type the following on the command-line:
.. code-block:: shell
-
+
my_simulator --cfg=Item:Value (other arguments)
Several ``--cfg`` command line arguments can naturally be used. If you
you have your argument between ').
Another solution is to use the ``<config>`` tag in the platform file. The
-only restriction is that this tag must occure before the first
+only restriction is that this tag must occur before the first
platform element (be it ``<zone>``, ``<cluster>``, ``<peer>`` or whatever).
The ``<config>`` tag takes an ``id`` attribute, but it is currently
ignored so you don't really need to pass it. The important part is that
file:
.. code-block:: xml
-
+
<config>
<prop id="Item" value="Value"/>
</config>
with :cpp:func:`simgrid::s4u::Engine::set_config` or :cpp:func:`MSG_config`.
.. code-block:: cpp
-
+
#include <simgrid/s4u.hpp>
int main(int argc, char *argv[]) {
simgrid::s4u::Engine e(&argc, argv);
-
+
e->set_config("Item:Value");
-
+
// Rest of your code
}
.. _options_list:
-
+
Existing Configuration Items
----------------------------
.. 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/record:** :ref:`cfg=model-check/record`
- **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`
models for all existing resources.
- ``network/model``: specify the used network model. Possible values:
-
+
- **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). Described in `Accuracy Study and Improvement of Network
Simulation in the SimGrid Framework
- <http://mescal.imag.fr/membres/arnaud.legrand/articles/simutools09.pdf>`_.
+ <http://mescal.imag.fr/membres/arnaud.legrand/articles/simutools09.pdf>`_.
- **Constant:** Simplistic network model where all communication
take a constant time (one second). This model provides the lowest
realism, but is (marginally) faster.
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
for now:
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 host models: The default one allows to aggregate
+ end, you have two host models: The default one allows aggregation of
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.
-
+
- **default:** Default host model. Currently, CPU:Cas01 and
network:LV08 (with cross traffic enabled)
- **compound:** Host model that is automatically chosen if
configurations.
- items ``network/optim`` and ``cpu/optim`` (both default to 'Lazy'):
-
+
- **Lazy:** Lazy action management (partial invalidation in lmm +
heap in action remaining).
- **TI:** Trace integration. Highly optimized mode when using
now).
- **Full:** Full update of remaining and variables. Slow but may be
useful when debugging.
-
+
- items ``network/maxmin-selective-update`` and
``cpu/maxmin-selective-update``: configure whether the underlying
should be lazily updated or not. It should have no impact on the
and you should use the last one, which is the maximal size.
.. code-block:: shell
-
+
cat /proc/sys/net/ipv4/tcp_rmem # gives the sender window
cat /proc/sys/net/ipv4/tcp_wmem # gives the receiver window
.. _cfg=network/bandwidth-factor:
.. _cfg=network/latency-factor:
.. _cfg=network/weight-S:
-
+
Correcting Important Network Parameters
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
.. _cfg=smpi/async-small-thresh:
-Simulating Asyncronous Send
-^^^^^^^^^^^^^^^^^^^^^^^^^^^
+Simulating Asynchronous Send
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-(this configuration item is experimental and may change or disapear)
+(this configuration item is experimental and may change or disappear)
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
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
Activating Plugins
------------------
-SimGrid plugins allow to extend the framework without changing its
+SimGrid plugins allow one 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
computations. More details in @ref plugin_energy.
- **link_energy:** keeps track of the energy dissipated by
communications. More details in @ref SURF_plugin_energy.
- - **host_load:** keeps track of the computational load.
+ - **host_load:** keeps track of the computational load.
More details in @ref plugin_load.
.. _options_modelchecking:
-
+
Configuring the Model-Checking
------------------------------
be executed using the simgrid-mc wrapper:
.. code-block:: shell
-
+
simgrid-mc ./my_program
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
..............................
If you want to specify liveness properties, you have to pass them on
the command line, specifying the name of the file containing the
-property, as formatted by the ltl2ba program.
-
+property, as formatted by the ltl2ba program. Note that ltl2ba is not
+part of SimGrid and must be installed separatly.
.. code-block:: shell
-
+
simgrid-mc ./my_program --cfg=model-check/property:<filename>
.. _cfg=model-check/checkpoint:
-
+
Going for Stateful Verification
...............................
Size of Cycle Detection Set
...........................
-In order to detect cycles, the model-checker needs to check if a new
+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. For
-that, the model-checker can take a snapshot of each visited state:
+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 ``model-checker/max-depth`` can set the maximum depth of the
-exploration graph of the model-checker. If this limit is reached, a
+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.
Handling of Timeouts
....................
-By default, the model-checker does not handle timeout conditions: the `wait`
+By default, the model checker does not handle timeout conditions: the `wait`
operations never time out. With the ``model-check/timeout`` configuration item
-set to **yes**, the model-checker will explore timeouts of `wait` operations.
+set to **yes**, the model checker will explore timeouts of `wait` operations.
.. _cfg=model-check/communications-determinism:
.. _cfg=model-check/send-determinism:
The ``model-check/communications-determinism`` and
``model-check/send-determinism`` items can be used to select the
-communication determinism mode of the model-checker which checks
+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/record:
.. _cfg=model-check/replay:
-Record/Replay of Verification
-.............................
+Replaying buggy execution paths from the model checker
+......................................................
-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
-under the model-checker. Event the output of the program is difficult to
-interpret. Moreover, the model-checker does not behave nicely with advanced
-debugging tools such as valgrind. For those reason, to identify a trajectory
-in the execution graph with the model-checker and replay this trajcetory and
-without the model-checker black-magic but with more standard tools
-(such as a debugger, valgrind, etc.). For this reason, Simgrid implements an
-experimental record/replay functionnality in order to record a trajectory with
-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. To enable this behavious the
-``model-check/record`` must be set to **yes**, which is not the case
-by default.
+Debugging the problems reported by the model checker is challenging: First, the
+application under verification cannot be debugged with gdb because the
+model checker already traces it. Then, the model checker may explore several
+execution paths before encountering the issue, making it very difficult to
+understand the outputs. Fortunately, SimGrid provides the execution path leading
+to any reported issue so that you can replay this path out of the model checker,
+enabling the usage of classical debugging tools.
-Here is an example of output:
+When the model checker finds an interesting path in the application
+execution graph (where a safety or liveness property is violated), it
+generates an identifier for this path. Here is an example of output:
.. code-block:: shell
[ 0.000000] (0:@) *** PROPERTY NOT VALID ***
[ 0.000000] (0:@) **************************
[ 0.000000] (0:@) Counter-example execution trace:
+ [ 0.000000] (0:@) [(1)Tremblay (app)] MC_RANDOM(3)
+ [ 0.000000] (0:@) [(1)Tremblay (app)] MC_RANDOM(4)
[ 0.000000] (0:@) Path = 1/3;1/4
- [ 0.000000] (0:@) [(1)Tremblay (app)] MC_RANDOM(3)
- [ 0.000000] (0:@) [(1)Tremblay (app)] MC_RANDOM(4)
[ 0.000000] (0:@) Expanded states = 27
[ 0.000000] (0:@) Visited states = 68
[ 0.000000] (0:@) Executed transitions = 46
-This path can then be replayed outside of the model-checker (and even
-in non-MC build of simgrid) by setting the ``model-check/replay`` item
-to the given path. The other options should be the same (but the
-model-checker should be disabled).
-
-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.
+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. 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
----------------------------------------
interrupted, and only gets released when the simulated clock reaches
the point where the blocking operation is done. This is explained
graphically in the `relevant tutorial, available online
-<http://simgrid.gforge.inria.fr/tutorials/simgrid-simix-101.pdf>`_.
+<https://simgrid.org/tutorials/simgrid-simix-101.pdf>`_.
In SimGrid, the containers in which user processes are virtualized are
called contexts. Several context factory are provided, and you can
raw implementation.
|br| Install the relevant library (e.g. with the
libboost-contexts-dev package on Debian/Ubuntu) and recompile
- SimGrid.
+ SimGrid.
- **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.
The main reason to change this setting is when the debugging tools get
fooled by the optimized context factories. Threads are the most
-debugging-friendly contextes, as they allow to set breakpoints
+debugging-friendly contexts, as they allow one to set breakpoints
anywhere with gdb and visualize backtraces for all processes, in order
to debug concurrency issues. Valgrind is also more comfortable with
threads, but it should be usable with all factories (Exception: the
If you want to push the scalability limits of your code, you might
want to reduce the ``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.
+as 16 KiB, for example. This *setting is ignored* when using the
+thread factory. Instead, you should compile SimGrid and your
+application with ``-fsplit-stack``. Note that this compilation flag is
+not compatible with the model checker right now.
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
**Option** ``contexts/guard-size`` **Default** 1 page in most case (0 pages on Windows or with MC)
-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 ``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 (with :ref:`contexts/stack-size
-<cfg=contexts/stack-size>`) as the stack will silently overflow on
-other parts of the memory.
+Unless you use the threads context factory (see
+:ref:`cfg=contexts/factory`), 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 ``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 (with
+:ref:`contexts/stack-size <cfg=contexts/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
on other parts of the memory if their size is too small for the
.. _cfg=contexts/nthreads:
.. _cfg=contexts/parallel-threshold:
.. _cfg=contexts/synchro:
-
+
Running User Code in Parallel
.............................
If you are using the **ucontext** or **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 ``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).
+launched, each of them handling the same number of user contexts at each
+run. To activate this, set the ``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
your machine for no good reason. You probably prefer the other less
eager schemas.
-
Configuring the Tracing
-----------------------
- SMPI simulator and traces for a space/time view:
.. code-block:: shell
-
+
smpirun -trace ...
The `-trace` parameter for the smpirun script runs the simulation
- Add the contents of a textual file on top of the trace file as comment:
.. code-block:: shell
-
+
--cfg=tracing/comment-file:my_file_with_additional_information.txt
Please, use these two parameters (for comments) to make reproducible
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 ``smpi/host-speed`` allows to specify
+simulated machine. The variable ``smpi/host-speed`` allows one 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.
application, the variable ``smpi/simulate-computation`` should be set
to no. 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
+doing that, you should check the SMPI_SAMPLE macros, documented in
Section :ref:`SMPI_adapting_speed`.
+------------------------------------+-------------------------+-----------------------------+
| Solution | Computations executed? | Computations simulated? |
-+====================================+=========================+=============================+
++====================================+=========================+=============================+
| --cfg=smpi/simulate-computation:no | Yes | Never |
+------------------------------------+-------------------------+-----------------------------+
| --cfg=smpi/cpu-threshold:42 | Yes, in all cases | If it lasts over 42 seconds |
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:
-
+
Reporting Simulation Time
.........................
increase the latency, i.e., values larger than or equal to 1 are valid here.
.. _cfg=smpi/papi-events:
-
+
Trace hardware counters with PAPI
.................................
files (See Section :ref:`tracing_tracing_options`).
.. warning::
-
+
This feature currently requires superuser privileges, as registers
are queried. Only use this feature with code you trust! Call
smpirun for instance via ``smpirun -wrapper "sudo "
possible to avoid this, as described in the main `SMPI publication
<https://hal.inria.fr/hal-01415484>`_ and in the :ref:`SMPI
documentation <SMPI_what_globals>`. SimGrid provides two ways of
-automatically privatizing the globals, and this option allows to
+automatically privatizing the globals, and this option allows one to
choose between them.
- **no** (default when not using smpirun): Do not automatically
use. Example:
.. code-block:: shell
-
+
ldd allpairf90
...
libgfortran.so.3 => /usr/lib/x86_64-linux-gnu/libgfortran.so.3 (0x00007fbb4d91b000)
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.
for each shared bloc.
With the ``global`` algorithm, each call to SMPI_SHARED_MALLOC()
-returns a new adress, but it only points to a shadow bloc: its memory
+returns a new address, 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.
At the end, no matter how many SMPI_SHARED_MALLOC you do, this will
Then, it can be deallocated by calling SMPI_SHARED_FREE(mem).
When smpi/shared-malloc:global is used, the memory consumption problem
-is solved, but it may induce too much load on the kernel's pages table.
+is solved, but it may induce too much load on the kernel's pages table.
In this case, you should use huge pages so that we create only one
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-block:: shell
-
+
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
to issue if your application contains such a loop:
.. code-block:: cpp
-
+
while(MPI_Wtime() < some_time_bound) {
/* some tests, with no communication nor computation */
}
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
