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
- \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
\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
\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>mmap</b> or <b>yes</b> (default when using smpirun):
+ Runtime automatic switching of the data segments.
+ - <b>dlopen</b> (faster but less tested): Link multiple times against the binary.
\warning
This configuration option cannot be set in your platform file. You can only
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
\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
