Re: [PATCH 2/3] perf stat: Merge event counts from all hybrid PMUs
From: Xing Zhengjun
Date: Sat May 07 2022 - 01:09:58 EST
On 5/7/2022 12:03 PM, Ian Rogers wrote:
On Thu, Apr 21, 2022 at 11:57 PM <zhengjun.xing@xxxxxxxxxxxxxxx> wrote:
From: Zhengjun Xing <zhengjun.xing@xxxxxxxxxxxxxxx>
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@xxxxxxxxxxxxxxx>
Reviewed-by: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
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 -a /bin/true
Performance counter stats for 'system wide':
2,416,092 cpu_core/instructions/
305,840 cpu_atom/instructions/
2,645,138 cpu_core/cycles/
789,631 cpu_atom/cycles/
0.002345159 seconds time elapsed
# ./perf stat -e instructions,cycles -a --hybrid-merge /bin/true
Performance counter stats for 'system wide':
2,702,612 instructions
3,607,773 cycles
0.002475749 seconds time elapsed
Currently, no metrics showed for the hybrid systems.
$ 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
--
Zhengjun Xing