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@@ -572,15 +572,37 @@ $ starpu_paje_sort paje.trace
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\section PapiCounters PAPI counters
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-Performance counter values can be obtained from the PAPI framework if
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+Performance counter values could be obtained from the PAPI framework if
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<c>./configure</c> detected the libpapi. One has to set the \ref STARPU_PROFILING
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-environment variable to 1 and then specify which counters to record with the
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+environment variable to 1 and then specify which events to record with the
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\ref STARPU_PROF_PAPI_EVENTS environment variable. For instance:
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\verbatim
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export STARPU_PROFILING=1 STARPU_PROF_PAPI_EVENTS="PAPI_TOT_INS PAPI_TOT_CYC"
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\endverbatim
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+In the current simple implementation, only CPU tasks have their events measured
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+and require CPUs that support the PAPI events. All events that PAPI support are
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+available from their documentation (https://icl.cs.utk.edu/projects/papi/wiki/PAPIC:Preset_Event_Definitions).
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+It is important to note that not all events are available on all systems, and
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+general PAPI recommendations should be followed.
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+
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+The counter values can be accessed using the profiling interface:
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+\code{.c}
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+task->profiling_info->papi_values
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+\endcode
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+Also, it can be accessed and/or saved with tracing when using \ref STARPU_FXT_TRACE. With the use of <c>starpu_fxt_tool</c>
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+the file <c>papi.rec</c> is generated containing the following triple:
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+
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+\verbatim
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+Task Id
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+Event Id
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+Value
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+\endverbatim
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+
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+External tools like <c>rec2csv</c> can be used to convert this rec file to a <c>csv</c>, where each
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+line represents a value for an event for a task.
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+
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\section TheoreticalLowerBoundOnExecutionTime Theoretical Lower Bound On Execution Time
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StarPU can record a trace of what tasks are needed to complete the
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Lucas Nesi