perf test: Avoid sysfs state affecting fake events

Icelake has a slots event, on my Skylakex I have CPU events in sysfs of
topdown-slots-issued and topdown-total-slots.

Legacy event parsing would try to use '-' to separate parts of an event
and so perf_pmu__parse_init sets 'slots' to be a
PMU_EVENT_SYMBOL_SUFFIX2.

As such parsing the slots event for a fake PMU fails as a
PMU_EVENT_SYMBOL_SUFFIX2 isn't made into the PE_PMU_EVENT_FAKE token.

Resolve this issue by test initializing the PMU parsing state before
every parse. This must be done every parse as the state is removes after
each parse_events.

Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexandre Torgue <alexandre.torgue@foss.st.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Caleb Biggers <caleb.biggers@intel.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Garry <john.garry@huawei.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Kshipra Bopardikar <kshipra.bopardikar@intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Perry Taylor <perry.taylor@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sedat Dilek <sedat.dilek@gmail.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Xing Zhengjun <zhengjun.xing@linux.intel.com>
Link: http://lore.kernel.org/lkml/20220725223633.2301737-2-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/tests/pmu-events.c

@@ -812,6 +812,15 @@ static int check_parse_id(const char *id, struct parse_events_error *error,
 	for (cur = strchr(dup, '@') ; cur; cur = strchr(++cur, '@'))
 		*cur = '/';
 
+	if (fake_pmu) {
+		/*
+		 * Every call to __parse_events will try to initialize the PMU
+		 * state from sysfs and then clean it up at the end. Reset the
+		 * PMU events to the test state so that we don't pick up
+		 * erroneous prefixes and suffixes.
+		 */
+		perf_pmu__test_parse_init();
+	}
 	ret = __parse_events(evlist, dup, error, fake_pmu);
 	free(dup);