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perf test: Parse events workaround for dash/minus 

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>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Garry <john.garry@huawei.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lore.kernel.org/lkml/20221013011205.3151391-1-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Ian Rogers 2022-10-12 18:12:05 -07:00 committed by Arnaldo Carvalho de Melo
parent 2e5a738abc
commit 146edff3d7
1 changed files with 13 additions and 0 deletions
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13
tools/perf/tests/parse-events.c
View File

@ -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);
}
/*
* 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. As event names in the config
* slashes are allowed a '-' in the name we check this works
* above.
*/
if (strchr(ent->d_name, '-'))
continue;
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;