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 \b smpi/running-power allows to specify the
-computational power of the host machine (in flop/s) to use when
+machine. The variable \b smpi/host-speed allows 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.
seconds) below which the execution chunks are not reported to the
simulation kernel (default value: 1e-6).
-
\note
The option smpi/cpu-threshold ignores any computation time spent
below this threshold. SMPI does not consider the \a amount of these
value that is too low, you may end up with unreliable simulation
results.
- In some cases, however, one may wish to disable simulation of
+In some cases, however, one may wish to disable simulation of
application computation. This is the case when SMPI is used not to
simulate an MPI applications, but instead an MPI code that performs
"live replay" of another MPI app (e.g., ScalaTrace's replay tool,
To disable the benchmarking/simulation of computation in the simulated
application, the variable \b smpi/simulate-computation should be set to no.
-Equivalently, setting \b smpi/cpu-threshold to -1 also ignores all
-computation.
\note
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 the chapter
+ you should check the SMPI_SAMPLE macros, documented in the section
\ref SMPI_adapting_speed.
+Solution | Computations actually executed? | Computations simulated ?
+---------------------------------- | ------------------------------- | ------------------------
+--cfg=smpi/simulate-computation:no | Yes | No, never
+--cfg=smpi/cpu-threshold:42 | Yes, in all cases | Only if it lasts more than 42 seconds
+SMPI_SAMPLE() macro | Only once per loop nest (see @ref SMPI_adapting_speed "documentation") | Always
+
\subsection options_model_smpi_adj_file smpi/comp-adjustment-file: Slow-down or speed-up parts of your code.
This option allows you to pass a file that contains two columns: The first column
Internally, in order to speed up execution, we use a counter to keep track
on how often we already checked if the handle is now valid or not. Hence, we
actually use counter*SLEEP_TIME, that is, the time MPI_Test() causes the process
- to sleep increases linearly with the number of previously failed testk.
+ to sleep increases linearly with the number of previously failed tests. This
+ behavior can be disabled by setting smpi/grow-injected-times to no. This will
+ also disable this behavior for MPI_Iprobe.
\subsection options_model_smpi_use_shared_malloc smpi/use-shared-malloc: Factorize malloc()s
- \c smpi/comp-adjustment-file: \ref options_model_smpi_adj_file
- \c smpi/cpu-threshold: \ref options_smpi_bench
- \c smpi/display-timing: \ref options_smpi_timing
-- \c smpi/lat-factor: \ref options_model_smpi_lat_factor
+- \c smpi/grow-injected-times: \ref options_model_smpi_test
+- \c smpi/host-speed: \ref options_smpi_bench
- \c smpi/IB-penalty-factors: \ref options_model_network_coefs
- \c smpi/iprobe: \ref options_model_smpi_iprobe
- \c smpi/init: \ref options_model_smpi_init
+- \c smpi/lat-factor: \ref options_model_smpi_lat_factor
- \c smpi/ois: \ref options_model_smpi_ois
- \c smpi/or: \ref options_model_smpi_or
- \c smpi/os: \ref options_model_smpi_os
- \c smpi/papi-events: \ref options_smpi_papi_events
- \c smpi/privatize-global-variables: \ref options_smpi_global
-- \c smpi/running-power: \ref options_smpi_bench
- \c smpi/send-is-detached-thresh: \ref options_model_smpi_detached
- \c smpi/simulate-computation: \ref options_smpi_bench
- \c smpi/test: \ref options_model_smpi_test
