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>

1 files changed, 13 insertions, 0 deletions

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);
 		}
+		/*
+		 * 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;