Messages in this thread | | | Date | Thu, 13 Oct 2022 13:11:00 +0100 | Subject | Re: [PATCH v1] perf test: Parse events workaround for dash/minus | From | John Garry <> |
| |
On 13/10/2022 02:12, Ian Rogers wrote: > Skip an event configuration for event names with a dash/minus in them. > Events with a dash/minus in their name cause parsing issues as legacy > encoding of events would use a dash/minus as a separator. The parser > separates events with dashes into prefixes and suffixes and then > recombines them. Unfortunately if an event has part of its name that > matches a legacy token then the recombining fails. This is seen for > branch-brs where branch is a legacy token. branch-brs was introduced > to sysfs in: > https://lore.kernel.org/all/20220322221517.2510440-5-eranian@google.com/ > The failure is shown below as well as the workaround to use a config > where the dash/minus isn't treated specially: > > ``` > $ perf stat -e branch-brs true > event syntax error: 'branch-brs' > \___ parser error > > $ perf stat -e cpu/branch-brs/ true > > Performance counter stats for 'true': > > 46,179 cpu/branch-brs/ > ``` > > Signed-off-by: Ian Rogers <irogers@google.com> > --- > tools/perf/tests/parse-events.c | 13 +++++++++++++ > 1 file changed, 13 insertions(+) > > diff --git a/tools/perf/tests/parse-events.c b/tools/perf/tests/parse-events.c > index 459afdb256a1..3440dd2616b0 100644 > --- a/tools/perf/tests/parse-events.c > +++ b/tools/perf/tests/parse-events.c > @@ -2237,6 +2237,19 @@ static int test__pmu_events(struct test_suite *test __maybe_unused, int subtest > pr_debug("Test PMU event failed for '%s'", name); > ret = combine_test_results(ret, test_ret); >
Hi Ian,
} > + /* > + * Names containing '-' are recognized as prefixes and suffixes > + * due to '-' being a legacy PMU separator. This fails when the > + * prefix or suffix collides with an existing legacy token. For > + * example, branch-brs has a prefix (branch) that collides with > + * a PE_NAME_CACHE_TYPE token causing a parse error as a suffix > + * isn't expected after this.
OK, so you want to skip anything with '-'. Will we now miss out on events which contain a '-' but don't clash with an existing legacy token?
> As event names in the config > + * slashes are allowed a '-' in the name we check this works > + * above.
Sorry, I can't follow what you mean here. Do you mean that "cpu/branch-brs/" works ok and we continue to test it?
> + */ > + if (strchr(ent->d_name, '-')) > + continue;
Thanks, John
> + > snprintf(name, sizeof(name), "%s:u,cpu/event=%s/u", ent->d_name, ent->d_name); > e.name = name; > e.check = test__checkevent_pmu_events_mix;
| |