[PATCH] perf test: Fix parse-events tests to skip parametrized events

[Ian Rogers]

On Sun, Aug 6, 2023 at 9:50 PM Athira Rajeev
<atrajeev at linux.vnet.ibm.com> wrote:
>
> Testcase "Parsing of all PMU events from sysfs" parse events for
> all PMUs, and not just cpu. In case of powerpc, the PowerVM
> environment supports events from hv_24x7 and hv_gpci PMU which
> is of example format like below:
>
> - hv_24x7/CPM_ADJUNCT_INST,domain=?,core=?/
> - hv_gpci/event,partition_id=?/
>
> The value for "?" needs to be filled in depending on system
> configuration. It is better to skip these parametrized events
> in this test as it is done in:
> 'commit b50d691e50e6 ("perf test: Fix "all PMU test" to skip
> parametrized events")' which handled a simialr instance with
> "all PMU test".

I'd say this is different, the "?" is really ugly. On other
architectures the problem is solved by having >1 PMU, domain and core
can be meta-data associated with the PMU. If we want to aggregate
based on domain and core in the perf tool, it will need a different
way of solving the problem for Power. Skipping the test is just
pushing this problem down the road.

> Fix parse-events test to skip parametrized events since
> it needs proper setup of the parameters.
>
> Signed-off-by: Athira Rajeev <atrajeev at linux.vnet.ibm.com>
> ---
>  tools/perf/tests/parse-events.c | 32 ++++++++++++++++++++++++++++++++
>  1 file changed, 32 insertions(+)
>
> diff --git a/tools/perf/tests/parse-events.c b/tools/perf/tests/parse-events.c
> index b2f82847e4c3..605373c7d005 100644
> --- a/tools/perf/tests/parse-events.c
> +++ b/tools/perf/tests/parse-events.c
> @@ -2504,7 +2504,11 @@ static int test__pmu_events(struct test_suite *test __maybe_unused, int subtest
>         while ((pmu = perf_pmus__scan(pmu)) != NULL) {
>                 struct stat st;
>                 char path[PATH_MAX];
> +               char pmu_event[PATH_MAX + 256];

By definition paths can't be longer than PATH_MAX.

> +               char *buf = NULL;
> +               FILE *file;
>                 struct dirent *ent;
> +               size_t len = 0;
>                 DIR *dir;
>                 int err;
>
> @@ -2528,11 +2532,39 @@ static int test__pmu_events(struct test_suite *test __maybe_unused, int subtest
>                         struct evlist_test e = { .name = NULL, };
>                         char name[2 * NAME_MAX + 1 + 12 + 3];
>                         int test_ret;
> +                       int skip = 0;

Prefer a boolean. Prefer is_event_parameterized over skip to make
variable name more intention revealing.

>
>                         /* Names containing . are special and cannot be used directly */
>                         if (strchr(ent->d_name, '.'))
>                                 continue;
>
> +                       /* exclude parametrized ones (name contains '?') */
> +                       snprintf(pmu_event, PATH_MAX + 256, "%s%s", path, ent->d_name);

Use sizeof(pmu_event) rather than "PATH_MAX + 256".

Thanks,
Ian

> +                       file = fopen(pmu_event, "r");
> +                       if (!file) {
> +                               pr_debug("can't open pmu event file for '%s'\n", ent->d_name);
> +                               ret = combine_test_results(ret, TEST_FAIL);
> +                               continue;
> +                       }
> +
> +                       if (getline(&buf, &len, file) < 0) {
> +                               pr_debug(" pmu event: %s is a null event\n", ent->d_name);
> +                               ret = combine_test_results(ret, TEST_FAIL);
> +                               continue;
> +                       }
> +
> +                       if (strchr(buf, '?'))
> +                               skip = 1;
> +
> +                       free(buf);
> +                       buf = NULL;
> +                       fclose(file);
> +
> +                       if (skip == 1) {
> +                               pr_debug("skipping parametrized PMU event: %s which contains ?\n", pmu_event);
> +                               continue;
> +                       }
> +
>                         snprintf(name, sizeof(name), "%s/event=%s/u", pmu->name, ent->d_name);
>
>                         e.name  = name;
> --
> 2.31.1
>