.. note::
The full list can be retrieved by passing ``--help`` and
- ``--help-cfg`` to an executable that uses SimGrid.
-
-- **clean-atexit:** :ref:`cfg=clean-atexit`
+ ``--help-cfg`` to an executable that uses SimGrid. Try passing
+ ``help`` as a value to get the list of values accepted by a given
+ option. For example, ``--cfg=plugin:help`` will give you the list
+ of plugins available in your installation of SimGrid.
- **contexts/factory:** :ref:`cfg=contexts/factory`
- **contexts/guard-size:** :ref:`cfg=contexts/guard-size`
- **cpu/model:** :ref:`options_model_select`
- **cpu/optim:** :ref:`Cpu Optimization Level <options_model_optim>`
+- **debug/breakpoint:** :ref:`cfg=debug/breakpoint`
+- **debug/clean-atexit:** :ref:`cfg=debug/clean-atexit`
+- **debug/verbose-exit:** :ref:`cfg=debug/verbose-exit`
+
- **exception/cutpath:** :ref:`cfg=exception/cutpath`
- **host/model:** :ref:`options_model_select`
- **model-check/checkpoint:** :ref:`cfg=model-check/checkpoint`
- **model-check/communications-determinism:** :ref:`cfg=model-check/communications-determinism`
- **model-check/dot-output:** :ref:`cfg=model-check/dot-output`
-- **model-check/hash:** :ref:`cfg=model-checker/hash`
- **model-check/max-depth:** :ref:`cfg=model-check/max-depth`
- **model-check/property:** :ref:`cfg=model-check/property`
- **model-check/reduction:** :ref:`cfg=model-check/reduction`
- **model-check/replay:** :ref:`cfg=model-check/replay`
- **model-check/send-determinism:** :ref:`cfg=model-check/send-determinism`
-- **model-check/sparse-checkpoint:** :ref:`cfg=model-check/sparse-checkpoint`
- **model-check/termination:** :ref:`cfg=model-check/termination`
- **model-check/timeout:** :ref:`cfg=model-check/timeout`
- **model-check/visited:** :ref:`cfg=model-check/visited`
- **path:** :ref:`cfg=path`
- **plugin:** :ref:`cfg=plugin`
-- **simix/breakpoint:** :ref:`cfg=simix/breakpoint`
-
- **storage/max_file_descriptors:** :ref:`cfg=storage/max_file_descriptors`
- **surf/precision:** :ref:`cfg=surf/precision`
- **For collective operations of SMPI,** please refer to Section :ref:`cfg=smpi/coll-selector`
- **smpi/async-small-thresh:** :ref:`cfg=smpi/async-small-thresh`
+- **smpi/buffering:** :ref:`cfg=smpi/buffering`
- **smpi/bw-factor:** :ref:`cfg=smpi/bw-factor`
- **smpi/coll-selector:** :ref:`cfg=smpi/coll-selector`
- **smpi/comp-adjustment-file:** :ref:`cfg=smpi/comp-adjustment-file`
- **Tracing configuration options** can be found in Section :ref:`tracing_tracing_options`
- **storage/model:** :ref:`options_model_select`
-- **verbose-exit:** :ref:`cfg=verbose-exit`
- **vm/model:** :ref:`options_model_select`
without corrective factors. The timings of small messages are thus
poorly modeled. This model is described in `A Network Model for
Simulation of Grid Application
- <ftp://ftp.ens-lyon.fr/pub/LIP/Rapports/RR/RR2002/RR2002-40.ps.gz>`_.
- - **Reno/Reno2/Vegas:** Models from Steven H. Low using lagrange_solve instead of
- lmm_solve (experts only; check the code for more info).
- - **NS3** (only available if you compiled SimGrid accordingly):
+ <https://hal.inria.fr/inria-00071989/document>`_.
+ - **ns-3** (only available if you compiled SimGrid accordingly):
Use the packet-level network
- simulators as network models (see :ref:`pls_ns3`).
+ simulators as network models (see :ref:`model_ns3`).
This model can be :ref:`further configured <options_pls>`.
- ``cpu/model``: specify the used CPU model. We have only one model
this mailbox will have this behavior regardless of the message size.
This value needs to be smaller than or equals to the threshold set at
-@ref options_model_smpi_detached , because asynchronous messages are
-meant to be detached as well.
+:ref:`cfg=smpi/send-is-detached-thresh`, because asynchronous messages
+are meant to be detached as well.
.. _options_pls:
-Configuring NS3
-^^^^^^^^^^^^^^^
+Configuring ns-3
+^^^^^^^^^^^^^^^^
-**Option** ``ns3/TcpModel`` **Default:** "default" (NS3 default)
+**Option** ``ns3/TcpModel`` **Default:** "default" (ns-3 default)
-When using NS3, there is an extra item ``ns3/TcpModel``, corresponding
+When using ns-3, there is an extra item ``ns3/TcpModel``, corresponding
to the ``ns3::TcpL4Protocol::SocketType`` configuration item in
-NS3. The only valid values (enforced on the SimGrid side) are
-'default' (no change to the NS3 configuration), 'NewReno' or 'Reno' or
+ns-3. The only valid values (enforced on the SimGrid side) are
+'default' (no change to the ns-3 configuration), 'NewReno' or 'Reno' or
'Tahoe'.
Configuring the Storage model
Safety properties are expressed as assertions using the function
:cpp:func:`void MC_assert(int prop)`.
+.. _cfg=smpi/buffering:
+
+Specifying the MPI buffering behavior
+.....................................
+
+**Option** ``smpi/buffering`` **Default:** infty
+
+Buffering in MPI has a huge impact on the communication semantic. For example,
+standard blocking sends are synchronous calls when the system buffers are full
+while these calls can complete immediately without even requiring a matching
+receive call for small messages sent when the system buffers are empty.
+
+In SMPI, this depends on the message size, that is compared against two thresholds:
+
+- if (size < :ref:`smpi/async-small-thresh <cfg=smpi/async-small-thresh>`) then
+ MPI_Send returns immediately, even if the corresponding receive has not be issued yet.
+- if (:ref:`smpi/async-small-thresh <cfg=smpi/async-small-thresh>` < size < :ref:`smpi/send-is-detached-thresh <cfg=smpi/send-is-detached-thresh>`) then
+ MPI_Send returns as soon as the corresponding receive has been issued. This is known as the eager mode.
+- if (:ref:`smpi/send-is-detached-thresh <cfg=smpi/send-is-detached-thresh>` < size) then
+ MPI_Send returns only when the message has actually been sent over the network. This is known as the rendez-vous mode.
+
+The ``smpi/buffering`` option gives an easier interface to choose between these semantics. It can take two values:
+
+- **zero:** means that buffering should be disabled. Blocking communications are actually blocking.
+- **infty:** means that buffering should be made infinite. Blocking communications are non-blocking.
+
.. _cfg=model-check/property:
Specifying a liveness property
communication determinism mode of the model-checker which checks
determinism properties of the communications of an application.
-.. _cfg=model-check/sparse-checkpoint:
-
-Incremental Checkpoints
-.......................
-
-When the model-checker is configured to take a snapshot of each
-explored state (with the ``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 ``model-check/sparse-checkpoint`` option item can be set to
-**yes** 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 is used in the same snapshot), the same copy of the block
-will be shared leading to a reduction of the memory footprint.
-
-For many applications, this option considerably reduces the memory
-consumption. In somes cases, the model-checker might be slightly
-slower because of the time taken to manage the metadata about the
-blocks. In other cases however, this snapshotting strategy will be
-much faster by reducing the cache consumption. When the memory
-consumption is important, by avoiding to hit the swap or reducing the
-swap usage, this option might be much faster than the basic
-snapshotting strategy.
-
-This option is currently disabled by default.
-
Verification Performance Considerations
.......................................
consumption of the snapshots to be @f$ @mbox{number of processes}
@times @mbox{stack size} @times @mbox{number of states} @f$.
-The ``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:`contexts/guard-size <cfg=contexts/guard-size>`).
-.. _cfg=model-checker/hash:
-
-State Hashing
-.............
-
-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 ``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.
-
.. _cfg=model-check/replay:
Replaying buggy execution paths out of the model-checker
[ 0.000000] (0:@) Executed transitions = 46
The interesting line is ``Path = 1/3;1/4``, which means that you should use
-`--cfg=model-check/replay:1/3;1/4`` to replay your application on the buggy
-execution path. The other options should be the same (but the model-checker
-should be disabled). Note that format and meaning of the path may change between
-different releases.
+``--cfg=model-check/replay:1/3;1/4`` to replay your application on the buggy
+execution path. All options (but the model-checker related ones) must
+remain the same. In particular, if you ran your application with
+``smpirun -wrapper simgrid-mc``, then do it again. Remove all
+MC-related options, keep the other ones and add
+``--cfg=model-check/replay``.
+
+Currently, if the path is of the form ``X;Y;Z``, each number denotes
+the actor's pid that is selected at each indecision point. If it's of
+the form ``X/a;Y/b``, the X and Y are the selected pids while the a
+and b are the return values of their simcalls. In the previouse
+example, ``1/3;1/4``, you can see from the full output that the actor
+1 is doing MC_RANDOM simcalls, so the 3 and 4 simply denote the values
+that these simcall return.
Configuring the User Code Virtualization
----------------------------------------
bandwidth of the link).
An experimental script to compute these factors is available online. See
-http://simgrid.gforge.inria.fr/contrib/smpi-calibration-doc.html
-http://simgrid.gforge.inria.fr/contrib/smpi-saturation-doc.html
+https://framagit.org/simgrid/platform-calibration/
+https://simgrid.org/contrib/smpi-saturation-doc.html
.. _cfg=smpi/display-timing:
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` because the message is not
+:ref:`cfg=smpi/async-small-thresh` 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.
Other Configurations
--------------------
-.. _cfg=clean-atexit:
+.. _cfg=debug/clean-atexit:
Cleanup at Termination
......................
-**Option** ``clean-atexit`` **default:** on
+**Option** ``debug/clean-atexit`` **default:** on
If your code is segfaulting during its finalization, it may help to
disable this option to request SimGrid to not attempt any cleanups at
item. To add several directory to the path, set the configuration
item several times, as in ``--cfg=path:toto --cfg=path:tutu``
-.. _cfg=simix/breakpoint:
+.. _cfg=debug/breakpoint:
Set a Breakpoint
................
-**Option** ``simix/breakpoint`` **default:** unset
+**Option** ``debug/breakpoint`` **default:** unset
This configuration option sets a breakpoint: when the simulated clock
reaches the given time, a SIGTRAP is raised. This can be used to stop
set variable simgrid::simix::breakpoint = 3.1416
-.. _cfg=verbose-exit:
+.. _cfg=debug/verbose-exit:
Behavior on Ctrl-C
..................
-**Option** ``verbose-exit`` **default:** on
+**Option** ``debug/verbose-exit`` **default:** on
By default, when Ctrl-C is pressed, the status of all existing actors
is displayed before exiting the simulation. This is very useful to