-Denable_model-checking .``) and then compile SimGrid :ref:`as usual <install_src>`. Unfortunately, Mc SimGrid does not work natively
on Mac OS X yet, so mac users should stick to the docker method for now.
-.. code-block:: shell
+.. code-block:: console
- docker image pull simgrid/tuto-mc
- mkdir ~/tuto-mcsimgrid # or chose another directory to share between your computer and the docker container
- docker run -it --rm --name mcsimgrid --volume ~/tuto-mcsimgrid:/source/tutorial simgrid/tuto-mc bash
+ $ docker image pull simgrid/tuto-mc
+ $ mkdir ~/tuto-mcsimgrid # or chose another directory to share between your computer and the docker container
+ $ docker run -it --rm --name mcsimgrid --volume ~/tuto-mcsimgrid:/source/tutorial simgrid/tuto-mc bash
In the container, you have access to the following directories of interest:
Let's go with a first example of a bugged program. Once in the container, copy all files from the tutorial into the directory shared
between your host computer and the container.
-.. code-block:: shell
+.. code-block:: console
# From within the container
$ cp -r /source/tuto-mc.git/* /source/tutorial/
send their parameter to a given mailbox. A ``server`` receives 3 messages and assumes that the last received message is the number ``3``.
If you compile and run it, it simply works:
-.. code-block:: shell
+.. code-block:: console
$ cmake . && make
(output omitted)
source code and/or the platform file, but this is not a method. Time to start Mc SimGrid, the SimGrid model checker, to exhaustively test
all message orders. For that, you simply launch your simulation as a parameter to the ``simgrid-mc`` binary as you would do with ``valgrind``:
-.. code-block:: shell
+.. code-block:: console
$ simgrid-mc ./ndet-receive-s4u small_platform.xml
(some output ignored)
all possible outcome of the code, the execution is sometimes rewind to explore another possible branch (here: another possible
message ordering). Note also that all times are always 0 in the model checker, since the time is abstracted away in this mode.
- .. code-block:: shell
+ .. code-block:: console
[0.000000] [mc_safety/INFO] Check a safety property. Reduction is: dpor.
[Jupiter:client:(2) 0.000000] [example/INFO] Sending 1
- Then you have the error message, along with a backtrace of the application at the point where the assertion fails. Not all the frames of
the backtrace are useful, and some are omitted here.
- .. code-block:: shell
+ .. code-block:: console
[Tremblay:server:(1) 0.000000] /source/tutorial/ndet-receive-s4u.cpp:27: [root/CRITICAL] Assertion value_got == 3 failed
Backtrace (displayed in actor server):
- First, the error message itself. The ``xbt_assert`` in the code result in an ``abort()`` in the application, that is interpreted as an
application crash by the model-checker.
- .. code-block:: shell
+ .. code-block:: console
[0.000000] [mc_ModelChecker/INFO] **************************
[0.000000] [mc_ModelChecker/INFO] ** CRASH IN THE PROGRAM **
calls we made (put/get) are split in atomic calls (iSend+Wait/iRecv+Wait), and all executions are interleaved. Also, Mc SimGrid
reports the first faulty execution it finds: it may not be the shorter possible one.
- .. code-block:: shell
+ .. code-block:: console
[0.000000] [mc_ModelChecker/INFO] Counter-example execution trace:
[0.000000] [mc_ModelChecker/INFO] [(1)Tremblay (server)] iRecv(dst=(1)Tremblay (server), buff=(verbose only), size=(verbose only))
- Then, the execution path is given.
- .. code-block:: shell
+ .. code-block:: console
[0.000000] [mc_record/INFO] Path = 1;2;1;1;2;4;1;1;3;1
without ``simgrid-mc``. This is because ``simgrid-mc`` forbids to use a debugger such as gdb or valgrind on the code during the
model-checking. For example, you can trigger the same execution in valgrind as follows:
- .. code-block:: shell
+ .. code-block:: console
$ valgrind ./ndet-receive-s4u small_platform.xml --cfg=model-check/replay:'1;2;1;1;2;4;1;1;3;1'
==402== Memcheck, a memory error detector
point of the exploration), the visited states (the amount of times we visited another state -- the same state may have been visited
several times) and the amount of transitions.
- .. code-block:: shell
+ .. code-block:: console
[0.000000] [mc_safety/INFO] Expanded states = 22
[0.000000] [mc_safety/INFO] Visited states = 56
|br|
You can compile and run it on top of SimGrid as follows.
-.. code-block:: shell
+.. code-block:: console
$ smpicc ndet-receive-mpi.c -o ndet-receive-mpi
$ smpirun -np 4 -platform small_platform.xml ndet-receive-mpi
leading to it. It may not be the case on your machine, as this depends on the iteration order of an unsorted collection. Instead, we
should use Mc SimGrid to exhaustively explore the state space and trigger the bug in all cases.
-.. code-block:: shell
+.. code-block:: console
$ smpirun -wrapper simgrid-mc -np 4 -platform small_platform.xml ndet-receive-mpi
The produced output is then very similar to the one you get with S4U, even if the exact execution path leading to the bug may differs. You
can also trigger a given execution path out of the model-checker, for example to explore it with valgrind.
-.. code-block:: shell
+.. code-block:: console
$ smpirun -wrapper valgrind -np 4 -platform small_platform.xml --cfg=model-check/replay:'1;2;1;1;4;1;1;3;1' ndet-receive-mpi
