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Date: Tue, 18 Jun 2024 11:59:26 +0100
From: James Clark <james.clark@....com>
To: Ian Rogers <irogers@...gle.com>
Cc: linux-perf-users <linux-perf-users@...r.kernel.org>,
Robin Murphy <robin.murphy@....com>, Peter Zijlstra <peterz@...radead.org>,
Ingo Molnar <mingo@...hat.com>, Arnaldo Carvalho de Melo <acme@...nel.org>,
Namhyung Kim <namhyung@...nel.org>, Mark Rutland <mark.rutland@....com>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
Jiri Olsa <jolsa@...nel.org>, Adrian Hunter <adrian.hunter@...el.com>,
"Liang, Kan" <kan.liang@...ux.intel.com>, LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/2] perf pmu: Restore full PMU name wildcard support
On 17/06/2024 22:25, Ian Rogers wrote:
> On Mon, Jun 17, 2024, 6:44 AM James Clark <james.clark@....com> wrote:
>
>> Commit b2b9d3a3f021 ("perf pmu: Support wildcards on pmu name in dynamic
>> pmu events") gives the following example for wildcarding a subset of
>> PMUs:
>>
>> E.g., in a system with the following dynamic pmus:
>>
>> mypmu_0
>> mypmu_1
>> mypmu_2
>> mypmu_4
>>
>> perf stat -e mypmu_[01]/<config>/
>>
>> Since commit f91fa2ae6360 ("perf pmu: Refactor perf_pmu__match()"), only
>> "*" has been supported, removing the ability to subset PMUs, even though
>> parse-events.l still supports ? and [] characters.
>>
>> Fix it by using fnmatch() when any glob character is detected and add a
>> test which covers that and other scenarios of
>> perf_pmu__match_ignoring_suffix().
>>
>> Fixes: f91fa2ae6360 ("perf pmu: Refactor perf_pmu__match()")
>> Signed-off-by: James Clark <james.clark@....com>
>>
>
> We use regular expression matching elsewhere rather than fnmatch. We can
> also precompile the matchers using lex. I'm not sure we shouldn't be
> looking for an opportunity to remove fnmatch rather than expand upon it.
>
> Thanks,
> Ian
>
Presumably you mean we can do the removal of fnmatch after this fix goes in,
rather than instead of? Because this is a user facing change in behaviour
but the removal of fnmatch would be an non-user facing code refactor?
It's technically not an "expansion" because we always used fnmatch and the
linked commit hasn't made it to a release yet.
>
> ---
>> tools/perf/tests/pmu.c | 78 ++++++++++++++++++++++++++++++++++++++++++
>> tools/perf/util/pmu.c | 2 +-
>> 2 files changed, 79 insertions(+), 1 deletion(-)
>>
>> diff --git a/tools/perf/tests/pmu.c b/tools/perf/tests/pmu.c
>> index cc88b5920c3e..fd07331b2d6e 100644
>> --- a/tools/perf/tests/pmu.c
>> +++ b/tools/perf/tests/pmu.c
>> @@ -437,12 +437,90 @@ static int test__name_cmp(struct test_suite *test
>> __maybe_unused, int subtest __
>> return TEST_OK;
>> }
>>
>> +/**
>> + * Test perf_pmu__match() that's used to search for a PMU given a name
>> passed
>> + * on the command line. The name that's passed may also be a filename
>> type glob
>> + * match.
>> + */
>> +static int test__pmu_match(struct test_suite *test __maybe_unused, int
>> subtest __maybe_unused)
>> +{
>> + struct perf_pmu test_pmu;
>> +
>> + test_pmu.name = "pmuname";
>> + TEST_ASSERT_EQUAL("Exact match", perf_pmu__match(&test_pmu,
>> "pmuname"), true);
>> + TEST_ASSERT_EQUAL("Longer token", perf_pmu__match(&test_pmu,
>> "longertoken"), false);
>> + TEST_ASSERT_EQUAL("Shorter token", perf_pmu__match(&test_pmu,
>> "pmu"), false);
>> +
>> + test_pmu.name = "pmuname_10";
>> + TEST_ASSERT_EQUAL("Diff suffix_", perf_pmu__match(&test_pmu,
>> "pmuname_2"), false);
>> + TEST_ASSERT_EQUAL("Sub suffix_", perf_pmu__match(&test_pmu,
>> "pmuname_1"), true);
>> + TEST_ASSERT_EQUAL("Same suffix_", perf_pmu__match(&test_pmu,
>> "pmuname_10"), true);
>> + TEST_ASSERT_EQUAL("No suffix_", perf_pmu__match(&test_pmu,
>> "pmuname"), true);
>> + TEST_ASSERT_EQUAL("Underscore_", perf_pmu__match(&test_pmu,
>> "pmuname_"), true);
>> + TEST_ASSERT_EQUAL("Substring_", perf_pmu__match(&test_pmu,
>> "pmuna"), false);
>> +
>> + test_pmu.name = "pmuname_ab23";
>> + TEST_ASSERT_EQUAL("Diff suffix hex_", perf_pmu__match(&test_pmu,
>> "pmuname_2"), false);
>> + TEST_ASSERT_EQUAL("Sub suffix hex_", perf_pmu__match(&test_pmu,
>> "pmuname_ab"), true);
>> + TEST_ASSERT_EQUAL("Same suffix hex_", perf_pmu__match(&test_pmu,
>> "pmuname_ab23"), true);
>> + TEST_ASSERT_EQUAL("No suffix hex_", perf_pmu__match(&test_pmu,
>> "pmuname"), true);
>> + TEST_ASSERT_EQUAL("Underscore hex_", perf_pmu__match(&test_pmu,
>> "pmuname_"), true);
>> + TEST_ASSERT_EQUAL("Substring hex_", perf_pmu__match(&test_pmu,
>> "pmuna"), false);
>> +
>> + test_pmu.name = "pmuname10";
>> + TEST_ASSERT_EQUAL("Diff suffix", perf_pmu__match(&test_pmu,
>> "pmuname2"), false);
>> + TEST_ASSERT_EQUAL("Sub suffix", perf_pmu__match(&test_pmu,
>> "pmuname1"), true);
>> + TEST_ASSERT_EQUAL("Same suffix", perf_pmu__match(&test_pmu,
>> "pmuname10"), true);
>> + TEST_ASSERT_EQUAL("No suffix", perf_pmu__match(&test_pmu,
>> "pmuname"), true);
>> + TEST_ASSERT_EQUAL("Underscore", perf_pmu__match(&test_pmu,
>> "pmuname_"), false);
>> + TEST_ASSERT_EQUAL("Substring", perf_pmu__match(&test_pmu,
>> "pmuna"), false);
>> +
>> + test_pmu.name = "pmunameab23";
>> + TEST_ASSERT_EQUAL("Diff suffix hex", perf_pmu__match(&test_pmu,
>> "pmuname2"), false);
>> + TEST_ASSERT_EQUAL("Sub suffix hex", perf_pmu__match(&test_pmu,
>> "pmunameab"), true);
>> + TEST_ASSERT_EQUAL("Same suffix hex", perf_pmu__match(&test_pmu,
>> "pmunameab23"), true);
>> + TEST_ASSERT_EQUAL("No suffix hex", perf_pmu__match(&test_pmu,
>> "pmuname"), true);
>> + TEST_ASSERT_EQUAL("Underscore hex", perf_pmu__match(&test_pmu,
>> "pmuname_"), false);
>> + TEST_ASSERT_EQUAL("Substring hex", perf_pmu__match(&test_pmu,
>> "pmuna"), false);
>> +
>> + /*
>> + * 2 hex chars or less are not considered suffixes so it shouldn't
>> be
>> + * possible to wildcard by skipping the suffix. Therefore there
>> are more
>> + * false results here than above.
>> + */
>> + test_pmu.name = "pmuname_a3";
>> + TEST_ASSERT_EQUAL("Diff suffix 2 hex_", perf_pmu__match(&test_pmu,
>> "pmuname_2"), false);
>> + /*
>> + * This one should be false, but because pmuname_a3 ends in 3
>> which is
>> + * decimal, it's not possible to determine if it's a short hex
>> suffix or
>> + * a normal decimal suffix following text. And we want to match on
>> any
>> + * length of decimal suffix. Run the test anyway and expect the
>> wrong
>> + * result. And slightly fuzzy matching shouldn't do too much harm.
>> + */
>> + TEST_ASSERT_EQUAL("Sub suffix 2 hex_", perf_pmu__match(&test_pmu,
>> "pmuname_a"), true);
>> + TEST_ASSERT_EQUAL("Same suffix 2 hex_", perf_pmu__match(&test_pmu,
>> "pmuname_a3"), true);
>> + TEST_ASSERT_EQUAL("No suffix 2 hex_", perf_pmu__match(&test_pmu,
>> "pmuname"), false);
>> + TEST_ASSERT_EQUAL("Underscore 2 hex_", perf_pmu__match(&test_pmu,
>> "pmuname_"), false);
>> + TEST_ASSERT_EQUAL("Substring 2 hex_", perf_pmu__match(&test_pmu,
>> "pmuna"), false);
>> +
>> + test_pmu.name = "pmuname_5";
>> + TEST_ASSERT_EQUAL("Glob 1", perf_pmu__match(&test_pmu, "pmu*"),
>> true);
>> + TEST_ASSERT_EQUAL("Glob 2", perf_pmu__match(&test_pmu,
>> "nomatch*"), false);
>> + TEST_ASSERT_EQUAL("Seq 1", perf_pmu__match(&test_pmu,
>> "pmuname_[12345]"), true);
>> + TEST_ASSERT_EQUAL("Seq 2", perf_pmu__match(&test_pmu,
>> "pmuname_[67890]"), false);
>> + TEST_ASSERT_EQUAL("? 1", perf_pmu__match(&test_pmu,
>> "pmuname_?"), true);
>> + TEST_ASSERT_EQUAL("? 2", perf_pmu__match(&test_pmu,
>> "pmuname_1?"), false);
>> +
>> + return TEST_OK;
>> +}
>> +
>> static struct test_case tests__pmu[] = {
>> TEST_CASE("Parsing with PMU format directory", pmu_format),
>> TEST_CASE("Parsing with PMU event", pmu_events),
>> TEST_CASE("PMU event names", pmu_event_names),
>> TEST_CASE("PMU name combining", name_len),
>> TEST_CASE("PMU name comparison", name_cmp),
>> + TEST_CASE("PMU cmdline match", pmu_match),
>> { .name = NULL, }
>> };
>>
>> diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
>> index c94a91645b21..97d74fe6d816 100644
>> --- a/tools/perf/util/pmu.c
>> +++ b/tools/perf/util/pmu.c
>> @@ -2150,7 +2150,7 @@ void perf_pmu__warn_invalid_config(struct perf_pmu
>> *pmu, __u64 config,
>> bool perf_pmu__match(const struct perf_pmu *pmu, const char *tok)
>> {
>> const char *name = pmu->name;
>> - bool need_fnmatch = strchr(tok, '*') != NULL;
>> + bool need_fnmatch = strisglob(tok);
>>
>> if (!strncmp(tok, "uncore_", 7))
>> tok += 7;
>> --
>> 2.34.1
>>
>>
>
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