\section options_model Configuring the platform models
+\anchor options_storage_model
+\anchor options_vm_model
\subsection options_model_select Selecting the platform models
-SimGrid comes with several network and CPU models built in, and you
+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
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 workstation/model: specify the used workstation 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_workstation/model: specify the workstation 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
Concerning the CPU, we have only one model for now:
- \b Cas01: Simplistic CPU model (time=size/power)
-The workstation concept is the aggregation of a CPU with a network
+The host concept is the aggregation of a CPU with a network
card. Three models exists, but actually, only 2 of them are
interesting. The "compound" one is simply due to the way our internal
code is organized, and can easily be ignored. So at the end, you have
-two workstation models: The default one allows to aggregate an
+two host models: The default one allows to aggregate an
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 workstation model. Currently, CPU:Cas01 and
+ - \b default: Default host model. Currently, CPU:Cas01 and
network:LV08 (with cross traffic enabled)
- - \b compound: Workstation 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: Workstation model somehow similar to Cas01+CM02 but
+ - \b ptask_L07: Host model somehow similar to Cas01+CM02 but
allowing parallel tasks
+\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).
+
+Plugins can for instance define own classes that inherit from
+existing classes (for instance, a class "CpuEnergy" inherits from
+"Cpu" to assess energy consumption).
+
+The plugin connects to the code by registering callbacks using
+``surf_callback_register`` (see file ``src/surf/plugins/energy.cpp`` for details).
+
+\verbatim
+ --cfg=plugin:Energy
+\endverbatim
+
+\note
+ This option is case-sensitive: Energy and energy are not the same!
+
\subsection options_model_optim Optimization level of the platform models
The network and CPU models that are based on lmm_solve (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 workstation model this option is activated by default.
+Note that with the default host model this option is activated by default.
\subsubsection options_model_network_coord Coordinated-based network models
so that you don't have to give <tt>--cfg=model-check:1</tt> in
addition.
+\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,
+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.
+
+By default, no state is snapshotted and cycles cannot be detected.
+
+\subsection options_modelchecking_termination model-check/termination, Non termination detection
+
+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.
+
+This only works in safety mode.
+
+This options is disabled by default.
+
+\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
+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
+
+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
By default, the model-checker does not handle timeout conditions: the `wait`
application, the stack will silently overflow on other parts of the
memory.
-\subsection options_recordreplay Record/replay
+\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
+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
+the hashes are identical.
+
+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)
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
simulations. For additional details about this and all tracing
options, check See the \ref tracing_tracing_options.
+\section options_msg Configuring 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,
+for debugging purposes, one may want to know what the other host is/was
+doing. This option shows a backtrace of the other process.
+
+Enable this option by adding
+
+\verbatim
+--cfg=msg/debug_multiple_use:on
+\endverbatim
+
\section options_smpi Configuring SMPI
The SMPI interface provides several specific configuration items.
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
-impacts badly the simulation performance. It specify a threshold (in
-second) under which the execution chunks are not reported to the
-simulation kernel (default value: 1e-6). Please note that in some
-circonstances, this optimization can hinder the simulation accuracy.
+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
+ The option smpi/cpu_threshold ignores any computation time spent
+ 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.
In some cases, however, one may wish to disable simulation of
application computation. This is the case when SMPI is used not to
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
+ 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
+\b Default: 0 (false)
+
Most of the time, you run MPI code through SMPI to compute the time it
would take to run it on a platform that you don't have. But since the
code is run through the \c smpirun script, you don't have any control
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
+\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_global smpi/privatize_global_variables: Automatic privatization of global variables
MPI executables are meant to be executed in separated processes, but SMPI is
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_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.
+
+\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.
+
+\a smpi/os can consist of multiple sections; each section takes three values, for example:
+
+\verbatim
+ 1:3:2;10:5:1
+\endverbatim
+
+Here, the sections are divided by ";" (that is, this example contains two sections).
+Furthermore, each section consists of three values.
+
+1. The first value denotes the minimum size for this section to take effect;
+ read it as "if message size is greater than this value (and other section has a larger
+ first value that is also smaller than the message size), use this".
+ In the first section above, this value is "1".
+
+2. The second value is the startup time; this is a constant value that will always
+ 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
+ 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".
+
+Now, SMPI always checks which section it should take for a given message; that is,
+if a message of size 11 is sent with the configuration of the example above, only
+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
+ 5+11*1
+\endverbatim
+
+%As 5 is the startup cost and 1 is the cost per byte.
+
+\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
+
+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
\b Default value: 0.0001
to sleep increases linearly with the number of previously failed testk.
+\subsection options_model_smpi_use_shared_malloc smpi/use_shared_malloc: Use shared memory
+
+\b Default: 1
+
+SMPI can use shared memory by calling shm_* functions; this might speed up the simulation.
+This opens or creates a new POSIX shared memory object, kept in RAM, in /dev/shm.
+
+If you want to disable this behavior, set the value to 0.
+
\subsection options_model_smpi_wtime smpi/wtime: Inject constant times for calls to MPI_Wtime
\b Default value: 0
for the moment (May 2015).
\note
- \b Please \b note: You can also pass the command-line option "\b --help" and
+ \b Please \b note: You can also pass the command-line option "--help" and
"--help-cfg" to an executable that uses simgrid.
- \c clean_atexit: \ref options_generic_clean_atexit
- \c gtnets/jitter: \ref options_pls
- \c gtnets/jitter_seed: \ref options_pls
+- \c host/model: \ref options_model_select
+
- \c maxmin/precision: \ref options_model_precision
- \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/communications_determinism: \ref options_modelchecking_send_determinism
+- \c model-check/send_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/reduction: \ref options_modelchecking_reduction
- \c model-check/replay: \ref options_modelchecking_recordreplay
- \c model-check/send_determinism: \ref options_modelchecking_sparse_checkpoint
-- \c model-check/snapshot_fds: \ref options_modelchecking_snapshot_fds
- \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 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 surf/nthreads: \ref options_model_nthreads
- \c surf/precision: \ref options_model_precision
- \c <b>Tracing configuration options can be found in Section \ref tracing_tracing_options</b>.
- \c storage/model: \ref options_storage_model
-- \c path: \ref options_generic_path
-- \c plugin: \ref options_generic_plugin
- \c verbose-exit: \ref options_generic_exit
- \c vm_workstation/model: \ref options_vm_workstation_model
-- \c workstation/model: \ref options_model_select
\subsection options_index_smpi_coll Index of SMPI collective algorithms options
-- \c smpi/allgather: \ref options_model_smpi_coll_allgather
-- \c smpi/allgatherv: \ref options_model_smpi_coll_allgatherv
-- \c smpi/allreduce: \ref options_model_smpi_coll_allreduce
-- \c smpi/alltoall: \ref options_model_smpi_coll_alltoall
-- \c smpi/alltoallv: \ref options_model_smpi_coll_alltoallv
-- \c smpi/barrier: \ref options_model_smpi_coll_barrier
-- \c smpi/bcast: \ref options_model_smpi_coll_bcast
-- \c smpi/gather: \ref options_model_smpi_coll_gather
-- \c smpi/reduce: \ref options_model_smpi_coll_reduce
-- \c smpi/reduce_scatter: \ref options_model_smpi_coll_reduce_scatter
-- \c smpi/scatter: \ref options_model_smpi_coll_scatter
+
+TODO: All available collective algorithms will be made available via the ``smpirun --help-coll`` command.
*/
