Messages in this thread Patch in this message | | | From | Ian Rogers <> | Date | Mon, 16 May 2022 20:11:11 -0700 | Subject | Re: [PATCH V2 2/4] perf stat: Always keep perf metrics topdown events in a group |
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On Mon, May 16, 2022 at 8:25 AM <kan.liang@linux.intel.com> wrote: > > From: Kan Liang <kan.liang@linux.intel.com> > > If any member in a group has a different cpu mask than the other > members, the current perf stat disables group. when the perf metrics > topdown events are part of the group, the below <not supported> error > will be triggered. > > $ perf stat -e "{slots,topdown-retiring,uncore_imc_free_running_0/dclk/}" -a sleep 1 > WARNING: grouped events cpus do not match, disabling group: > anon group { slots, topdown-retiring, uncore_imc_free_running_0/dclk/ } > > Performance counter stats for 'system wide': > > 141,465,174 slots > <not supported> topdown-retiring > 1,605,330,334 uncore_imc_free_running_0/dclk/ > > The perf metrics topdown events must always be grouped with a slots > event as leader. > > Factor out evsel__remove_from_group() to only remove the regular events > from the group. > > Remove evsel__must_be_in_group(), since no one use it anymore. > > With the patch, the topdown events aren't broken from the group for the > splitting. > > $ perf stat -e "{slots,topdown-retiring,uncore_imc_free_running_0/dclk/}" -a sleep 1 > WARNING: grouped events cpus do not match, disabling group: > anon group { slots, topdown-retiring, uncore_imc_free_running_0/dclk/ } > > Performance counter stats for 'system wide': > > 346,110,588 slots > 124,608,256 topdown-retiring > 1,606,869,976 uncore_imc_free_running_0/dclk/ > > 1.003877592 seconds time elapsed > > Fixes: a9a1790247bd ("perf stat: Ensure group is defined on top of the same cpu mask") > Signed-off-by: Kan Liang <kan.liang@linux.intel.com> > --- > tools/perf/builtin-stat.c | 7 +++---- > tools/perf/util/evlist.c | 6 +----- > tools/perf/util/evsel.c | 13 +++++++++++-- > tools/perf/util/evsel.h | 2 +- > 4 files changed, 16 insertions(+), 12 deletions(-) > > diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c > index a96f106dc93a..75c88c7939b1 100644 > --- a/tools/perf/builtin-stat.c > +++ b/tools/perf/builtin-stat.c > @@ -271,10 +271,9 @@ static void evlist__check_cpu_maps(struct evlist *evlist) > pr_warning(" %s: %s\n", evsel->name, buf); > } > > - for_each_group_evsel(pos, leader) { > - evsel__set_leader(pos, pos); > - pos->core.nr_members = 0; > - } > + for_each_group_evsel(pos, leader) > + evsel__remove_from_group(pos, leader); > + > evsel->core.leader->nr_members = 0;
This shouldn't be necessary now.
> } > } > diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c > index dfa65a383502..7fc544330fea 100644 > --- a/tools/perf/util/evlist.c > +++ b/tools/perf/util/evlist.c > @@ -1795,11 +1795,7 @@ struct evsel *evlist__reset_weak_group(struct evlist *evsel_list, struct evsel * > * them. Some events, like Intel topdown, require being > * in a group and so keep these in the group. > */ > - if (!evsel__must_be_in_group(c2) && c2 != leader) { > - evsel__set_leader(c2, c2); > - c2->core.nr_members = 0; > - leader->core.nr_members--; > - } > + evsel__remove_from_group(c2, leader); > > /* > * Set this for all former members of the group > diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c > index b98882cbb286..deb428ee5e50 100644 > --- a/tools/perf/util/evsel.c > +++ b/tools/perf/util/evsel.c > @@ -3083,7 +3083,16 @@ bool __weak arch_evsel__must_be_in_group(const struct evsel *evsel __maybe_unuse > return false; > } > > -bool evsel__must_be_in_group(const struct evsel *evsel) > +/* > + * Remove an event from a given group (leader). > + * Some events, e.g., perf metrics Topdown events, > + * must always be grouped. Ignore the events. > + */ > +void evsel__remove_from_group(struct evsel *evsel, struct evsel *leader) > { > - return arch_evsel__must_be_in_group(evsel); > + if (!arch_evsel__must_be_in_group(evsel) && evsel != leader) { > + evsel__set_leader(evsel, evsel); > + evsel->core.nr_members = 0; > + leader->core.nr_members--; > + }
Should we also have:
if (leader->core.nr_members == 1) leader->core.nr_members = 0;
Other wise say:
{instructions,cycles}
with a remove of cycles becomes:
{instructions}, cycles
rather than the previous:
instructions,cycles
Actually, looking at: https://lore.kernel.org/lkml/20220512061308.1152233-2-irogers@google.com/
+ /* Reset the leader count if all entries were removed. */ + if (leader->core.nr_members) + leader->core.nr_members = 0;
is wrong and should be:
+ /* Reset the leader count if all entries were removed. */ + if (leader->core.nr_members == 1) + leader->core.nr_members = 0;
I'll fix and re-send.
Thanks, Ian
> } > diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h > index a36172ed4cf6..47f65f8e7c74 100644 > --- a/tools/perf/util/evsel.h > +++ b/tools/perf/util/evsel.h > @@ -483,7 +483,7 @@ bool evsel__has_leader(struct evsel *evsel, struct evsel *leader); > bool evsel__is_leader(struct evsel *evsel); > void evsel__set_leader(struct evsel *evsel, struct evsel *leader); > int evsel__source_count(const struct evsel *evsel); > -bool evsel__must_be_in_group(const struct evsel *evsel); > +void evsel__remove_from_group(struct evsel *evsel, struct evsel *leader); > > bool arch_evsel__must_be_in_group(const struct evsel *evsel); > > -- > 2.35.1 >
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