linux-kernel - [PATCH v1] perf pfm: Don't force loading of all PMUs

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Message-ID: <20250722013449.146233-1-irogers@google.com>
Date: Mon, 21 Jul 2025 18:34:49 -0700
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>, 
	Jean-Philippe Romain <jean-philippe.romain@...s.st.com>, linux-perf-users@...r.kernel.org, 
	linux-kernel@...r.kernel.org
Subject: [PATCH v1] perf pfm: Don't force loading of all PMUs

Force loading all PMUs adds significant cost because DRM and other
PMUs are loaded, it should also not be required if the pmus__
functions are used.

Tested by run perf test, in particular the pfm related tests. Also
`perf list` is identical before and after.

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

diff --git a/tools/perf/util/pfm.c b/tools/perf/util/pfm.c
index 0dacc133ed39..e89395814e88 100644
--- a/tools/perf/util/pfm.c
+++ b/tools/perf/util/pfm.c
@@ -47,10 +47,6 @@ int parse_libpfm_events_option(const struct option *opt, const char *str,
 	p_orig = p = strdup(str);
 	if (!p)
 		return -1;
-	/*
-	 * force loading of the PMU list
-	 */
-	perf_pmus__scan(NULL);
 
 	for (q = p; strsep(&p, ",{}"); q = p) {
 		sep = p ? str + (p - p_orig - 1) : "";
-- 
2.50.0.727.gbf7dc18ff4-goog