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Message-ID: <CAP-5=fWdOv4TYHHm18-jKYP9++gEEBvTtA=5H=H3qG3iT6S8yg@mail.gmail.com>
Date: Tue, 20 Jan 2026 19:31:01 -0800
From: Ian Rogers <irogers@...gle.com>
To: Qinxin Xia <xiaqinxin@...wei.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 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
> >> 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
>
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