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

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Message-ID: <ba8dedbc-9a5f-4038-ad51-2b20baa6af65@linux.intel.com>
Date: Tue, 11 Mar 2025 08:45:20 +0800
From: "Mi, Dapeng" <dapeng1.mi@...ux.intel.com>
To: Namhyung Kim <namhyung@...nel.org>, Ian Rogers <irogers@...gle.com>
Cc: 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>, 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, Thomas Falcon <thomas.falcon@...el.com>
Subject: Re: [PATCH v2 4/5] perf x86 evlist: Update comments on topdown
 regrouping


On 3/11/2025 5:25 AM, Namhyung Kim wrote:
> Hello,
>
> On Thu, Mar 06, 2025 at 06:39:05PM -0800, Ian Rogers wrote:
>> 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>
> Dapeng, can I get your Signed-off-by here?
>
> Thanks,
> Namhyung
>
>> ---
>>  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

Yes, here is my SoB.

Signed-off-by: Dapeng Mi <dapeng1.mi@...ux.intel.com>

BTW, It seems there is a typo and missed the "not" word. It should be 
"slots event and metrics event are not in a group and not adjacent"

Thanks.


>> +	 *    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
>>