Re: [PATCH v2 3/3] perf test: Add a runs-per-test flag

[Namhyung Kim <namhyung@kernel.org>]

On Tue, Jan 07, 2025 at 02:01:52PM -0800, Ian Rogers wrote:
> To detect flakes it is useful to run tests more than once. Add a
> runs-per-test flag that will run each test multiple times.

Does it change the output?  What if it sometimes succeeds and fails?
It'd be nice if you can add an example output in the commit log.

Also please update the documentation.

Thanks,
Namhyung

> 
> Signed-off-by: Ian Rogers <irogers@google.com>
> ---
>  tools/perf/tests/builtin-test.c | 28 +++++++++++++++++-----------
>  1 file changed, 17 insertions(+), 11 deletions(-)
> 
> diff --git a/tools/perf/tests/builtin-test.c b/tools/perf/tests/builtin-test.c
> index 887f735da900..729740c1e5e5 100644
> --- a/tools/perf/tests/builtin-test.c
> +++ b/tools/perf/tests/builtin-test.c
> @@ -42,6 +42,8 @@
>  static bool dont_fork;
>  /* Fork the tests in parallel and wait for their completion. */
>  static bool sequential;
> +/* Number of times each test is run. */
> +static unsigned int runs_per_test = 1;
>  const char *dso_to_test;
>  const char *test_objdump_path = "objdump";
>  
> @@ -485,7 +487,7 @@ static int __cmd_test(struct test_suite **suites, int argc, const char *argv[],
>  			len = strlen(test_description(*t, i));
>  			if (width < len)
>  				width = len;
> -			num_tests++;
> +			num_tests += runs_per_test;
>  		}
>  	}
>  	child_tests = calloc(num_tests, sizeof(*child_tests));
> @@ -549,16 +551,18 @@ static int __cmd_test(struct test_suite **suites, int argc, const char *argv[],
>  				continue;
>  			}
>  
> -			test_suite__for_each_test_case(*t, curr_test_case) {
> -				if (!perf_test__matches(test_description(*t, curr_test_case),
> -							curr_suite, argc, argv))
> -					continue;
> -
> -				err = start_test(*t, curr_suite, curr_test_case,
> -						 &child_tests[child_test_num++],
> -						 width, pass);
> -				if (err)
> -					goto err_out;
> +			for (unsigned int run = 0; run < runs_per_test; run++) {
> +				test_suite__for_each_test_case(*t, curr_test_case) {
> +					if (!perf_test__matches(test_description(*t, curr_test_case),
> +								curr_suite, argc, argv))
> +						continue;
> +
> +					err = start_test(*t, curr_suite, curr_test_case,
> +							 &child_tests[child_test_num++],
> +							 width, pass);
> +					if (err)
> +						goto err_out;
> +				}
>  			}
>  		}
>  		if (!sequential) {
> @@ -698,6 +702,8 @@ int cmd_test(int argc, const char **argv)
>  		    "Do not fork for testcase"),
>  	OPT_BOOLEAN('S', "sequential", &sequential,
>  		    "Run the tests one after another rather than in parallel"),
> +	OPT_UINTEGER('r', "runs-per-test", &runs_per_test,
> +		     "Run each test the given number of times, default 1"),
>  	OPT_STRING('w', "workload", &workload, "work", "workload to run for testing, use '--list-workloads' to list the available ones."),
>  	OPT_BOOLEAN(0, "list-workloads", &list_workloads, "List the available builtin workloads to use with -w/--workload"),
>  	OPT_STRING(0, "dso", &dso_to_test, "dso", "dso to test"),
> -- 
> 2.47.1.613.gc27f4b7a9f-goog
>