linux-kernel - [PATCH v1 1/4] perf evsel: Reduce scanning core PMUs in is

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Message-Id: <20250114231332.13419-2-irogers@google.com>
Date: Tue, 14 Jan 2025 15:13:29 -0800
From: Ian Rogers <irogers@...gle.com>
To: 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>, James Clark <james.clark@...aro.org>, 
	Ze Gao <zegao2021@...il.com>, Weilin Wang <weilin.wang@...el.com>, 
	Jean-Philippe Romain <jean-philippe.romain@...s.st.com>, Junhao He <hejunhao3@...wei.com>, 
	Yicong Yang <yangyicong@...ilicon.com>, linux-perf-users@...r.kernel.org, 
	linux-kernel@...r.kernel.org
Subject: [PATCH v1 1/4] perf evsel: Reduce scanning core PMUs in is_hybrid

evsel__is_hybrid returns true if there are multiple core PMUs and the
evsel is for a core PMU. Determining the number of core PMUs can
require loading/scanning PMUs. There's no point doing the scanning if
evsel for the is_hybrid test isn't core so reorder the tests to reduce
PMU scanning.

Signed-off-by: Ian Rogers <irogers@...gle.com>
---
 tools/perf/util/evsel.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index bc144388f892..ae20691bbfae 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -3856,10 +3856,10 @@ void evsel__zero_per_pkg(struct evsel *evsel)
  */
 bool evsel__is_hybrid(const struct evsel *evsel)
 {
-	if (perf_pmus__num_core_pmus() == 1)
+	if (!evsel->core.is_pmu_core)
 		return false;
 
-	return evsel->core.is_pmu_core;
+	return perf_pmus__num_core_pmus() > 1;
 }
 
 struct evsel *evsel__leader(const struct evsel *evsel)
-- 
2.48.0.rc2.279.g1de40edade-goog