linux-kernel - [PATCH v1 04/12] perf parse-events: Allow the cpu term to be a PMU

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Message-ID: <20250627192417.1157736-5-irogers@google.com>
Date: Fri, 27 Jun 2025 12:24:09 -0700
From: Ian Rogers <irogers@...gle.com>
To: Thomas Falcon <thomas.falcon@...el.com>, Peter Zijlstra <peterz@...radead.org>, 
	Ingo Molnar <mingo@...hat.com>, Arnaldo Carvalho de Melo <acme@...nel.org>, Namhyung Kim <namhyung@...nel.org>, 
	Mark Rutland <mark.rutland@....com>, 
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>, Jiri Olsa <jolsa@...nel.org>, 
	Ian Rogers <irogers@...gle.com>, Adrian Hunter <adrian.hunter@...el.com>, 
	Kan Liang <kan.liang@...ux.intel.com>, Ben Gainey <ben.gainey@....com>, 
	James Clark <james.clark@...aro.org>, Howard Chu <howardchu95@...il.com>, 
	Weilin Wang <weilin.wang@...el.com>, Levi Yun <yeoreum.yun@....com>, 
	"Dr. David Alan Gilbert" <linux@...blig.org>, Zhongqiu Han <quic_zhonhan@...cinc.com>, 
	Blake Jones <blakejones@...gle.com>, Yicong Yang <yangyicong@...ilicon.com>, 
	Anubhav Shelat <ashelat@...hat.com>, Thomas Richter <tmricht@...ux.ibm.com>, 
	Jean-Philippe Romain <jean-philippe.romain@...s.st.com>, Song Liu <song@...nel.org>, 
	linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH v1 04/12] perf parse-events: Allow the cpu term to be a PMU

On hybrid systems, events like msr/tsc/ will aggregate counts across
all CPUs. Often metrics only want a value like msr/tsc/ for the cores
on which the metric is being computed. Listing each CPU with terms
cpu=0,cpu=1.. is laborious and would need to be encoded for all
variations of a CPU model.

Allow the cpumask from a PMU to be an argument to the cpu term. For
example in the following the cpumask of the cstate_pkg PMU selects the
CPUs to count msr/tsc/ counter upon:
```
$ cat /sys/bus/event_source/devices/cstate_pkg/cpumask
0
$ perf stat -A -e 'msr/tsc,cpu=cstate_pkg/' -a sleep 0.1

 Performance counter stats for 'system wide':

CPU0          252,621,253      msr/tsc,cpu=cstate_pkg/

       0.101184092 seconds time elapsed
```

Signed-off-by: Ian Rogers <irogers@...gle.com>
---
 tools/perf/util/parse-events.c | 37 +++++++++++++++++++++++++---------
 1 file changed, 28 insertions(+), 9 deletions(-)

diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index 7a32d5234a64..ef38eb082342 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -192,10 +192,20 @@ static struct perf_cpu_map *get_config_cpu(const struct parse_events_terms *head
 
 	list_for_each_entry(term, &head_terms->terms, list) {
 		if (term->type_term == PARSE_EVENTS__TERM_TYPE_CPU) {
-			struct perf_cpu_map *cpu = perf_cpu_map__new_int(term->val.num);
+			struct perf_cpu_map *term_cpus;
 
-			perf_cpu_map__merge(&cpus, cpu);
-			perf_cpu_map__put(cpu);
+			if (term->type_val == PARSE_EVENTS__TERM_TYPE_NUM) {
+				term_cpus = perf_cpu_map__new_int(term->val.num);
+			} else {
+				struct perf_pmu *pmu = perf_pmus__find(term->val.str);
+
+				if (perf_cpu_map__is_empty(pmu->cpus))
+					term_cpus = pmu->is_core ? cpu_map__online() : NULL;
+				else
+					term_cpus = perf_cpu_map__get(pmu->cpus);
+			}
+			perf_cpu_map__merge(&cpus, term_cpus);
+			perf_cpu_map__put(term_cpus);
 		}
 	}
 
@@ -1054,12 +1064,21 @@ do {									   \
 		}
 		break;
 	case PARSE_EVENTS__TERM_TYPE_CPU:
-		CHECK_TYPE_VAL(NUM);
-		if (term->val.num >= (u64)cpu__max_present_cpu().cpu) {
-			parse_events_error__handle(err, term->err_val,
-						strdup("too big"),
-						NULL);
-			return -EINVAL;
+		if (term->type_val == PARSE_EVENTS__TERM_TYPE_NUM) {
+			if (term->val.num >= (u64)cpu__max_present_cpu().cpu) {
+				parse_events_error__handle(err, term->err_val,
+							strdup("too big"),
+							/*help=*/NULL);
+				return -EINVAL;
+			}
+		} else {
+			assert(term->type_val == PARSE_EVENTS__TERM_TYPE_STR);
+			if (perf_pmus__find(term->val.str) == NULL) {
+				parse_events_error__handle(err, term->err_val,
+							strdup("not a valid PMU"),
+							/*help=*/NULL);
+				return -EINVAL;
+			}
 		}
 		break;
 	case PARSE_EVENTS__TERM_TYPE_DRV_CFG:
-- 
2.50.0.727.gbf7dc18ff4-goog