From: Chun-Tse Shao <ctshao@google.com>
To: peterz@infradead.org, mingo@redhat.com, acme@kernel.org,
namhyung@kernel.org
Cc: alexander.shishkin@linux.intel.com, jolsa@kernel.org,
adrian.hunter@intel.com, james.clark@linaro.org,
afaerber@suse.de, mani@kernel.org, dapeng1.mi@linux.intel.com,
thomas.falcon@intel.com, irogers@google.com,
linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org,
Chun-Tse Shao <ctshao@google.com>
Subject: [PATCH] perf stat: Include PMU name and split uncore events per PMU in metric-only JSON output
Date: Tue, 14 Jul 2026 10:40:52 -0700 [thread overview]
Message-ID: <20260714174052.1826692-1-ctshao@google.com> (raw)
When running `perf stat` with `-A` (--no-aggr) and `--metric-only` in
JSON output mode (`-j`), `perf stat` evaluates metric expressions
across all matching PMUs (including uncore PMUs like `uncore_iio_0`,
`uncore_iio_1`, etc.).
However, `perf stat` previously formatted JSON output by printing only
"cpu" : "<id>" and grouping all metric values on a single line per CPU
without identifying which PMU instance evaluated each metric. As a
result, when an uncore event spans multiple PMU boxes, `perf stat`
printed repeated, ambiguous metric keys without PMU names.
Fix this by:
1. Including "pmu" : "<pmu_name>" in print_aggr_id_json when evsel->pmu
is a non-core or hybrid PMU in AGGR_NONE mode (-A).
2. Starting a new JSON metric line in AGGR_NONE mode (-A) whenever the
underlying PMU instance changes across PMU events.
3. Updating perf_json_output_lint.py to recognize the new "pmu" key in
the JSON test suite.
Example output:
$ perf stat -M iio_bandwidth_read -a -A --metric-only -j -I 1000
{"interval" : 1.000314908, "cpu" : "0", "pmu" : "uncore_iio_0", "MB/s iio_bandwidth_read" : "0.0"}
{"interval" : 1.000314908, "cpu" : "0", "pmu" : "uncore_iio_1", "MB/s iio_bandwidth_read" : "0.1"}
{"interval" : 1.000314908, "cpu" : "0", "pmu" : "uncore_iio_11", "MB/s iio_bandwidth_read" : "0.0"}
...
{"interval" : 1.000314908, "cpu" : "56", "pmu" : "uncore_iio_0", "MB/s iio_bandwidth_read" : "0.0"}
{"interval" : 1.000314908, "cpu" : "56", "pmu" : "uncore_iio_1", "MB/s iio_bandwidth_read" : "0.0"}
{"interval" : 1.000314908, "cpu" : "56", "pmu" : "uncore_iio_11", "MB/s iio_bandwidth_read" : "0.0"}
Signed-off-by: Chun-Tse Shao <ctshao@google.com>
Assisted-by: Gemini:gemini-3.1-pro-preview
---
.../tests/shell/lib/perf_json_output_lint.py | 1 +
tools/perf/util/stat-display.c | 41 +++++++++++++------
2 files changed, 30 insertions(+), 12 deletions(-)
diff --git a/tools/perf/tests/shell/lib/perf_json_output_lint.py b/tools/perf/tests/shell/lib/perf_json_output_lint.py
index dafbde56cc76..36767905fcdb 100644
--- a/tools/perf/tests/shell/lib/perf_json_output_lint.py
+++ b/tools/perf/tests/shell/lib/perf_json_output_lint.py
@@ -64,6 +64,7 @@ def check_json_output(expected_items):
'metric-threshold': lambda x: x in ['unknown', 'good', 'less good', 'nearly bad', 'bad'],
'metricgroup': lambda x: True,
'node': lambda x: True,
+ 'pmu': lambda x: True,
'pcnt-running': lambda x: isfloat(x),
'socket': lambda x: True,
'thread': lambda x: True,
diff --git a/tools/perf/util/stat-display.c b/tools/perf/util/stat-display.c
index f94f1324d24a..d7f1feb63878 100644
--- a/tools/perf/util/stat-display.c
+++ b/tools/perf/util/stat-display.c
@@ -397,6 +397,8 @@ static void print_aggr_id_json(struct perf_stat_config *config, struct outstate
json_out(os, "\"cpu\" : \"%d\"",
id.cpu.cpu);
}
+ if (evsel && evsel->pmu && (!evsel->pmu->is_core || evsel__is_hybrid(evsel)))
+ json_out(os, "\"pmu\" : \"%s\"", evsel->pmu->name);
break;
case AGGR_THREAD:
json_out(os, "\"thread\" : \"%s-%d\"",
@@ -1009,11 +1011,12 @@ static void print_counter_aggrdata(struct perf_stat_config *config,
static void print_metric_begin(struct perf_stat_config *config,
struct evlist *evlist,
- struct outstate *os, int aggr_idx)
+ struct outstate *os, int aggr_idx,
+ struct evsel *counter)
{
struct perf_stat_aggr *aggr;
struct aggr_cpu_id id;
- struct evsel *evsel;
+ struct evsel *evsel = counter ?: evlist__first(evlist);
os->first = true;
if (!config->metric_only)
@@ -1028,7 +1031,6 @@ static void print_metric_begin(struct perf_stat_config *config,
else
fprintf(config->output, "%s", os->timestamp);
}
- evsel = evlist__first(evlist);
id = config->aggr_map->map[aggr_idx];
aggr = &evsel->stats->aggr[aggr_idx];
aggr_printout(config, os, evsel, id, aggr->nr);
@@ -1066,7 +1068,7 @@ static void print_aggr(struct perf_stat_config *config,
* Without each counter has its own line.
*/
cpu_aggr_map__for_each_idx(aggr_idx, config->aggr_map) {
- print_metric_begin(config, evlist, os, aggr_idx);
+ print_metric_begin(config, evlist, os, aggr_idx, NULL);
evlist__for_each_entry(evlist, counter) {
print_counter_aggrdata(config, counter, aggr_idx, os);
@@ -1092,7 +1094,7 @@ static void print_aggr_cgroup(struct perf_stat_config *config,
os->cgrp = evsel->cgrp;
cpu_aggr_map__for_each_idx(aggr_idx, config->aggr_map) {
- print_metric_begin(config, evlist, os, aggr_idx);
+ print_metric_begin(config, evlist, os, aggr_idx, NULL);
evlist__for_each_entry(evlist, counter) {
if (counter->cgrp != os->cgrp)
@@ -1128,7 +1130,8 @@ static void print_no_aggr_metric(struct perf_stat_config *config,
perf_cpu_map__for_each_cpu(cpu, all_idx, evlist__core(evlist)->user_requested_cpus) {
struct evsel *counter;
- bool first = true;
+ struct perf_pmu *last_pmu = NULL;
+ bool line_open = false;
evlist__for_each_entry(evlist, counter) {
u64 ena, run, val;
@@ -1146,10 +1149,24 @@ static void print_no_aggr_metric(struct perf_stat_config *config,
os->evsel = counter;
os->id = aggr_cpu_id__cpu(cpu, /*data=*/NULL);
- if (first) {
- print_metric_begin(config, evlist, os, aggr_idx);
- first = false;
+
+ if (config->metric_only) {
+ struct perf_pmu *pmu = counter->pmu;
+
+ if (!evsel__is_tool(counter)) {
+ if (config->json_output && line_open && pmu != last_pmu) {
+ print_metric_end(config, os);
+ line_open = false;
+ }
+ if (!line_open) {
+ print_metric_begin(config, evlist, os,
+ aggr_idx, counter);
+ line_open = true;
+ last_pmu = pmu;
+ }
+ }
}
+
val = ps->aggr[aggr_idx].counts.val;
ena = ps->aggr[aggr_idx].counts.ena;
run = ps->aggr[aggr_idx].counts.run;
@@ -1157,7 +1174,7 @@ static void print_no_aggr_metric(struct perf_stat_config *config,
uval = val * counter->scale;
printout(config, os, uval, run, ena, 1.0, aggr_idx);
}
- if (!first)
+ if (line_open)
print_metric_end(config, os);
}
}
@@ -1520,7 +1537,7 @@ static void print_cgroup_counter(struct perf_stat_config *config, struct evlist
print_metric_end(config, os);
os->cgrp = counter->cgrp;
- print_metric_begin(config, evlist, os, /*aggr_idx=*/0);
+ print_metric_begin(config, evlist, os, /*aggr_idx=*/0, NULL);
}
print_counter(config, counter, os);
@@ -1570,7 +1587,7 @@ void evlist__print_counters(struct evlist *evlist, struct perf_stat_config *conf
} else if (config->cgroup_list) {
print_cgroup_counter(config, evlist, &os);
} else {
- print_metric_begin(config, evlist, &os, /*aggr_idx=*/0);
+ print_metric_begin(config, evlist, &os, /*aggr_idx=*/0, NULL);
evlist__for_each_entry(evlist, counter) {
print_counter(config, counter, &os);
}
--
2.55.0.141.g00534a21ce-goog
next reply other threads:[~2026-07-14 17:41 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-14 17:40 Chun-Tse Shao [this message]
2026-07-14 18:10 ` [PATCH] perf stat: Include PMU name and split uncore events per PMU in metric-only JSON output sashiko-bot
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