linux-kernel - [PATCH v1 2/2] perf pmu: Remove a hard coded cpu PMU assumption

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Date:   Wed, 21 Jun 2023 22:03:29 -0700
From:   Ian Rogers <irogers@...gle.com>
To:     Thomas Richter <tmricht@...ux.ibm.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...nel.org>,
        Namhyung Kim <namhyung@...nel.org>,
        Ian Rogers <irogers@...gle.com>,
        Adrian Hunter <adrian.hunter@...el.com>,
        Kan Liang <kan.liang@...ux.intel.com>,
        James Clark <james.clark@....com>,
        Ravi Bangoria <ravi.bangoria@....com>,
        linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH v1 2/2] perf pmu: Remove a hard coded cpu PMU assumption

The property of "cpu" when it has no cpu map is true on S390 with the
PMU cpum_cf. Rather than maintain a list of such PMUs, reuse the
is_core test result from the caller.

Signed-off-by: Ian Rogers <irogers@...gle.com>
---
 tools/perf/util/pmu.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index 963c12f910c5..64fa568a5426 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -551,7 +551,7 @@ static int pmu_alias_terms(struct perf_pmu_alias *alias,
  * Uncore PMUs have a "cpumask" file under sysfs. CPU PMUs (e.g. on arm/arm64)
  * may have a "cpus" file.
  */
-static struct perf_cpu_map *pmu_cpumask(int dirfd, const char *name)
+static struct perf_cpu_map *pmu_cpumask(int dirfd, const char *name, bool is_core)
 {
 	struct perf_cpu_map *cpus;
 	const char *templates[] = {
@@ -575,7 +575,8 @@ static struct perf_cpu_map *pmu_cpumask(int dirfd, const char *name)
 			return cpus;
 	}
 
-	return !strcmp(name, "cpu") ? perf_cpu_map__get(cpu_map__online()) : NULL;
+	/* Nothing found, for core PMUs assume this means all CPUs. */
+	return is_core ? perf_cpu_map__get(cpu_map__online()) : NULL;
 }
 
 static bool pmu_is_uncore(int dirfd, const char *name)
@@ -886,7 +887,8 @@ struct perf_pmu *perf_pmu__lookup(struct list_head *pmus, int dirfd, const char
 	if (!pmu)
 		return NULL;
 
-	pmu->cpus = pmu_cpumask(dirfd, name);
+	pmu->is_core = is_pmu_core(name);
+	pmu->cpus = pmu_cpumask(dirfd, name, pmu->is_core);
 	pmu->name = strdup(name);
 	if (!pmu->name)
 		goto err;
@@ -903,7 +905,6 @@ struct perf_pmu *perf_pmu__lookup(struct list_head *pmus, int dirfd, const char
 	}
 
 	pmu->type = type;
-	pmu->is_core = is_pmu_core(name);
 	pmu->is_uncore = pmu_is_uncore(dirfd, name);
 	if (pmu->is_uncore)
 		pmu->id = pmu_id(name);
-- 
2.41.0.162.gfafddb0af9-goog