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Date: Fri, 6 May 2022 21:03:16 -0700
From: Ian Rogers <irogers@...gle.com>
To: zhengjun.xing@...ux.intel.com
Cc: acme@...nel.org, peterz@...radead.org, mingo@...hat.com,
alexander.shishkin@...el.com, jolsa@...hat.com,
linux-kernel@...r.kernel.org, linux-perf-users@...r.kernel.org,
adrian.hunter@...el.com, ak@...ux.intel.com,
kan.liang@...ux.intel.com
Subject: Re: [PATCH 2/3] perf stat: Merge event counts from all hybrid PMUs
On Thu, Apr 21, 2022 at 11:57 PM <zhengjun.xing@...ux.intel.com> wrote:
>
> From: Zhengjun Xing <zhengjun.xing@...ux.intel.com>
>
> For hybrid events, by default stat aggregates and reports the event counts
> per pmu.
>
> # ./perf stat -e cycles -a sleep 1
>
> Performance counter stats for 'system wide':
>
> 14,066,877,268 cpu_core/cycles/
> 6,814,443,147 cpu_atom/cycles/
>
> 1.002760625 seconds time elapsed
>
> Sometimes, it's also useful to aggregate event counts from all PMUs.
> Create a new option '--hybrid-merge' to enable that behavior and report
> the counts without PMUs.
>
> # ./perf stat -e cycles -a --hybrid-merge sleep 1
>
> Performance counter stats for 'system wide':
>
> 20,732,982,512 cycles
>
> 1.002776793 seconds time elapsed
>
> Signed-off-by: Zhengjun Xing <zhengjun.xing@...ux.intel.com>
> Reviewed-by: Kan Liang <kan.liang@...ux.intel.com>
This feels related to aggregation, but aggregation is for a single
evsel on a single PMU. What happens if you have both instructions and
cycles with --hybrid-merge? Normally we aggregate all counts for each
CPU into a the two evsels and then compute a metric:
```
$ perf stat -e instructions,cycles /bin/true
Performance counter stats for '/bin/true':
1,830,554 instructions # 1.17 insn per
cycle
1,561,415 cycles
```
This kind of aggregation behavior may be needed more widely for metrics.
Thanks,
Ian
> ---
> tools/perf/Documentation/perf-stat.txt | 10 ++++++++++
> tools/perf/builtin-stat.c | 2 ++
> tools/perf/util/stat-display.c | 17 +++++++++++++++--
> tools/perf/util/stat.h | 1 +
> 4 files changed, 28 insertions(+), 2 deletions(-)
>
> diff --git a/tools/perf/Documentation/perf-stat.txt b/tools/perf/Documentation/perf-stat.txt
> index c06c341e72b9..8d1cde00b8d6 100644
> --- a/tools/perf/Documentation/perf-stat.txt
> +++ b/tools/perf/Documentation/perf-stat.txt
> @@ -454,6 +454,16 @@ Multiple events are created from a single event specification when:
> 2. Aliases, which are listed immediately after the Kernel PMU events
> by perf list, are used.
>
> +--hybrid-merge::
> +Merge the hybrid event counts from all PMUs.
> +
> +For hybrid events, by default, the stat aggregates and reports the event
> +counts per PMU. But sometimes, it's also useful to aggregate event counts
> +from all PMUs. This option enables that behavior and reports the counts
> +without PMUs.
> +
> +For non-hybrid events, it should be no effect.
> +
> --smi-cost::
> Measure SMI cost if msr/aperf/ and msr/smi/ events are supported.
>
> diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
> index a96f106dc93a..ea88ac5bed2d 100644
> --- a/tools/perf/builtin-stat.c
> +++ b/tools/perf/builtin-stat.c
> @@ -1235,6 +1235,8 @@ static struct option stat_options[] = {
> OPT_SET_UINT('A', "no-aggr", &stat_config.aggr_mode,
> "disable CPU count aggregation", AGGR_NONE),
> OPT_BOOLEAN(0, "no-merge", &stat_config.no_merge, "Do not merge identical named events"),
> + OPT_BOOLEAN(0, "hybrid-merge", &stat_config.hybrid_merge,
> + "Merge identical named hybrid events"),
> OPT_STRING('x', "field-separator", &stat_config.csv_sep, "separator",
> "print counts with custom separator"),
> OPT_CALLBACK('G', "cgroup", &evsel_list, "name",
> diff --git a/tools/perf/util/stat-display.c b/tools/perf/util/stat-display.c
> index 46b3dd134656..d9629a83aa78 100644
> --- a/tools/perf/util/stat-display.c
> +++ b/tools/perf/util/stat-display.c
> @@ -612,6 +612,19 @@ static bool hybrid_uniquify(struct evsel *evsel)
> return perf_pmu__has_hybrid() && !is_uncore(evsel);
> }
>
> +static bool hybrid_merge(struct evsel *counter, struct perf_stat_config *config,
> + bool check)
> +{
> + if (hybrid_uniquify(counter)) {
> + if (check)
> + return config && config->hybrid_merge;
> + else
> + return config && !config->hybrid_merge;
> + }
> +
> + return false;
> +}
> +
> static bool collect_data(struct perf_stat_config *config, struct evsel *counter,
> void (*cb)(struct perf_stat_config *config, struct evsel *counter, void *data,
> bool first),
> @@ -620,9 +633,9 @@ static bool collect_data(struct perf_stat_config *config, struct evsel *counter,
> if (counter->merged_stat)
> return false;
> cb(config, counter, data, true);
> - if (config->no_merge || hybrid_uniquify(counter))
> + if (config->no_merge || hybrid_merge(counter, config, false))
> uniquify_event_name(counter, config);
> - else if (counter->auto_merge_stats)
> + else if (counter->auto_merge_stats || hybrid_merge(counter, config, true))
> collect_all_aliases(config, counter, cb, data);
> return true;
> }
> diff --git a/tools/perf/util/stat.h b/tools/perf/util/stat.h
> index 335d19cc3063..91d989dfeca4 100644
> --- a/tools/perf/util/stat.h
> +++ b/tools/perf/util/stat.h
> @@ -122,6 +122,7 @@ struct perf_stat_config {
> bool ru_display;
> bool big_num;
> bool no_merge;
> + bool hybrid_merge;
> bool walltime_run_table;
> bool all_kernel;
> bool all_user;
> --
> 2.25.1
>
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