized mode when using availability traces (only available for the Cas01 CPU model for now). - - \b Full: Full update of remaining and variables. Slow but may be + - @b Full: Full update of remaining and variables. Slow but may be useful when debugging. - - items \b network/maxmin-selective-update and - \b cpu/maxmin-selective-update: configure whether the underlying + - items @b network/maxmin-selective-update and + @b cpu/maxmin-selective-update: configure whether the underlying should be lazily updated or not. It should have no impact on the computed timings, but should speed up the computation. -It is still possible to disable the \c maxmin-selective-update feature +It is still possible to disable the @c maxmin-selective-update feature because it can reveal counter-productive in very specific scenarios where the interaction level is high. In particular, if all your communication share a given backbone link, you should disable it: -without \c maxmin-selective-update, every communications are updated +without @c maxmin-selective-update, every communications are updated at each step through a simple loop over them. With that feature enabled, every communications will still get updated in this case (because of the dependency induced by the backbone), but through a complicated pattern aiming at following the actual dependencies. -\subsection options_model_precision Numerical precision of the platform models +@subsection options_model_precision Numerical precision of the platform models The analytical models handle a lot of floating point values. It is possible to change the epsilon used to update and compare them through -the \b maxmin/precision item (default value: 0.00001). Changing it +the @b maxmin/precision item (default value: 0.00001). Changing it may speedup the simulation by discarding very small actions, at the price of a reduced numerical precision. -\subsection options_concurrency_limit Concurrency limit +@subsection options_concurrency_limit Concurrency limit The maximum number of variables per resource can be tuned through -the \b maxmin/concurrency-limit item. The default value is -1, meaning that +the @b maxmin/concurrency-limit item. The default value is -1, meaning that there is no such limitation. You can have as many simultaneous actions per resources as you want. If your simulation presents a very high level of concurrency, it may help to use e.g. 100 as a value here. It means that at @@ -312,22 +332,22 @@ Such limitations help both to the simulation speed and simulation accuracy on highly constrained scenarios, but the simulation speed suffers of this setting on regular (less constrained) scenarios so it is off by default. -\subsection options_model_network Configuring the Network model +@subsection options_model_network Configuring the Network model -\subsubsection options_model_network_gamma Maximal TCP window size +@subsubsection options_model_network_gamma Maximal TCP window size The analytical models need to know the maximal TCP window size to take -the TCP congestion mechanism into account. This is set to 20000 by -default, but can be changed using the \b network/TCP-gamma item. +the TCP congestion mechanism into account. This is set to 4194304 by +default, but can be changed using the @b network/TCP-gamma item. On linux, this value can be retrieved using the following commands. Both give a set of values, and you should use the last one, -which is the maximal size.\verbatim +which is the maximal size.@verbatim cat /proc/sys/net/ipv4/tcp_rmem # gives the sender window cat /proc/sys/net/ipv4/tcp_wmem # gives the receiver window -\endverbatim +@endverbatim -\subsubsection options_model_network_coefs Correcting important network parameters +@subsubsection options_model_network_coefs Correcting important network parameters SimGrid can take network irregularities such as a slow startup or changing behavior depending on the message size into account. @@ -348,14 +368,14 @@ InfiniBand network behavior can be modeled through 3 parameters, as explained in this PhD thesis. These factors can be changed through the following option: -\verbatim +@verbatim smpi/IB-penalty-factors:"βe;βs;γs" -\endverbatim +@endverbatim By default SMPI uses factors computed on the Stampede Supercomputer at TACC, with optimal deployment of processes on nodes. -\subsubsection options_model_network_crosstraffic Simulating cross-traffic +@subsubsection options_model_network_crosstraffic Simulating cross-traffic As of SimGrid v3.7, cross-traffic effects can be taken into account in analytical simulations. It means that ongoing and incoming @@ -368,37 +388,28 @@ For that to work, your platform must have two links for each pair of interconnected hosts. An example of usable platform is available in examples/platforms/crosstraffic.xml. -This is activated through the \b network/crosstraffic item, that +This is activated through the @b network/crosstraffic item, that can be set to 0 (disable this feature) or 1 (enable it). Note that with the default host model this option is activated by default. -\subsubsection options_model_network_sendergap Simulating sender gap - -(this configuration item is experimental and may change or disapear) - -It is possible to specify a timing gap between consecutive emission on -the same network card through the \b network/sender-gap item. This -is still under investigation as of writting, and the default value is -to wait 10 microseconds (1e-5 seconds) between emissions. - -\subsubsection options_model_network_asyncsend Simulating asyncronous send +@subsubsection options_model_network_asyncsend Simulating asyncronous send (this configuration item is experimental and may change or disapear) It is possible to specify that messages below a certain size will be sent as soon as the call to MPI_Send is issued, without waiting for the correspondant receive. This threshold can be configured through the -\b smpi/async-small-thresh item. The default value is 0. This behavior can also be +@b smpi/async-small-thresh item. The default value is 0. This behavior can also be manually set for MSG mailboxes, by setting the receiving mode of the mailbox -with a call to \ref MSG_mailbox_set_async . For MSG, all messages sent to this +with a call to @ref MSG_mailbox_set_async . For MSG, all messages sent to this mailbox will have this behavior, so consider using two mailboxes if needed. This value needs to be smaller than or equals to the threshold set at -\ref options_model_smpi_detached , because asynchronous messages are +@ref options_model_smpi_detached , because asynchronous messages are meant to be detached as well. -\subsubsection options_pls Configuring packet-level pseudo-models +@subsubsection options_pls Configuring packet-level pseudo-models When using the packet-level pseudo-models, several specific configuration flags are provided to configure the associated tools. @@ -407,45 +418,45 @@ of the associated tools, since we only added the items that we needed ourselves. Feel free to request more items (or even better: provide patches adding more items). -When using NS3, the only existing item is \b ns3/TcpModel, +When using NS3, the only existing item is @b ns3/TcpModel, corresponding to the ns3::TcpL4Protocol::SocketType configuration item in NS3. The only valid values (enforced on the SimGrid side) are 'NewReno' or 'Reno' or 'Tahoe'. -\subsection options_model_storage Configuring the Storage model +@subsection options_model_storage Configuring the Storage model -\subsubsection option_model_storage_maxfd Maximum amount of file descriptors per host +@subsubsection option_model_storage_maxfd Maximum amount of file descriptors per host Each host maintains a fixed-size array of its file descriptors. You -can change its size (1024 by default) through the \b +can change its size (1024 by default) through the @b storage/max_file_descriptors item to either enlarge it if your application requires it or to reduce it to save memory space. -\section options_modelchecking Configuring the Model-Checking +@section options_modelchecking Configuring the Model-Checking To enable the SimGrid model-checking support the program should be executed using the simgrid-mc wrapper: -\verbatim +@verbatim simgrid-mc ./my_program -\endverbatim +@endverbatim Safety properties are expressed as assertions using the function -\verbatim +@verbatim void MC_assert(int prop); -\endverbatim +@endverbatim -\subsection options_modelchecking_liveness Specifying a liveness property +@subsection options_modelchecking_liveness Specifying a liveness property If you want to specify liveness properties (beware, that's experimental), you have to pass them on the command line, specifying the name of the file containing the property, as formatted by the ltl2ba program. -\verbatim +@verbatim --cfg=model-check/property: -\endverbatim +@endverbatim -\subsection options_modelchecking_steps Going for stateful verification +@subsection options_modelchecking_steps Going for stateful verification By default, the system is backtracked to its initial state to explore another path instead of backtracking to the exact step before the fork @@ -458,11 +469,11 @@ Beware, this will certainly explode your memory. Larger values are probably better, make sure to experiment a bit to find the right setting for your specific system. -\verbatim +@verbatim --cfg=model-check/checkpoint:1 -\endverbatim +@endverbatim -\subsection options_modelchecking_reduction Specifying the kind of reduction +@subsection options_modelchecking_reduction Specifying the kind of reduction The main issue when using the model-checking is the state space explosion. To counter that problem, several exploration reduction @@ -472,9 +483,9 @@ properties. In particular, the DPOR method cannot be applied on liveness properties since it may break some cycles in the exploration that are important to the property validity. -\verbatim +@verbatim --cfg=model-check/reduction: -\endverbatim +@endverbatim For now, this configuration variable can take 2 values: * none: Do not apply any kind of reduction (mandatory for now for @@ -482,22 +493,24 @@ For now, this configuration variable can take 2 values: * dpor: Apply Dynamic Partial Ordering Reduction. Only valid if you verify local safety properties (default value for safety checks). -\subsection options_modelchecking_visited model-check/visited, Cycle detection +@subsection options_modelchecking_visited model-check/visited, Cycle detection In order to detect cycles, the model-checker needs to check if a new explored -state is in fact the same state than a previous one. In order to do this, +state is in fact the same state than a previous one. For that, the model-checker can take a snapshot of each visited state: this snapshot is then used to compare it with subsequent states in the exploration graph. -The \b model-check/visited is the maximum number of states which are stored in -memory. If the maximum number of snapshotted state is reached some states will -be removed from the memory and some cycles might be missed. +The @b model-check/visited option is the maximum number of states which are stored in +memory. If the maximum number of snapshotted state is reached, some states will +be removed from the memory and some cycles might be missed. Small +values can lead to incorrect verifications, but large value can +exhaust your memory, so choose carefully. By default, no state is snapshotted and cycles cannot be detected. -\subsection options_modelchecking_termination model-check/termination, Non termination detection +@subsection options_modelchecking_termination model-check/termination, Non termination detection -The \b model-check/termination configuration item can be used to report if a +The @b model-check/termination configuration item can be used to report if a non-termination execution path has been found. This is a path with a cycle which means that the program might never terminate. @@ -505,44 +518,44 @@ This only works in safety mode. This options is disabled by default. -\subsection options_modelchecking_dot_output model-check/dot-output, Dot output +@subsection options_modelchecking_dot_output model-check/dot-output, Dot output -If set, the \b model-check/dot-output configuration item is the name of a file +If set, the @b model-check/dot-output configuration item is the name of a file in which to write a dot file of the path leading the found property (safety or liveness violation) as well as the cycle for liveness properties. This dot file can then fed to the graphviz dot tool to generate an corresponding graphical representation. -\subsection options_modelchecking_max_depth model-check/max_depth, Depth limit +@subsection options_modelchecking_max_depth model-check/max-depth, Depth limit -The \b model-checker/max-depth can set the maximum depth of the exploration +The @b model-checker/max-depth can set the maximum depth of the exploration graph of the model-checker. If this limit is reached, a logging message is sent and the results might not be exact. By default, there is not depth limit. -\subsection options_modelchecking_timeout Handling of timeout +@subsection options_modelchecking_timeout Handling of timeout By default, the model-checker does not handle timeout conditions: the `wait` -operations never time out. With the \b model-check/timeout configuration item -set to \b yes, the model-checker will explore timeouts of `wait` operations. +operations never time out. With the @b model-check/timeout configuration item +set to @b yes, the model-checker will explore timeouts of `wait` operations. -\subsection options_modelchecking_comm_determinism Communication determinism +@subsection options_modelchecking_comm_determinism Communication determinism -The \b model-check/communications-determinism and -\b model-check/send-determinism items can be used to select the communication +The @b model-check/communications-determinism and +@b model-check/send-determinism items can be used to select the communication determinism mode of the model-checker which checks determinism properties of the communications of an application. -\subsection options_modelchecking_sparse_checkpoint Per page checkpoints +@subsection options_modelchecking_sparse_checkpoint Per page checkpoints When the model-checker is configured to take a snapshot of each explored state -(with the \b model-checker/visited item), the memory consumption can rapidly +(with the @b model-checker/visited item), the memory consumption can rapidly reach GiB ou Tib of memory. However, for many workloads, the memory does not change much between different snapshots and taking a complete copy of each snapshot is a waste of memory. -The \b model-check/sparse-checkpoint option item can be set to \b yes in order +The @b model-check/sparse-checkpoint option item can be set to @b yes in order to avoid making a complete copy of each snapshot: instead, each snapshot will be decomposed in blocks which will be stored separately. If multiple snapshots share the same block (or if the same block @@ -559,28 +572,28 @@ snapshotting strategy. This option is currently disabled by default. -\subsection options_mc_perf Performance considerations for the model checker +@subsection options_mc_perf Performance considerations for the model checker The size of the stacks can have a huge impact on the memory consumption when using model-checking. By default, each snapshot will save a copy of the whole stacks and not only of the part which is really meaningful: you should expect the contribution of the memory -consumption of the snapshots to be \f$ \mbox{number of processes} -\times \mbox{stack size} \times \mbox{number of states} \f$. +consumption of the snapshots to be @f$ @mbox{number of processes} +@times @mbox{stack size} @times @mbox{number of states} @f$. -The \b model-check/sparse-checkpoint can be used to reduce the memory +The @b model-check/sparse-checkpoint can be used to reduce the memory consumption by trying to share memory between the different snapshots. When compiled against the model checker, the stacks are not protected with guards: if the stack size is too small for your application, the stack will silently overflow on other parts of the -memory (see \ref options_virt_guard_size). +memory (see @ref options_virt_guard_size). -\subsection options_modelchecking_hash Hashing of the state (experimental) +@subsection options_modelchecking_hash Hashing of the state (experimental) Usually most of the time of the model-checker is spent comparing states. This process is complicated and consumes a lot of bandwidth and cache. -In order to speedup the state comparison, the experimental \b model-checker/hash +In order to speedup the state comparison, the experimental @b model-checker/hash configuration item enables the computation of a hash summarizing as much information of the state as possible into a single value. This hash can be used to avoid most of the comparisons: the costly comparison is then only used when @@ -590,7 +603,7 @@ Currently most of the state is not included in the hash because the implementation was found to be buggy and this options is not as useful as it could be. For this reason, it is currently disabled by default. -\subsection options_modelchecking_recordreplay Record/replay (experimental) +@subsection options_modelchecking_recordreplay Record/replay (experimental) As the model-checker keeps jumping at different places in the execution graph, it is difficult to understand what happens when trying to debug an application @@ -606,7 +619,7 @@ the model-checker and replay it without the model-checker. When the model-checker finds an interesting path in the application execution graph (where a safety or liveness property is violated), it can generate an identifier for this path. In order to enable this behavious the -\b model-check/record must be set to \b yes. By default, this behaviour is not +@b model-check/record must be set to @b yes. By default, this behaviour is not enabled. This is an example of output: @@ -626,7 +639,7 @@ This is an example of output: This path can then be replayed outside of the model-checker (and even in -non-MC build of simgrid) by setting the \b model-check/replay item to the given +non-MC build of simgrid) by setting the @b model-check/replay item to the given path. The other options should be the same (but the model-checker should be disabled). @@ -634,9 +647,9 @@ The format and meaning of the path may change between different releases so the same release of Simgrid should be used for the record phase and the replay phase. -\section options_virt Configuring the User Process Virtualization +@section options_virt Configuring the User Process Virtualization -\subsection options_virt_factory Selecting the virtualization factory +@subsection options_virt_factory Selecting the virtualization factory In SimGrid, the user code is virtualized in a specific mechanism that allows the simulation kernel to control its execution: when a user @@ -647,27 +660,27 @@ graphically in the [relevant tutorial, available online](http://simgrid.gforge.i In SimGrid, the containers in which user processes are virtualized are called contexts. Several context factory are provided, and you can -select the one you want to use with the \b contexts/factory +select the one you want to use with the @b contexts/factory configuration item. Some of the following may not exist on your machine because of portability issues. In any case, the default one should be the most effcient one (please report bugs if the auto-detection fails for you). They are approximately sorted here from the slowest to the most efficient: - - \b thread: very slow factory using full featured threads (either + - @b thread: very slow factory using full featured threads (either pthreads or windows native threads). They are slow but very standard. Some debuggers or profilers only work with this factory. - - \b java: Java applications are virtualized onto java threads (that + - @b java: Java applications are virtualized onto java threads (that are regular pthreads registered to the JVM) - - \b ucontext: fast factory using System V contexts (Linux and FreeBSD only) - - \b boost: This uses the [context implementation](http://www.boost.org/doc/libs/1_59_0/libs/context/doc/html/index.html) + - @b ucontext: fast factory using System V contexts (Linux and FreeBSD only) + - @b boost: This uses the [context implementation](http://www.boost.org/doc/libs/1_59_0/libs/context/doc/html/index.html) of the boost library for a performance that is comparable to our - raw implementation.\nInstall the relevant library (e.g. with the + raw implementation.@n Install the relevant library (e.g. with the libboost-contexts-dev package on Debian/Ubuntu) and recompile SimGrid. Note that our implementation is not compatible with recent implementations of the library, and it will be hard to fix this since the library's author decided to hide an API that we were using. - - \b raw: amazingly fast factory using a context switching mechanism + - @b raw: amazingly fast factory using a context switching mechanism of our own, directly implemented in assembly (only available for x86 and amd64 platforms for now) and without any unneeded system call. @@ -679,7 +692,7 @@ to debug concurrency issues. Valgrind is also more comfortable with threads, but it should be usable with all factories (but the callgrind tool that really don't like raw and ucontext factories). -\subsection options_virt_stacksize Adapting the used stack size +@subsection options_virt_stacksize Adapting the used stack size Each virtualized used process is executed using a specific system stack. The size of this stack has a huge impact on the simulation @@ -689,7 +702,7 @@ rather disturbing: this leads to stack overflow (overwriting other stacks), leading to segfaults with corrupted stack traces. If you want to push the scalability limits of your code, you might -want to reduce the \b contexts/stack-size item. Its default value +want to reduce the @b contexts/stack-size item. Its default value is 8192 (in KiB), while our Chord simulation works with stacks as small as 16 KiB, for example. For the thread factory, the default value is the one of the system but you can still change it with this parameter. @@ -697,16 +710,16 @@ is the one of the system but you can still change it with this parameter. The operating system should only allocate memory for the pages of the stack which are actually used and you might not need to use this in most cases. However, this setting is very important when using the -model checker (see \ref options_mc_perf). +model checker (see @ref options_mc_perf). -\subsection options_virt_guard_size Disabling stack guard pages +@subsection options_virt_guard_size Disabling stack guard pages A stack guard page is usually used which prevents the stack of a given actor from overflowing on another stack. But the performance impact may become prohibitive when the amount of actors increases. The -option \b contexts:guard-size is the number of stack guard pages used. +option @b contexts:guard-size is the number of stack guard pages used. By setting it to 0, no guard pages will be used: in this case, you -should avoid using small stacks (\b stack-size) as the stack will +should avoid using small stacks (@b stack-size) as the stack will silently overflow on other parts of the memory. When no stack guard page is created, stacks may then silently overflow @@ -715,26 +728,26 @@ application. This happens: - on Windows systems; - when the model checker is enabled; -- and of course when guard pages are explicitely disabled (with \b contexts:guard-size=0). +- and of course when guard pages are explicitely disabled (with @b contexts:guard-size=0). -\subsection options_virt_parallel Running user code in parallel +@subsection options_virt_parallel Running user code in parallel Parallel execution of the user code is only considered stable in SimGrid v3.7 and higher, and mostly for MSG simulations. SMPI simulations may well fail in parallel mode. It is described in INRIA RR-7653. -If you are using the \c ucontext or \c raw context factories, you can +If you are using the @c ucontext or @c raw context factories, you can request to execute the user code in parallel. Several threads are launched, each of them handling as much user contexts at each run. To -actiave this, set the \b contexts/nthreads item to the amount of +actiave this, set the @b contexts/nthreads item to the amount of cores that you have in your computer (or lower than 1 to have the amount of cores auto-detected). Even if you asked several worker threads using the previous option, you can request to start the parallel execution (and pay the associated synchronization costs) only if the potential parallelism is -large enough. For that, set the \b contexts/parallel-threshold +large enough. For that, set the @b contexts/parallel-threshold item to the minimal amount of user contexts needed to start the parallel execution. In any given simulation round, if that amount is not reached, the contexts will be run sequentially directly by the @@ -743,24 +756,24 @@ option is mainly useful when the grain of the user code is very fine, because our synchronization is now very efficient. When parallel execution is activated, you can choose the -synchronization schema used with the \b contexts/synchro item, +synchronization schema used with the @b contexts/synchro item, which value is either: - - \b futex: ultra optimized synchronisation schema, based on futexes + - @b futex: ultra optimized synchronisation schema, based on futexes (fast user-mode mutexes), and thus only available on Linux systems. This is the default mode when available. - - \b posix: slow but portable synchronisation using only POSIX + - @b posix: slow but portable synchronisation using only POSIX primitives. - - \b busy_wait: not really a synchronisation: the worker threads + - @b busy_wait: not really a synchronisation: the worker threads constantly request new contexts to execute. It should be the most efficient synchronisation schema, but it loads all the cores of your machine for no good reason. You probably prefer the other less eager schemas. -\section options_tracing Configuring the tracing subsystem +@section options_tracing Configuring the tracing subsystem -The \ref outcomes_vizu "tracing subsystem" can be configured in several +The @ref outcomes_vizu "tracing subsystem" can be configured in several different ways depending on the nature of the simulator (MSG, SimDag, -SMPI) and the kind of traces that need to be obtained. See the \ref +SMPI) and the kind of traces that need to be obtained. See the @ref tracing_tracing_options "Tracing Configuration Options subsection" to get a detailed description of each configuration option. @@ -769,27 +782,27 @@ you never used the tracing API. - Any SimGrid-based simulator (MSG, SimDag, SMPI, ...) and raw traces: -\verbatim +@verbatim --cfg=tracing:yes --cfg=tracing/uncategorized:yes --cfg=triva/uncategorized:uncat.plist -\endverbatim +@endverbatim The first parameter activates the tracing subsystem, the second tells it to trace host and link utilization (without any categorization) and the third creates a graph configuration file to configure Triva when analysing the resulting trace file. - MSG or SimDag-based simulator and categorized traces (you need to declare categories and classify your tasks according to them) -\verbatim +@verbatim --cfg=tracing:yes --cfg=tracing/categorized:yes --cfg=triva/categorized:cat.plist -\endverbatim +@endverbatim The first parameter activates the tracing subsystem, the second tells it to trace host and link categorized utilization and the third creates a graph configuration file to configure Triva when analysing the resulting trace file. - SMPI simulator and traces for a space/time view: -\verbatim +@verbatim smpirun -trace ... -\endverbatim +@endverbatim The -trace parameter for the smpirun script runs the simulation with --cfg=tracing:yes and --cfg=tracing/smpi:yes. Check the smpirun's -help parameter for additional tracing options. @@ -799,22 +812,22 @@ correctly identify them later, or to provide data that can be used to reproduce an experiment. You have two ways to do that: - Add a string on top of the trace file as comment: -\verbatim +@verbatim --cfg=tracing/comment:my_simulation_identifier -\endverbatim +@endverbatim - Add the contents of a textual file on top of the trace file as comment: -\verbatim +@verbatim --cfg=tracing/comment-file:my_file_with_additional_information.txt -\endverbatim +@endverbatim Please, use these two parameters (for comments) to make reproducible simulations. For additional details about this and all tracing -options, check See the \ref tracing_tracing_options. +options, check See the @ref tracing_tracing_options. -\section options_msg Configuring MSG +@section options_msg Configuring MSG -\subsection options_msg_debug_multiple_use Debugging MSG +@subsection options_msg_debug_multiple_use Debugging MSG Sometimes your application may try to send a task that is still being executed somewhere else, making it impossible to send this task. However, @@ -823,40 +836,40 @@ doing. This option shows a backtrace of the other process. Enable this option by adding -\verbatim +@verbatim --cfg=msg/debug-multiple-use:on -\endverbatim +@endverbatim -\section options_smpi Configuring SMPI +@section options_smpi Configuring SMPI The SMPI interface provides several specific configuration items. These are uneasy to see since the code is usually launched through the -\c smiprun script directly. +@c smiprun script directly. -\subsection options_smpi_bench smpi/bench: Automatic benchmarking of SMPI code +@subsection options_smpi_bench smpi/bench: Automatic benchmarking of SMPI code In SMPI, the sequential code is automatically benchmarked, and these computations are automatically reported to the simulator. That is to -say that if you have a large computation between a \c MPI_Recv() and a -\c MPI_Send(), SMPI will automatically benchmark the duration of this +say that if you have a large computation between a @c MPI_Recv() and a +@c MPI_Send(), SMPI will automatically benchmark the duration of this code, and create an execution task within the simulator to take this into account. For that, the actual duration is measured on the host machine and then scaled to the power of the corresponding simulated -machine. The variable \b smpi/host-speed allows to specify the +machine. The variable @b smpi/host-speed allows to specify the computational speed of the host machine (in flop/s) to use when scaling the execution times. It defaults to 20000, but you really want to update it to get accurate simulation results. When the code is constituted of numerous consecutive MPI calls, the previous mechanism feeds the simulation kernel with numerous tiny -computations. The \b smpi/cpu-threshold item becomes handy when this +computations. The @b smpi/cpu-threshold item becomes handy when this impacts badly the simulation performance. It specifies a threshold (in seconds) below which the execution chunks are not reported to the simulation kernel (default value: 1e-6). -\note +@note The option smpi/cpu-threshold ignores any computation time spent - below this threshold. SMPI does not consider the \a amount of these + below this threshold. SMPI does not consider the @a amount of these computations; there is no offset for this. Hence, by using a value that is too low, you may end up with unreliable simulation results. @@ -873,13 +886,13 @@ being replayed/simulated. At the moment, these computation events can be simulated using SMPI by calling internal smpi_execute*() functions. To disable the benchmarking/simulation of computation in the simulated -application, the variable \b smpi/simulate-computation should be set to no. +application, the variable @b smpi/simulate-computation should be set to no. -\note +@note This option just ignores the timings in your simulation; it still executes the computations itself. If you want to stop SMPI from doing that, you should check the SMPI_SAMPLE macros, documented in the section - \ref SMPI_adapting_speed. + @ref SMPI_adapting_speed. Solution | Computations actually executed? | Computations simulated ? ---------------------------------- | ------------------------------- | ------------------------ @@ -887,17 +900,17 @@ Solution | Computations actually executed? | Computati --cfg=smpi/cpu-threshold:42 | Yes, in all cases | Only if it lasts more than 42 seconds SMPI_SAMPLE() macro | Only once per loop nest (see @ref SMPI_adapting_speed "documentation") | Always -\subsection options_model_smpi_adj_file smpi/comp-adjustment-file: Slow-down or speed-up parts of your code. +@subsection options_model_smpi_adj_file smpi/comp-adjustment-file: Slow-down or speed-up parts of your code. This option allows you to pass a file that contains two columns: The first column defines the section that will be subject to a speedup; the second column is the speedup. For instance: -\verbatim +@verbatim "start:stop","ratio" "exchange_1.f:30:exchange_1.f:130",1.18244559422142 -\endverbatim +@endverbatim The first line is the header - you must include it. The following line means that the code between two consecutive MPI calls on @@ -909,12 +922,12 @@ equal to 1. Of course, you can set any arbitrary filenames you want (so the start and end don't have to be in the same file), but be aware that this mechanism only supports @em consecutive calls! -\note - Please note that you must pass the \b -trace-call-location flag to smpicc +@note + Please note that you must pass the @b -trace-call-location flag to smpicc or smpiff, respectively! This flag activates some macro definitions in our mpi.h / mpi.f files that help with obtaining the call location. -\subsection options_model_smpi_bw_factor smpi/bw-factor: Bandwidth factors +@subsection options_model_smpi_bw_factor smpi/bw-factor: Bandwidth factors The possible throughput of network links is often dependent on the message sizes, as protocols may adapt to different message sizes. With @@ -922,36 +935,36 @@ this option, a series of message sizes and factors are given, helping the simulation to be more realistic. For instance, the current default value is -\verbatim +@verbatim 65472:0.940694;15424:0.697866;9376:0.58729;5776:1.08739;3484:0.77493;1426:0.608902;732:0.341987;257:0.338112;0:0.812084 -\endverbatim +@endverbatim So, messages with size 65472 and more will get a total of MAX_BANDWIDTH*0.940694, messages of size 15424 to 65471 will get MAX_BANDWIDTH*0.697866 and so on. Here, MAX_BANDWIDTH denotes the bandwidth of the link. -\note +@note The SimGrid-Team has developed a script to help you determine these values. You can find more information and the download here: 1. http://simgrid.gforge.inria.fr/contrib/smpi-calibration-doc.html 2. http://simgrid.gforge.inria.fr/contrib/smpi-saturation-doc.html -\subsection options_smpi_timing smpi/display-timing: Reporting simulation time +@subsection options_smpi_timing smpi/display-timing: Reporting simulation time -\b Default: 0 (false) +@b Default: 0 (false) Most of the time, you run MPI code with SMPI to compute the time it would take to run it on a platform. But since the -code is run through the \c smpirun script, you don't have any control +code is run through the @c smpirun script, you don't have any control on the launcher code, making it difficult to report the simulated time -when the simulation ends. If you set the \b smpi/display-timing item -to 1, \c smpirun will display this information when the simulation ends. \verbatim +when the simulation ends. If you set the @b smpi/display-timing item +to 1, @c smpirun will display this information when the simulation ends. @verbatim Simulation time: 1e3 seconds. -\endverbatim +@endverbatim -\subsection options_smpi_temps smpi/keep-temps: not cleaning up after simulation +@subsection options_smpi_temps smpi/keep-temps: not cleaning up after simulation -\b Default: 0 (false) +@b Default: 0 (false) Under some conditions, SMPI generates a lot of temporary files. They usually get cleaned, but you may use this option to not erase these @@ -959,30 +972,30 @@ files. This is for example useful when debugging or profiling executions using the dlopen privatization schema, as missing binary files tend to fool the debuggers. -\subsection options_model_smpi_lat_factor smpi/lat-factor: Latency factors +@subsection options_model_smpi_lat_factor smpi/lat-factor: Latency factors The motivation and syntax for this option is identical to the motivation/syntax -of smpi/bw-factor, see \ref options_model_smpi_bw_factor for details. +of smpi/bw-factor, see @ref options_model_smpi_bw_factor for details. -There is an important difference, though: While smpi/bw-factor \a reduces the +There is an important difference, though: While smpi/bw-factor @a reduces the actual bandwidth (i.e., values between 0 and 1 are valid), latency factors increase the latency, i.e., values larger than or equal to 1 are valid here. This is the default value: -\verbatim +@verbatim 65472:11.6436;15424:3.48845;9376:2.59299;5776:2.18796;3484:1.88101;1426:1.61075;732:1.9503;257:1.95341;0:2.01467 -\endverbatim +@endverbatim -\note +@note The SimGrid-Team has developed a script to help you determine these values. You can find more information and the download here: 1. http://simgrid.gforge.inria.fr/contrib/smpi-calibration-doc.html 2. http://simgrid.gforge.inria.fr/contrib/smpi-saturation-doc.html -\subsection options_smpi_papi_events smpi/papi-events: Trace hardware counters with PAPI +@subsection options_smpi_papi_events smpi/papi-events: Trace hardware counters with PAPI -\warning +@warning This option is experimental and will be subject to change. This feature currently requires superuser privileges, as registers are queried. Only use this feature with code you trust! Call smpirun for instance via @@ -990,96 +1003,86 @@ This is the default value: or run sudo sh -c "echo 0 > /proc/sys/kernel/perf_event_paranoid" In the later case, sudo will not be required. -\note +@note This option is only available when SimGrid was compiled with PAPI support. This option takes the names of PAPI counters and adds their respective values -to the trace files. (See Section \ref tracing_tracing_options.) +to the trace files. (See Section @ref tracing_tracing_options.) It is planned to make this feature available on a per-process (or per-thread?) basis. The first draft, however, just implements a "global" (i.e., for all processes) set of counters, the "default" set. -\verbatim +@verbatim --cfg=smpi/papi-events:"default:PAPI_L3_LDM:PAPI_L2_LDM" -\endverbatim - -\subsection options_smpi_privatization smpi/privatization: Automatic privatization of global variables - -MPI executables are usually meant to be executed in separated processes, but SMPI is -executed in only one process. Global variables from executables will be placed -in the same memory zone and shared between processes, causing intricate bugs. -Several options are possible to avoid this, as described in the main -SMPI publication. -SimGrid provides two ways of automatically privatizing the globals, -and this option allows to choose between them. - - - no (default): Do not automatically privatize variables. - - mmap or yes: Runtime automatic switching of the data segments.\n - SMPI stores a copy of each global data segment for each process, - and at each context switch replaces the actual data with its copy - from the right process. No copy actually occures as this mechanism - uses mmap for efficiency. As such, it is for now limited to - systems supporting this functionnality (all Linux and most BSD).\n - Another limitation is that SMPI only accounts for global variables - defined in the executable. If the processes use external global - variables from dynamic libraries, they won't be switched - correctly. The easiest way to solve this is to statically link - against the library with these globals (but you should never - statically link against the simgrid library itself). - - dlopen: Link multiple times against the binary.\n - SMPI loads several copy of the same binary in memory, resulting in - the natural duplication global variables. Since the dynamic linker - refuses to link the same file several times, the binary is copied - in a temporary file before being dl-loaded (it is erased right - after loading).\n - Note that this feature is somewhat experimental at time of writing - (v3.16) but seems to work.\n - This approach greatly speeds up the context switching, down to - about 40 CPU cycles with our raw contextes, instead of requesting - several syscalls with the \c mmap approach. Another advantage is - that it permits to run the SMPI contexts in parallel, which is - obviously not possible with the \c mmap approach.\n - Further work may be possible to alleviate the memory and disk - overconsumption. It seems that we could - punch holes - in the files before dl-loading them to remove the code and - constants, and mmap these area onto a unique copy. This require - to understand the ELF layout of the file, but would - reduce the disk- and memory- usage to the bare minimum. In - addition, this would reduce the pressure on the CPU caches (in - particular on instruction one). - -\warning +@endverbatim + +@subsection options_smpi_privatization smpi/privatization: Automatic privatization of global variables + +MPI executables are usually meant to be executed in separated +processes, but SMPI is executed in only one process. Global variables +from executables will be placed in the same memory zone and shared +between processes, causing intricate bugs. Several options are +possible to avoid this, as described in the main +SMPI publication and in +the @ref SMPI_what_globals "SMPI documentation". SimGrid provides two +ways of automatically privatizing the globals, and this option allows +to choose between them. + + - no (default when not using smpirun): Do not automatically privatize variables. + Pass @c -no-privatize to smpirun to disable this feature. + - dlopen or yes (default when using smpirun): Link multiple times against the binary. + - mmap (slower, but maybe somewhat more stable): + Runtime automatic switching of the data segments. + +@warning This configuration option cannot be set in your platform file. You can only pass it as an argument to smpirun. + +@subsection options_smpi_privatize_libs smpi/privatize-libs: Automatic privatization of + global variables inside external libraries + +Linux/BSD only: When using dlopen (default) privatization, privatize specific +shared libraries with internal global variables, if they can't be linked statically. +For example libgfortran is usually used for Fortran I/O and indexes in files +can be mixed up. + +@warning + This configuration option can only use either full paths to libraries, or full names. + Check with ldd the name of the library you want to use. + Example: + ldd allpairf90 + libgfortran.so.3 => /usr/lib/x86_64-linux-gnu/libgfortran.so.3 (0x00007fbb4d91b000) + Then you can use --cfg=smpi/privatize-libs:"libgfortran.so.3" or --cfg=smpi/privatize-libs:"/usr/lib/x86_64-linux-gnu/libgfortran.so.3", but not "libgfortran" or "libgfortran.so". + Multiple libraries can be given, semicolon separated. -\subsection options_model_smpi_detached Simulating MPI detached send + +@subsection options_model_smpi_detached Simulating MPI detached send This threshold specifies the size in bytes under which the send will return -immediately. This is different from the threshold detailed in \ref options_model_network_asyncsend +immediately. This is different from the threshold detailed in @ref options_model_network_asyncsend because the message is not effectively sent when the send is posted. SMPI still waits for the correspondant receive to be posted to perform the communication operation. This threshold can be set -by changing the \b smpi/send-is-detached-thresh item. The default value is 65536. +by changing the @b smpi/send-is-detached-thresh item. The default value is 65536. -\subsection options_model_smpi_collectives Simulating MPI collective algorithms +@subsection options_model_smpi_collectives Simulating MPI collective algorithms SMPI implements more than 100 different algorithms for MPI collective communication, to accurately -simulate the behavior of most of the existing MPI libraries. The \b smpi/coll-selector item can be used +simulate the behavior of most of the existing MPI libraries. The @b smpi/coll-selector item can be used to use the decision logic of either OpenMPI or MPICH libraries (values: ompi or mpich, by default SMPI uses naive version of collective operations). Each collective operation can be manually selected with a -\b smpi/collective_name:algo_name. Available algorithms are listed in \ref SMPI_use_colls . +@b smpi/collective_name:algo_name. Available algorithms are listed in @ref SMPI_use_colls . -\subsection options_model_smpi_iprobe smpi/iprobe: Inject constant times for calls to MPI_Iprobe +@subsection options_model_smpi_iprobe smpi/iprobe: Inject constant times for calls to MPI_Iprobe -\b Default value: 0.0001 +@b Default value: 0.0001 -The behavior and motivation for this configuration option is identical with \a smpi/test, see -Section \ref options_model_smpi_test for details. +The behavior and motivation for this configuration option is identical with @a smpi/test, see +Section @ref options_model_smpi_test for details. -\subsection options_model_smpi_iprobe_cpu_usage smpi/iprobe-cpu-usage: Reduce speed for iprobe calls +@subsection options_model_smpi_iprobe_cpu_usage smpi/iprobe-cpu-usage: Reduce speed for iprobe calls -\b Default value: 1 (no change from default behavior) +@b Default value: 1 (no change from default behavior) MPI_Iprobe calls can be heavily used in applications. To account correctly for the energy cores spend probing, it is necessary to reduce the load that these calls cause inside @@ -1089,32 +1092,32 @@ For instance, we measured a max power consumption of 220 W for a particular appl only 180 W while this application was probing. Hence, the correct factor that should be passed to this option would be 180/220 = 0.81. -\subsection options_model_smpi_init smpi/init: Inject constant times for calls to MPI_Init +@subsection options_model_smpi_init smpi/init: Inject constant times for calls to MPI_Init -\b Default value: 0 +@b Default value: 0 -The behavior for this configuration option is identical with \a smpi/test, see -Section \ref options_model_smpi_test for details. +The behavior for this configuration option is identical with @a smpi/test, see +Section @ref options_model_smpi_test for details. -\subsection options_model_smpi_ois smpi/ois: Inject constant times for asynchronous send operations +@subsection options_model_smpi_ois smpi/ois: Inject constant times for asynchronous send operations -This configuration option works exactly as \a smpi/os, see Section \ref options_model_smpi_os. -Of course, \a smpi/ois is used to account for MPI_Isend instead of MPI_Send. +This configuration option works exactly as @a smpi/os, see Section @ref options_model_smpi_os. +Of course, @a smpi/ois is used to account for MPI_Isend instead of MPI_Send. -\subsection options_model_smpi_os smpi/os: Inject constant times for send operations +@subsection options_model_smpi_os smpi/os: Inject constant times for send operations In several network models such as LogP, send (MPI_Send, MPI_Isend) and receive (MPI_Recv) operations incur costs (i.e., they consume CPU time). SMPI can factor these costs in as well, but the user has to configure SMPI accordingly as these values may vary by machine. This can be done by using smpi/os for MPI_Send operations; for MPI_Isend and -MPI_Recv, use \a smpi/ois and \a smpi/or, respectively. These work exactly as -\a smpi/ois. +MPI_Recv, use @a smpi/ois and @a smpi/or, respectively. These work exactly as +@a smpi/ois. -\a smpi/os can consist of multiple sections; each section takes three values, for example: +@a smpi/os can consist of multiple sections; each section takes three values, for example: -\verbatim +@verbatim 1:3:2;10:5:1 -\endverbatim +@endverbatim Here, the sections are divided by ";" (that is, this example contains two sections). Furthermore, each section consists of three values. @@ -1128,7 +1131,7 @@ Furthermore, each section consists of three values. be charged, no matter what the size of the message. In the first section above, this value is "3". -3. The third value is the \a per-byte cost. That is, it is charged for every +3. The third value is the @a per-byte cost. That is, it is charged for every byte of the message (incurring cost messageSize*cost_per_byte) and hence accounts also for larger messages. In the first section of the example above, this value is "2". @@ -1139,23 +1142,23 @@ the second section will be used, not the first, as the first value of the second section is closer to the message size. Hence, a message of size 11 incurs the following cost inside MPI_Send: -\verbatim +@verbatim 5+11*1 -\endverbatim +@endverbatim As 5 is the startup cost and 1 is the cost per byte. -\note +@note The order of sections can be arbitrary; they will be ordered internally. -\subsection options_model_smpi_or smpi/or: Inject constant times for receive operations +@subsection options_model_smpi_or smpi/or: Inject constant times for receive operations -This configuration option works exactly as \a smpi/os, see Section \ref options_model_smpi_os. -Of course, \a smpi/or is used to account for MPI_Recv instead of MPI_Send. +This configuration option works exactly as @a smpi/os, see Section @ref options_model_smpi_os. +Of course, @a smpi/or is used to account for MPI_Recv instead of MPI_Send. -\subsection options_model_smpi_test smpi/test: Inject constant times for calls to MPI_Test +@subsection options_model_smpi_test smpi/test: Inject constant times for calls to MPI_Test -\b Default value: 0.0001 +@b Default value: 0.0001 By setting this option, you can control the amount of time a process sleeps when MPI_Test() is called; this is important, because SimGrid normally only @@ -1165,14 +1168,14 @@ break-condition. Here is an example: -\code{.unparsed} +@code{.unparsed} while(!flag) { MPI_Test(request, flag, status); ... } -\endcode +@endcode -\note +@note Internally, in order to speed up execution, we use a counter to keep track on how often we already checked if the handle is now valid or not. Hence, we actually use counter*SLEEP_TIME, that is, the time MPI_Test() causes the process @@ -1181,9 +1184,9 @@ Here is an example: also disable this behavior for MPI_Iprobe. -\subsection options_model_smpi_shared_malloc smpi/shared-malloc: Factorize malloc()s +@subsection options_model_smpi_shared_malloc smpi/shared-malloc: Factorize malloc()s -\b Default: global +@b Default: global If your simulation consumes too much memory, you may want to modify your code so that the working areas are shared by all MPI ranks. For @@ -1197,14 +1200,14 @@ section of the SMPI CourseWare (see Activity #2.2 of the pointed assignment). In practice, change the call to malloc() and free() into SMPI_SHARED_MALLOC() and SMPI_SHARED_FREE(). -SMPI provides 2 algorithms for this feature. The first one, called \c +SMPI provides 2 algorithms for this feature. The first one, called @c local, allocates one bloc per call to SMPI_SHARED_MALLOC() in your code (each call location gets its own bloc) and this bloc is shared amongst all MPI ranks. This is implemented with the shm_* functions to create a new POSIX shared memory object (kept in RAM, in /dev/shm) for each shared bloc. -With the \c global algorithm, each call to SMPI_SHARED_MALLOC() +With the @c global algorithm, each call to SMPI_SHARED_MALLOC() returns a new adress, but it only points to a shadow bloc: its memory area is mapped on a 1MiB file on disk. If the returned bloc is of size N MiB, then the same file is mapped N times to cover the whole bloc. @@ -1212,7 +1215,7 @@ At the end, no matter how many SMPI_SHARED_MALLOC you do, this will only consume 1 MiB in memory. You can disable this behavior and come back to regular mallocs (for -example for debugging purposes) using \c "no" as a value. +example for debugging purposes) using @c "no" as a value. If you want to keep private some parts of the buffer, for instance if these parts are used by the application logic and should not be corrupted, you @@ -1220,9 +1223,9 @@ can use SMPI_PARTIAL_SHARED_MALLOC(size, offsets, offsets_count). As an example, -\code{.C} +@code{.C} mem = SMPI_PARTIAL_SHARED_MALLOC(500, {27,42 , 100,200}, 2); -\endcode +@endcode will allocate 500 bytes to mem, such that mem[27..41] and mem[100..199] are shared and other area remain private. @@ -1236,43 +1239,48 @@ entry per Mb of malloced data instead of one entry per 4k. To activate this, you must mount a hugetlbfs on your system and allocate at least one huge page: -\code{.sh} +@code{.sh} mkdir /home/huge sudo mount none /home/huge -t hugetlbfs -o rw,mode=0777 sudo sh -c 'echo 1 > /proc/sys/vm/nr_hugepages' # echo more if you need more -\endcode +@endcode Then, you can pass the option --cfg=smpi/shared-malloc-hugepage:/home/huge to smpirun to actually activate the huge page support in shared mallocs. -\subsection options_model_smpi_wtime smpi/wtime: Inject constant times for calls to MPI_Wtime - -\b Default value: 0 +@subsection options_model_smpi_wtime smpi/wtime: Inject constant times for calls to MPI_Wtime, gettimeofday and clock_gettime -By setting this option, you can control the amount of time a process sleeps -when MPI_Wtime() is called; this is important, because SimGrid normally only -advances the time while communication is happening and thus, -MPI_Wtime will not add to the time, resulting in a deadlock if used as a -break-condition. +@b Default value: 10 ns -Here is an example: +This option controls the amount of (simulated) time spent in calls to +MPI_Wtime(), gettimeofday() and clock_gettime(). If you set this value +to 0, the simulated clock is not advanced in these calls, which leads +to issue if your application contains such a loop: -\code{.unparsed} +@code{.unparsed} while(MPI_Wtime() < some_time_bound) { - ... + /* some tests, with no communication nor computation */ } -\endcode +@endcode -If the time is never advanced, this loop will clearly never end as MPI_Wtime() -always returns the same value. Hence, pass a (small) value to the smpi/wtime -option to force a call to MPI_Wtime to advance the time as well. +When the option smpi/wtime is set to 0, the time advances only on +communications and computations, so the previous code results in an +infinite loop: the current [simulated] time will never reach @c +some_time_bound. This infinite loop is avoided when that option is +set to a small amount, as it is by default since SimGrid v3.21. +Note that if your application does not contain any loop depending on +the current time only, then setting this option to a non-zero value +will slow down your simulations by a tiny bit: the simulation loop has +to be broken and reset each time your code ask for the current time. +If the simulation speed really matters to you, you can avoid this +extra delay by setting smpi/wtime to 0. -\section options_generic Configuring other aspects of SimGrid +@section options_generic Configuring other aspects of SimGrid -\subsection options_generic_clean_atexit Cleanup before termination +@subsection options_generic_clean_atexit Cleanup before termination -The C / C++ standard contains a function called \b [atexit](http://www.cplusplus.com/reference/cstdlib/atexit/). +The C / C++ standard contains a function called @b [atexit](http://www.cplusplus.com/reference/cstdlib/atexit/). atexit registers callbacks, which are called just before the program terminates. By setting the configuration option clean-atexit to 1 (true), a callback @@ -1280,28 +1288,45 @@ is registered and will clean up some variables and terminate/cleanup the tracing TODO: Add when this should be used. -\subsection options_generic_path XML file inclusion path +@subsection options_generic_path Profile files' search path It is possible to specify a list of directories to search into for the -\ tag in XML files by using the \b path configuration +trace files (see @ref pf_trace) by using the @b path configuration item. To add several directory to the path, set the configuration -item several times, as in \verbatim +item several times, as in @verbatim --cfg=path:toto --cfg=path:tutu -\endverbatim +@endverbatim + +@subsection options_generic_breakpoint Set a breakpoint + +@verbatim +--cfg=simix/breakpoint:3.1416 +@endverbatim + +This configuration option sets a breakpoint: when the simulated clock reaches +the given time, a SIGTRAP is raised. This can be used to stop the execution and +get a backtrace with a debugger. + +It is also possible to set the breakpoint from inside the debugger, by writing +in global variable simgrid::simix::breakpoint. For example, with gdb: + +@verbatim +set variable simgrid::simix::breakpoint = 3.1416 +@endverbatim -\subsection options_generic_exit Behavior on Ctrl-C +@subsection options_generic_exit Behavior on Ctrl-C By default, when Ctrl-C is pressed, the status of all existing simulated processes is displayed before exiting the simulation. This is very useful to debug your code, but it can reveal troublesome in some cases (such as when the amount of processes becomes really big). This behavior is disabled -when \b verbose-exit is set to 0 (it is to 1 by default). +when @b verbose-exit is set to 0 (it is to 1 by default). -\subsection options_exception_cutpath Truncate local path from exception backtrace +@subsection options_exception_cutpath Truncate local path from exception backtrace -\verbatim ---cfg=exceptions/cutpath:1 -\endverbatim +@verbatim +--cfg=exception/cutpath:1 +@endverbatim This configuration option is used to remove the path from the backtrace shown when an exception is thrown. This is mainly useful for @@ -1310,8 +1335,8 @@ thus failing as we are currently comparing output. Clearly, the path used on different machines are almost guaranteed to be different and hence, the output would mismatch, causing the test to fail. -\section options_log Logging Configuration +@section options_log Logging Configuration -It can be done by using XBT. Go to \ref XBT_log for more details. +It can be done by using XBT. Go to @ref XBT_log for more details. */