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Message-ID: <2d6b9dcd-ea25-4ea7-9e35-dd36be762092@huawei.com>
Date: Wed, 21 Jan 2026 11:58:17 +0800
From: Qinxin Xia <xiaqinxin@...wei.com>
To: Ian Rogers <irogers@...gle.com>
CC: <peterz@...radead.org>, <mingo@...hat.com>, <acme@...nel.org>,
<namhyung@...nel.org>, <wangyushan12@...wei.com>, <hejunhao3@...artners.com>,
<jonathan.cameron@...wei.com>, <linux-perf-users@...r.kernel.org>,
<linux-kernel@...r.kernel.org>, <mark.rutland@....com>,
<alexander.shishkin@...ux.intel.com>, <jolsa@...nel.org>,
<adrian.hunter@...el.com>, <james.clark@...aro.org>, <linuxarm@...wei.com>
Subject: Re: [RFC PATCH] perf: Add --uncorepmu option for filtering uncore
PMUs
On 2026/1/21 11:31:01, Ian Rogers <irogers@...gle.com> wrote:
> On Tue, Jan 20, 2026 at 7:15 PM Qinxin Xia <xiaqinxin@...wei.com> wrote:
>>
>>
>>
>> On 2026/1/21 04:55:30, Ian Rogers <irogers@...gle.com> wrote:
>>> On Tue, Jan 20, 2026 at 1:51 AM Qinxin Xia <xiaqinxin@...wei.com> wrote:
>>>>
>>>> This patch adds a new --uncorepmu option to perf-stat command to allow
>>>> filtering events on specific uncore PMUs. This is useful when there are
>>>> multiple uncore PMUs with the same type (e.g. hisi_sicl2_cpa0 and
>>>> hisi_sicl0_cpa0).
>>>>
>>>> eg:
>>>> [root@...alhost tmp]# ./perf stat -M cpa_p0_avg_bw
>>>> Performance counter stats for 'system wide':
>>>>
>>>> 19,417,779,115 hisi_sicl0_cpa0/cpa_cycles/ # 0.00 cpa_p0_avg_bw
>>>> 0 hisi_sicl0_cpa0/cpa_p0_wr_dat/
>>>> 0 hisi_sicl0_cpa0/cpa_p0_rd_dat_64b/
>>>> 0 hisi_sicl0_cpa0/cpa_p0_rd_dat_32b/
>>>> 19,417,751,103 hisi_sicl10_cpa0/cpa_cycles/ # 0.00 cpa_p0_avg_bw
>>>> 0 hisi_sicl10_cpa0/cpa_p0_wr_dat/
>>>> 0 hisi_sicl10_cpa0/cpa_p0_rd_dat_64b/
>>>> 0 hisi_sicl10_cpa0/cpa_p0_rd_dat_32b/
>>>> 19,417,730,679 hisi_sicl2_cpa0/cpa_cycles/ # 0.31 cpa_p0_avg_bw
>>>> 75,635,749 hisi_sicl2_cpa0/cpa_p0_wr_dat/
>>>> 18,520,640 hisi_sicl2_cpa0/cpa_p0_rd_dat_64b/
>>>> 0 hisi_sicl2_cpa0/cpa_p0_rd_dat_32b/
>>>> 19,417,674,227 hisi_sicl8_cpa0/cpa_cycles/ # 0.00 cpa_p0_avg_bw
>>>> 0 hisi_sicl8_cpa0/cpa_p0_wr_dat/
>>>> 0 hisi_sicl8_cpa0/cpa_p0_rd_dat_64b/
>>>> 0 hisi_sicl8_cpa0/cpa_p0_rd_dat_32b/
>>>>
>>>> 19.417734480 seconds time elapsed
>>>>
>>>> [root@...alhost tmp]# ./perf stat --uncorepmu hisi_sicl2_cpa0 -M cpa_p0_avg_bw
>>>> Performance counter stats for 'system wide':
>>>>
>>>> 6,234,093,559 cpa_cycles # 0.60 cpa_p0_avg_bw
>>>> 50,548,465 cpa_p0_wr_dat
>>>> 7,552,182 cpa_p0_rd_dat_64b
>>>> 0 cpa_p0_rd_dat_32b
>>>>
>>>> 6.234139320 seconds time elapsed
>>>
>>> So normally for this case the -A/--no-merge will give you a per-PMU
>>> breakdown. It isn't restricted to a single PMU like the output here,
>>> but we similarly don't have options to restrict per-socket, per-dir,
>>> per-cluster and per-core. There is an option with --per-cache but that
>>> looks like a way to avoid having many --per-cache options rather than
>>> taking a value for a particular cache to only dump.
>>>
>>> I did deliberate make the --cputype code generic so it could be used
>>> in ways like this, but it'd be nice to glob match the names for
>>> consistency with event parsing:
>>> https://web.git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools-next.git/tree/tools/perf/util/pmu.c#n2647
>>> I needed to have --cputype as Intel's early hybrid patches had added
>>> it before I cleaned things up to be more PMU oriented.
>>>
>> Hello, Ian!
>>
>> For core-related events and metric, we usually care about which core it
>> happens on, so we can filter it with -C.
>>
>> Such as:
>>
>> [root@...alhost ~]# perf stat -C 0 -e L1-dcache-loads sleep 3
>>
>> Performance counter stats for 'CPU(s) 0':
>>
>> 136,578 L1-dcache-loads
>>
>>
>> 3.099147550 seconds time elapsed
>>
>> [root@...alhost tool]# ./perf stat -C 0 -M l1d_miss_rate sleep 3
>>
>> Performance counter stats for 'CPU(s) 0':
>>
>> 18,708 L1-dcache-load-misses # 3.6 %
>> l1d_miss_rate
>> 513,038 L1-dcache-loads
>>
>>
>> 3.004649800 seconds time elapsed
>>
>> For core-independent events and metrics such as ddrc, smmu, and cpa, we
>> care about which hardware module they occur. (The example provided in
>> commit info is sicl.) so we want to filter it by pmu, for events I can
>> filter it with'cputype' (This is a little strange because sicl does not
>> belong to any cputype.). However, metric does not support this mode.
>>
>> [root@...alhost ~]# perf stat --cputype hisi_sicl0_cpa0 -e cpa_cycles
>> sleep 3
>>
>> Performance counter stats for 'system wide':
>>
>> 3,003,492,731 cpa_cycles
>>
>>
>> 3.003484270 seconds time elapsed
>>
>>
>> [root@...alhost ~]# perf stat --cputype hisi_sicl0_cpa0 -M
>> cpa_p0_wr_dat sleep 3
>>
>> Cannot find metric or group `cpa_p0_wr_dat'
>>
>> This patch supports the metric scenario through '--uncorepmu'.
>>
>>> So I can see the purpose of this patch in being low overhead compared
>>> to -A, I'm just not sure whether this is a PMU or an aggregation
>>> option. I also think the term "uncore" is kind of confusing and so
>>> have tried to keep it away from command line options. Why isn't is it
>>> just a pmu filter?
>>>
>>> Thanks,
>>> Ian
>>>
>> Perhaps we could make cputype a little more generic so that it could
>> also include pmu-filter functionality.
>
> Yeah, that'd been my intention quite a while ago. I wanted to hide the
> cputype flag and replace it with something like --pmu-filter. Looks
> like I never got around to writing the patch though :-) I agree the -C
> filtering is similar to this and similarly different to how the
> aggregation code is working. Could we rename --uncorepmu to
> --pmu-filter then?
>
> Thanks,
> Ian
>
Thank you for the suggestions, I will rename --uncorepmu to --pmu-filter
in the next version of this patch.:-)
Regarding --cputype: would you like me to also rename it to --pmu-filter
the same patch series next version?
>>>> Signed-off-by: Qinxin Xia <xiaqinxin@...wei.com>
>>>> ---
>>>> tools/perf/Documentation/perf-stat.txt | 4 ++++
>>>> tools/perf/builtin-stat.c | 26 ++++++++++++++++++++++++++
>>>> tools/perf/util/metricgroup.c | 18 +++++++++++++-----
>>>> 3 files changed, 43 insertions(+), 5 deletions(-)
>>>>
>>>> diff --git a/tools/perf/Documentation/perf-stat.txt b/tools/perf/Documentation/perf-stat.txt
>>>> index 1a766d4a2233..9c0952b43a57 100644
>>>> --- a/tools/perf/Documentation/perf-stat.txt
>>>> +++ b/tools/perf/Documentation/perf-stat.txt
>>>> @@ -573,6 +573,10 @@ $ perf config stat.no-csv-summary=true
>>>> Only enable events on applying cpu with this type for hybrid platform
>>>> (e.g. core or atom)"
>>>>
>>>> +--uncorepmu::
>>>> +Only enable events on applying uncore pmu with specified for multiple
>>>> +uncore pmus with same type (e.g. hisi_sicl2_cpa0 or hisi_sicl0_cpa0)
>>>> +
>>>> EXAMPLES
>>>> --------
>>>>
>>>> diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
>>>> index ab40d85fb125..3f34bfc79179 100644
>>>> --- a/tools/perf/builtin-stat.c
>>>> +++ b/tools/perf/builtin-stat.c
>>>> @@ -1235,6 +1235,28 @@ static int parse_cputype(const struct option *opt,
>>>> return 0;
>>>> }
>>>>
>>>> +static int parse_uncorepmu(const struct option *opt,
>>>> + const char *str,
>>>> + int unset __maybe_unused)
>>>> +{
>>>> + const struct perf_pmu *pmu;
>>>> + struct evlist *evlist = *(struct evlist **)opt->value;
>>>> +
>>>> + if (!list_empty(&evlist->core.entries)) {
>>>> + fprintf(stderr, "Must define uncorepmu before events/metrics\n");
>>>> + return -1;
>>>> + }
>>>> +
>>>> + pmu = perf_pmus__pmu_for_pmu_filter(str);
>>>> + if (!pmu || pmu->is_core) {
>>>> + fprintf(stderr, "--uncorepmu %s is not supported!\n", str);
>>>> + return -1;
>>>> + }
>>>> + parse_events_option_args.pmu_filter = pmu->name;
>>>> +
>>>> + return 0;
>>>> +}
>>>> +
>>>> static int parse_cache_level(const struct option *opt,
>>>> const char *str,
>>>> int unset __maybe_unused)
>>>> @@ -2579,6 +2601,10 @@ int cmd_stat(int argc, const char **argv)
>>>> "Only enable events on applying cpu with this type "
>>>> "for hybrid platform (e.g. core or atom)",
>>>> parse_cputype),
>>>> + OPT_CALLBACK(0, "uncorepmu", &evsel_list, "uncore pmu",
>>>> + "Only enable events on applying uncore pmu with specified "
>>>> + "for multiple uncore pmus with same type(e.g. hisi_sicl2_cpa0 or hisi_sicl0_cpa0)",
>>>> + parse_uncorepmu),
>>>> #ifdef HAVE_LIBPFM
>>>> OPT_CALLBACK(0, "pfm-events", &evsel_list, "event",
>>>> "libpfm4 event selector. use 'perf list' to list available events",
>>>> diff --git a/tools/perf/util/metricgroup.c b/tools/perf/util/metricgroup.c
>>>> index 25c75fdbfc52..59ef71df20bd 100644
>>>> --- a/tools/perf/util/metricgroup.c
>>>> +++ b/tools/perf/util/metricgroup.c
>>>> @@ -387,8 +387,13 @@ static bool match_pm_metric_or_groups(const struct pmu_metric *pm, const char *p
>>>> const char *metric_or_groups)
>>>> {
>>>> const char *pm_pmu = pm->pmu ?: "cpu";
>>>> + struct perf_pmu *perf_pmu = NULL;
>>>>
>>>> - if (strcmp(pmu, "all") && strcmp(pm_pmu, pmu))
>>>> + if (pm->pmu)
>>>> + perf_pmu = perf_pmus__find(pm->pmu);
>>>> +
>>>> + if (strcmp(pmu, "all") && strcmp(pm_pmu, pmu) &&
>>>> + (perf_pmu && !perf_pmu__name_wildcard_match(perf_pmu, pmu)))
>>>> return false;
>>>>
>>>> return match_metric_or_groups(pm->metric_group, metric_or_groups) ||
>>>> @@ -1260,7 +1265,8 @@ static int build_combined_expr_ctx(const struct list_head *metric_list,
>>>> static int parse_ids(bool metric_no_merge, bool fake_pmu,
>>>> struct expr_parse_ctx *ids, const char *modifier,
>>>> bool group_events, const bool tool_events[TOOL_PMU__EVENT_MAX],
>>>> - struct evlist **out_evlist)
>>>> + struct evlist **out_evlist,
>>>> + const char *filter_pmu)
>>>> {
>>>> struct parse_events_error parse_error;
>>>> struct evlist *parsed_evlist;
>>>> @@ -1314,7 +1320,7 @@ static int parse_ids(bool metric_no_merge, bool fake_pmu,
>>>> }
>>>> pr_debug("Parsing metric events '%s'\n", events.buf);
>>>> parse_events_error__init(&parse_error);
>>>> - ret = __parse_events(parsed_evlist, events.buf, /*pmu_filter=*/NULL,
>>>> + ret = __parse_events(parsed_evlist, events.buf, filter_pmu,
>>>> &parse_error, fake_pmu, /*warn_if_reordered=*/false,
>>>> /*fake_tp=*/false);
>>>> if (ret) {
>>>> @@ -1417,7 +1423,8 @@ static int parse_groups(struct evlist *perf_evlist,
>>>> /*modifier=*/NULL,
>>>> /*group_events=*/false,
>>>> tool_events,
>>>> - &combined_evlist);
>>>> + &combined_evlist,
>>>> + (pmu && strcmp(pmu, "all") == 0) ? NULL : pmu);
>>>> }
>>>> if (combined)
>>>> expr__ctx_free(combined);
>>>> @@ -1472,7 +1479,8 @@ static int parse_groups(struct evlist *perf_evlist,
>>>> }
>>>> if (!metric_evlist) {
>>>> ret = parse_ids(metric_no_merge, fake_pmu, m->pctx, m->modifier,
>>>> - m->group_events, tool_events, &m->evlist);
>>>> + m->group_events, tool_events, &m->evlist,
>>>> + (pmu && strcmp(pmu, "all") == 0) ? NULL : pmu);
>>>> if (ret)
>>>> goto out;
>>>>
>>>> --
>>>> 2.33.0
>>>>
>>
>> --
>> Thanks,
>> Qinxin
>>
--
Thanks,
Qinxin
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