Messages in this thread | ![/](/images/icornerl.gif) | | From | Ian Rogers <> | Date | Wed, 25 Jan 2023 16:10:39 -0800 | Subject | Re: [PATCH v2] perf stat: Hide invalid uncore event output for aggr mode |
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On Wed, Jan 25, 2023 at 11:24 AM Namhyung Kim <namhyung@kernel.org> wrote: > > The current display code for perf stat iterates given cpus and build the > aggr map to collect the event data for the aggregation mode. > > But uncore events have their own cpu maps and it won't guarantee that > it'd match to the aggr map. For example, per-package uncore events > would generate a single value for each socket. When user asks per-core > aggregation mode, the output would contain 0 values for other cores. > > Thus it needs to check the uncore PMU's cpumask and if it matches to the > current aggregation id. > > Before: > $ sudo ./perf stat -a --per-core -e power/energy-pkg/ sleep 1 > > Performance counter stats for 'system wide': > > S0-D0-C0 1 3.73 Joules power/energy-pkg/ > S0-D0-C1 0 <not counted> Joules power/energy-pkg/ > S0-D0-C2 0 <not counted> Joules power/energy-pkg/ > S0-D0-C3 0 <not counted> Joules power/energy-pkg/ > > 1.001404046 seconds time elapsed > > Some events weren't counted. Try disabling the NMI watchdog: > echo 0 > /proc/sys/kernel/nmi_watchdog > perf stat ... > echo 1 > /proc/sys/kernel/nmi_watchdog > > The core 1, 2 and 3 should not be printed because the event is handled > in a cpu in the core 0 only. With this change, the output becomes like > below. > > After: > $ sudo ./perf stat -a --per-core -e power/energy-pkg/ sleep 1 > > Performance counter stats for 'system wide': > > S0-D0-C0 1 2.09 Joules power/energy-pkg/ > > Fixes: b89761351089 ("perf stat: Update event skip condition for system-wide per-thread mode and merged uncore and hybrid events") > Cc: Athira Jajeev <atrajeev@linux.vnet.ibm.com> > Cc: Michael Petlan <mpetlan@redhat.com> > Tested-by: Ian Rogers <irogers@google.com> > Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Ian Rogers <irogers@google.com>
Thanks, Ian
> --- > * rename to 'should_skip_zero_counter' > * check pmu->cpus instead > * add kernel-doc style comments > * add Ian's Tested-by tag > > tools/perf/util/stat-display.c | 51 ++++++++++++++++++++++++++++++---- > 1 file changed, 46 insertions(+), 5 deletions(-) > > diff --git a/tools/perf/util/stat-display.c b/tools/perf/util/stat-display.c > index 8bd8b0142630..1b5cb20efd23 100644 > --- a/tools/perf/util/stat-display.c > +++ b/tools/perf/util/stat-display.c > @@ -787,6 +787,51 @@ static void uniquify_counter(struct perf_stat_config *config, struct evsel *coun > uniquify_event_name(counter); > } > > +/** > + * should_skip_zero_count() - Check if the event should print 0 values. > + * @config: The perf stat configuration (including aggregation mode). > + * @counter: The evsel with its associated cpumap. > + * @id: The aggregation id that is being queried. > + * > + * Due to mismatch between the event cpumap or thread-map and the > + * aggregation mode, sometimes it'd iterate the counter with the map > + * which does not contain any values. > + * > + * For example, uncore events have dedicated CPUs to manage them, > + * result for other CPUs should be zero and skipped. > + * > + * Return: %true if the value should NOT be printed, %false if the value > + * needs to be printed like "<not counted>" or "<not supported>". > + */ > +static bool should_skip_zero_counter(struct perf_stat_config *config, > + struct evsel *counter, > + const struct aggr_cpu_id *id) > +{ > + struct perf_cpu cpu; > + int idx; > + > + /* > + * Skip value 0 when enabling --per-thread globally, > + * otherwise it will have too many 0 output. > + */ > + if (config->aggr_mode == AGGR_THREAD && config->system_wide) > + return true; > + /* > + * Skip value 0 when it's an uncore event and the given aggr id > + * does not belong to the PMU cpumask. > + */ > + if (!counter->pmu || !counter->pmu->is_uncore) > + return false; > + > + perf_cpu_map__for_each_cpu(cpu, idx, counter->pmu->cpus) { > + struct aggr_cpu_id own_id = config->aggr_get_id(config, cpu); > + > + if (aggr_cpu_id__equal(id, &own_id)) > + return false; > + } > + return true; > +} > + > static void print_counter_aggrdata(struct perf_stat_config *config, > struct evsel *counter, int s, > struct outstate *os) > @@ -814,11 +859,7 @@ static void print_counter_aggrdata(struct perf_stat_config *config, > ena = aggr->counts.ena; > run = aggr->counts.run; > > - /* > - * Skip value 0 when enabling --per-thread globally, otherwise it will > - * have too many 0 output. > - */ > - if (val == 0 && config->aggr_mode == AGGR_THREAD && config->system_wide) > + if (val == 0 && should_skip_zero_counter(config, counter, &id)) > return; > > if (!metric_only) { > -- > 2.39.1.456.gfc5497dd1b-goog >
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