Commit a7cacaa0 authored by Madadi Vineeth Reddy's avatar Madadi Vineeth Reddy Committed by Namhyung Kim
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perf sched replay: Fix -r/--repeat command line option for infinity 



Currently, the -r/--repeat option accepts values from 0 and complains
for -1. The help section specifies:
-r, --repeat <n>      repeat the workload replay N times (-1: infinite)

The -r -1 option raises an error because replay_repeat is defined as
an unsigned int.

In the current implementation, the workload is repeated n times when
-r <n> is used, except when n is 0.

When -r is set to 0, the workload is also repeated once. This happens
because when -r=0, the run_one_test function is not called. (Note that
mutex unlocking, which is essential for child threads spawned to emulate
the workload, happens in run_one_test.) However, mutex unlocking is
still performed in the destroy_tasks function. Thus, -r=0 results in the
workload running once coincidentally.

To clarify and maintain the existing logic for -r >= 1 (which runs the
workload the specified number of times) and to fix the issue with infinite
runs, make -r=0 perform an infinite run.

Reviewed-by: default avatarJames Clark <james.clark@arm.com>
Signed-off-by: default avatarMadadi Vineeth Reddy <vineethr@linux.ibm.com>
Cc: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Link: https://lore.kernel.org/r/20240628071821.15264-1-vineethr@linux.ibm.com


Signed-off-by: default avatarNamhyung Kim <namhyung@kernel.org>
parent 5484fd27

tools/perf/Documentation/perf-sched.txt

+7 −0
Original line number Diff line number Diff line
@@ -202,6 +202,13 @@ OPTIONS for 'perf sched timehist' 
--state::

	Show task state when it switched out.



OPTIONS for 'perf sched replay'

------------------------------



-r::

--repeat <n>::

	repeat the workload n times (0: infinite). Default is 10.



SEE ALSO

--------

linkperf:perf-record[1]

tools/perf/builtin-sched.c

+4 −1
Original line number Diff line number Diff line
@@ -3386,6 +3386,9 @@ static int perf_sched__replay(struct perf_sched *sched) 
	sched->thread_funcs_exit = false;

	create_tasks(sched);

	printf("------------------------------------------------------------\n");

	if (sched->replay_repeat == 0)

		sched->replay_repeat = UINT_MAX;



	for (i = 0; i < sched->replay_repeat; i++)

		run_one_test(sched);
@@ -3551,7 +3554,7 @@ int cmd_sched(int argc, const char **argv) 
	};

	const struct option replay_options[] = {

	OPT_UINTEGER('r', "repeat", &sched.replay_repeat,

		     "repeat the workload replay N times (-1: infinite)"),

		     "repeat the workload replay N times (0: infinite)"),

	OPT_PARENT(sched_options)

	};

	const struct option map_options[] = {