linux-kernel - [PATCH v2 4/5] perf x86 evlist: Update comments on topdown regrouping

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Message-ID: <20250307023906.1135613-4-irogers@google.com>
Date: Thu,  6 Mar 2025 18:39:05 -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>, 
	Dominique Martinet <asmadeus@...ewreck.org>, Andi Kleen <ak@...ux.intel.com>, 
	linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org, 
	Dapeng Mi <dapeng1.mi@...ux.intel.com>, Thomas Falcon <thomas.falcon@...el.com>
Subject: [PATCH v2 4/5] perf x86 evlist: Update comments on topdown regrouping

From: Dapeng Mi <dapeng1.mi@...ux.intel.com>

Update to remove comments about groupings not working and with the:
```
perf stat -e "{instructions,slots},{cycles,topdown-retiring}"
```
case that now works.

Signed-off-by: Ian Rogers <irogers@...gle.com>
---
 tools/perf/arch/x86/util/evlist.c | 27 ++++++---------------------
 1 file changed, 6 insertions(+), 21 deletions(-)

diff --git a/tools/perf/arch/x86/util/evlist.c b/tools/perf/arch/x86/util/evlist.c
index ed205d1b207d..7905a28d7734 100644
--- a/tools/perf/arch/x86/util/evlist.c
+++ b/tools/perf/arch/x86/util/evlist.c
@@ -39,28 +39,13 @@ int arch_evlist__cmp(const struct evsel *lhs, const struct evsel *rhs)
 	 *         26,319,024      slots
 	 *          2,427,791      instructions
 	 *          2,683,508      topdown-retiring
-	 *
-	 * If slots event and topdown metrics events are not in same group, the
-	 * topdown metrics events must be first event after the slots event group,
-	 * otherwise topdown metrics events can't be regrouped correctly, e.g.
-	 *
-	 * a. perf stat -e "{instructions,slots},cycles,topdown-retiring" -C0 sleep 1
-	 *    WARNING: events were regrouped to match PMUs
-	 *     Performance counter stats for 'CPU(s) 0':
-	 *         17,923,134      slots
-	 *          2,154,855      instructions
-	 *          3,015,058      cycles
-	 *    <not supported>      topdown-retiring
-	 *
-	 * If slots event and topdown metrics events are in two groups, the group which
-	 * has topdown metrics events must contain only the topdown metrics event,
-	 * otherwise topdown metrics event can't be regrouped correctly as well, e.g.
-	 *
-	 * a. perf stat -e "{instructions,slots},{topdown-retiring,cycles}" -C0 sleep 1
+	 * e. slots event and metrics event are in a group and not adjacent
+	 *    perf stat -e "{instructions,slots},cycles,topdown-retiring" -C0 sleep 1
 	 *    WARNING: events were regrouped to match PMUs
-	 *    Error:
-	 *    The sys_perf_event_open() syscall returned with 22 (Invalid argument) for
-	 *    event (topdown-retiring)
+	 *         68,433,522      slots
+	 *          8,856,102      topdown-retiring
+	 *          7,791,494      instructions
+	 *         11,469,513      cycles
 	 */
 	if (topdown_sys_has_perf_metrics() &&
 	    (arch_evsel__must_be_in_group(lhs) || arch_evsel__must_be_in_group(rhs))) {
-- 
2.49.0.rc0.332.g42c0ae87b1-goog