Re: [PATCH v1] perf pmu: Recognize default_core as a core PMU in more places

[Qinxin Xia <xiaqinxin@huawei.com>]

On 2026/6/23 01:53:52, Ian Rogers <irogers@google.com> wrote:
> On Mon, Jun 22, 2026 at 2:11 AM Qinxin Xia<xiaqinxin@huawei.com> wrote:
>>
>>
>> On 2026/6/12 09:24:13, Ian Rogers<irogers@google.com> wrote:
>>> The python metrics code used in places like ilist.py passes a
>>> pmu-filter of "default_core" on non-hybrid x86/ARM/.. systems. As a
>>> PMU like "cpu" isn't a literal name match then no PMU matches
>>> "default_core" and the events fail to parse for the metric. Fix the
>>> name matching and PMU lookup for "default_core" and check that it
>>> fixes ilist.py.
>>>
>>> Fixes: 74e2dbe7be50 ("perf tools: Add --pmu-filter option for filtering PMUs")
>>> Signed-off-by: Ian Rogers<irogers@google.com>
>>> ---
>>> Note: this bug is in 7.1 but it is a little too late to send for the
>>>         release. It should get picked up via the fixes tag.
>>> ---
>>>    tools/perf/util/pmu.c  | 6 +++++-
>>>    tools/perf/util/pmus.c | 2 ++
>>>    2 files changed, 7 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
>>> index a550f030b85d..836e3b5615cd 100644
>>> --- a/tools/perf/util/pmu.c
>>> +++ b/tools/perf/util/pmu.c
>>> @@ -2660,8 +2660,12 @@ bool perf_pmu__wildcard_match(const struct perf_pmu *pmu, const char *wildcard_t
>>>                pmu->name,
>>>                pmu->alias_name,
>>>        };
>>> -     bool need_fnmatch = strisglob(wildcard_to_match);
>>> +     bool need_fnmatch;
>>>
>>> +     if (pmu->is_core && !strcmp(wildcard_to_match, "default_core"))
>>> +             return true;
>>> +
>>> +     need_fnmatch = strisglob(wildcard_to_match);
>>>        if (!strncmp(wildcard_to_match, "uncore_", 7))
>>>                wildcard_to_match += 7;
>>>
>>> diff --git a/tools/perf/util/pmus.c b/tools/perf/util/pmus.c
>>> index 5e3f571450fe..e0a4cb2428ca 100644
>>> --- a/tools/perf/util/pmus.c
>>> +++ b/tools/perf/util/pmus.c
>>> @@ -150,6 +150,8 @@ struct perf_pmu *perf_pmus__find(const char *name)
>>>        bool core_pmu;
>>>        unsigned int to_read_pmus = 0;
>>>
>>> +     if (!strcmp(name, "default_core"))
>>> +             return perf_pmus__find_core_pmu();
>>>        /*
>>>         * Once PMU is loaded it stays in the list,
>>>         * so we keep us from multiple reading/parsing
>> Thank you for the fix, Ian.
>> In the previous patch, I overlooked the handling of the "default_core"
>> alias. Also, perhaps we can leave need_fnmatch as-is, since it doesn't
>> seem to affect anything here.
> Thanks. I moved need_fnmatch's initialization just to save some work
> in the "default_core" case where the value is unused. While leaving it
> in place would reduce the diff, I think the optimization is worth it
> as we would otherwise call strisglob when say iterating all metrics.
> 
Perhaps we can do it this way：
	if (pmu->is_core && !strcmp(wildcard_to_match, "default_core"))
              	return true;

	bool need_fnmatch = strisglob(wildcard_to_match);
> Would it be okay to supply a Reviewed-by tag? I notice this fix is
> missing from perf-tools-next.
> 
Sure, add my Reviewed‑by.:-)

> Thanks!
> Ian
> 
>> --
>> Thanks,
>> Qinxin

-- 
Thanks,
Qinxin