- **surf/precision:** :ref:`cfg=surf/precision`
- **For collective operations of SMPI,** please refer to Section :ref:`cfg=smpi/coll-selector`
+- **smpi/auto-shared-malloc-thresh:** :ref:`cfg=smpi/auto-shared-malloc-thresh`
- **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`
- **smpi/cpu-threshold:** :ref:`cfg=smpi/cpu-threshold`
+- **smpi/display-allocs:** :ref:`cfg=smpi/display-allocs`
- **smpi/display-timing:** :ref:`cfg=smpi/display-timing`
- **smpi/grow-injected-times:** :ref:`cfg=smpi/grow-injected-times`
- **smpi/host-speed:** :ref:`cfg=smpi/host-speed`
https://simgrid.org/contrib/smpi-saturation-doc.html
.. _cfg=smpi/display-timing:
-
Reporting Simulation Time
.........................
simulation ends. If you enable the ``smpi/display-timing`` item,
``smpirun`` will display this information when the simulation
ends.
+SMPI will also display information about the amout of real time spent
+in application code and in SMPI internals, to provide hints about the
+need to use sampling to reduce simulation time.
+
+.. _cfg=smpi/display-allocs:
+Reporting memory allocations
+.........................
+
+**Option** ``smpi/display-allocs`` **Default:** 0 (false)
+
+SMPI intercepts malloc and calloc calls performed inside the running
+application, if it wasn't compiled with SMPI_NO_OVERRIDE_MALLOC.
+With this option, SMPI will show at the end of execution the amount of
+memory allocated through these calls, and locate the most expensive one.
+This helps finding the targets for manual memory sharing, or the threshold
+to use for smpi/auto-shared-malloc-thresh option (see :ref:`cfg=smpi/auto-shared-malloc-thresh`).
.. _cfg=smpi/keep-temps:
``--cfg=smpi/shared-malloc-hugepage:/home/huge`` to smpirun to
actually activate the huge page support in shared mallocs.
+.. _cfg=smpi/auto-shared-malloc-thresh:
+Automatically share allocations
+.........................
+
+**Option** ``smpi/auto-shared-malloc-thresh:`` **Default:** 0 (false)
+ This value in bytes represents the size above which all allocations
+ will be "shared" by default (as if they were performed through
+ SMPI_SHARED_MALLOC macros). Default = 0 = disabled feature.
+ The value must be carefully chosen to only select data buffers which
+ will not modify execution path or cause crash if their content is false.
+ Option :ref:`cfg=smpi/display-allocs` can be used to locate the largest
+ allocation detected in a run, and provide a good starting threshold.
+ Note : malloc, calloc and free are overridden by smpicc/cxx by default.
+ This can cause some troubles if codes are already overriding these. If this
+ is the case, defining SMPI_NO_OVERRIDE_MALLOC in the compilation flags can
+ help, but will make this feature unusable.
+
.. _cfg=smpi/wtime:
Inject constant times for MPI_Wtime, gettimeofday and clock_gettime
