/*! \page options Configure SimGrid
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+\htmlinclude graphical-toc.svg
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+</div>
+<script>
+document.getElementById("Config").style="opacity:0.93999999;fill:#ff0000;fill-opacity:0.1;stroke:#000000;stroke-width:0.35277778;stroke-linecap:round;stroke-linejoin:round;stroke-miterlimit:4;stroke-dasharray:none;stroke-dashoffset:0;stroke-opacity:1";
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+
A number of options can be given at runtime to change the default
SimGrid behavior. For a complete list of all configuration options
accepted by the SimGrid version used in your simulator, simply pass
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
@code
#include <xbt/config.h>
-extern xbt_cfg_t _sg_cfg_set;
-
int main(int argc, char *argv[]) {
SD_init(&argc, argv);
/* Prefer MSG_config() if you use MSG!! */
- xbt_cfg_set_parse(_sg_cfg_set,"Item:Value");
+ xbt_cfg_set_parse("Item:Value");
// Rest of your code
}
- \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/parallel-threshold: \ref options_virt_parallel
- \c contexts/stack-size: \ref options_virt_stacksize
- \c contexts/synchro: \ref options_virt_parallel
- \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 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
- \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
<a href="http://mescal.imag.fr/membres/arnaud.legrand/articles/simutools09.pdf">Accuracy Study and Improvement of Network Simulation in the SimGrid Framework</a>.
- \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)
+ (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.
\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).
-
-The plugin connects to the code by registering callbacks using
-``signal.connect(callback)`` (see file ``src/surf/plugins/energy.cpp`` for
-details).
+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:
\verbatim
- --cfg=plugin:Energy
+ --cfg=plugin:host_energy
\endverbatim
-\note
- This option is case-sensitive: Energy and energy are not the same!
+Here is the full list of plugins that can be activated this way:
+
+ - \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
\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
+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
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
(this configuration item is experimental and may change or disapear)
\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.
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
graph of the model-checker. If this limit is reached, a logging message is
- \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
\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
-<a href="https://hal.inria.fr/hal-01415484">SMPI publication</a>.
-SimGrid provides two ways of automatically privatizing the globals,
-and this option allows to choose between them.
-
- - <b>no</b> (default): Do not automatically privatize variables.
- - <b>mmap</b> or <b>yes</b>: 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).
- - <b>dlopen</b>: 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
- <a href="https://lwn.net/Articles/415889/">punch holes</a>
- 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).
+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
+<a href="https://hal.inria.fr/hal-01415484">SMPI publication</a> 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.
+
+ - <b>no</b> (default when not using smpirun): Do not automatically privatize variables.
+ Pass \c -no-privatize to smpirun to disable this feature.
+ - <b>dlopen</b> or <b>yes</b> (default when using smpirun): Link multiple times against the binary.
+ - <b>mmap</b> (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
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
-\<include\> 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
--cfg=path:toto --cfg=path:tutu
\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
By default, when Ctrl-C is pressed, the status of all existing
\subsection options_exception_cutpath Truncate local path from exception backtrace
\verbatim
---cfg=exceptions/cutpath:1
+--cfg=exception/cutpath:1
\endverbatim
This configuration option is used to remove the path from the
