linux-kernel - Re: [PATCH] perf stat: Fix uniquify for hybrid systems

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Message-ID: <Z8JQRbjuhILt7-B4@google.com>
Date: Fri, 28 Feb 2025 16:09:41 -0800
From: Namhyung Kim <namhyung@...nel.org>
To: Thomas Falcon <thomas.falcon@...el.com>
Cc: linux-perf-users@...r.kernel.org, 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>, Ian Rogers <irogers@...gle.com>,
	Adrian Hunter <adrian.hunter@...el.com>,
	Kan Liang <kan.liang@...ux.intel.com>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] perf stat: Fix uniquify for hybrid systems

Hello,

On Fri, Feb 28, 2025 at 01:53:51PM -0600, Thomas Falcon wrote:
> Currently, perf stat is omitting the pmu name for legacy events
> on hybrid systems. git bisect indicated commit 357b965deba9 as the cause:
> 
> Bisecting: 0 revisions left to test after this (roughly 0 steps)
> [357b965deba9fb71467413e473764ec4e1694d8d] perf stat: Changes to event
> name uniquification
> 
> Include an additional check for hybrid architectures when determining
> whether to uniquify legacy events.
> 
> Before:
> 
> $ sudo ./perf stat -e cycles -a sleep 1
> 
>  Performance counter stats for 'system wide':
> 
>        173,903,751      cycles
>        666,423,950      cycles
> 
>        1.006615048 seconds time elapsed
> 
> After:
> 
> $ sudo ./perf stat -e cycles -a sleep 1
> 
>  Performance counter stats for 'system wide':
> 
>        841,496,603      cpu_atom/cycles/
>      3,308,929,412      cpu_core/cycles/
> 
>        1.002483283 seconds time elapsed
> 
> Fixes: 357b965deba9 ("perf stat: Changes to event name uniquification")
> Signed-off-by: Thomas Falcon <thomas.falcon@...el.com>

Thanks for the fix, but there's a similar patch in the list.
Please take a look.

https://lore.kernel.org/r/20250226145526.632380-1-james.clark@linaro.org

Thanks,
Namhyung

> ---
>  tools/perf/util/stat-display.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/perf/util/stat-display.c b/tools/perf/util/stat-display.c
> index e65c7e9f15d1..df9f68080ec9 100644
> --- a/tools/perf/util/stat-display.c
> +++ b/tools/perf/util/stat-display.c
> @@ -1676,6 +1676,7 @@ static bool evlist__disable_uniquify(const struct evlist *evlist)
>  
>  static void evsel__set_needs_uniquify(struct evsel *counter, const struct perf_stat_config *config)
>  {
> +	bool hybrid = (!config->hybrid_merge && evsel__is_hybrid(counter));
>  	struct evsel *evsel;
>  
>  	if (counter->merged_stat) {
> @@ -1688,7 +1689,8 @@ static void evsel__set_needs_uniquify(struct evsel *counter, const struct perf_s
>  		return;
>  	}
>  
> -	if  (counter->core.attr.type < PERF_TYPE_MAX && counter->core.attr.type != PERF_TYPE_RAW) {
> +	if (!hybrid && counter->core.attr.type < PERF_TYPE_MAX &&
> +		counter->core.attr.type != PERF_TYPE_RAW) {
>  		/* Legacy event, don't uniquify. */
>  		return;
>  	}
> @@ -1705,7 +1707,7 @@ static void evsel__set_needs_uniquify(struct evsel *counter, const struct perf_s
>  		return;
>  	}
>  
> -	if (!config->hybrid_merge && evsel__is_hybrid(counter)) {
> +	if (hybrid) {
>  		/* Unique hybrid counters necessary. */
>  		counter->needs_uniquify = true;
>  		return;
> -- 
> 2.48.1
>