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Message-ID: <aedabebd-dad1-4b2b-93d7-e2d9884bdaf7@linux.intel.com>
Date: Tue, 13 Aug 2024 16:06:05 -0400
From: "Liang, Kan" <kan.liang@...ux.intel.com>
To: Arnaldo Carvalho de Melo <acme@...nel.org>
Cc: namhyung@...nel.org, irogers@...gle.com, peterz@...radead.org,
mingo@...nel.org, linux-kernel@...r.kernel.org,
linux-perf-users@...r.kernel.org, adrian.hunter@...el.com,
ak@...ux.intel.com, eranian@...gle.com
Subject: Re: [PATCH V3 1/9] perf report: Fix --total-cycles --stdio output
error
On 2024-08-13 2:44 p.m., Arnaldo Carvalho de Melo wrote:
> On Tue, Aug 13, 2024 at 09:02:00AM -0700, kan.liang@...ux.intel.com wrote:
>> From: Kan Liang <kan.liang@...ux.intel.com>
>>
>> The --total-cycles may output wrong information with the --stdio.
>
> Hey, I tried --total-cycles with --group but that didn't work, do you
> think that would make sense?
The current implementation doesn't handle the symbol_conf.event_group
for the tui mode.
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/tools/perf/builtin-report.c#n543
I will send a separate patch to fix it and make it consistent.
Thanks,
Kan
>
> Anyway, all applied, now testing and reviewing the changes,
>
> thanks!
>
> - Arnaldo
>
>> For example,
>> perf record -e "{cycles,instructions}",cache-misses -b sleep 1
>> perf report --total-cycles --stdio
>>
>> The total cycles output of {cycles,instructions} and cache-misses are
>> almost the same.
>>
>> # Samples: 938 of events 'anon group { cycles, instructions }'
>> # Event count (approx.): 938
>> #
>> # Sampled Cycles% Sampled Cycles Avg Cycles% Avg Cycles
>> # ............... .............. ........... ..........
>> ..................................................>
>> #
>> 11.19% 2.6K 0.10% 21
>> [perf_iterate_ctx+48 -> >
>> 5.79% 1.4K 0.45% 97
>> [__intel_pmu_enable_all.constprop.0+80 -> __intel_>
>> 5.11% 1.2K 0.33% 71
>> [native_write_msr+0 ->>
>>
>> # Samples: 293 of event 'cache-misses'
>> # Event count (approx.): 293
>> #
>> # Sampled Cycles% Sampled Cycles Avg Cycles% Avg Cycles
>> [>
>> # ............... .............. ........... ..........
>> ..................................................>
>> #
>> 11.19% 2.6K 0.13% 21
>> [perf_iterate_ctx+48 -> >
>> 5.79% 1.4K 0.59% 97
>> [__intel_pmu_enable_all.constprop.0+80 -> __intel_>
>> 5.11% 1.2K 0.43% 71
>> [native_write_msr+0 ->>
>>
>> With the symbol_conf.event_group, the perf report should only report the
>> block information of the leader event in a group.
>> However, the current implementation retrieves the next event's block
>> information, rather than the next group leader's block information.
>>
>> Make sure the index is updated even if the event is skipped.
>>
>> With the patch,
>>
>> # Samples: 293 of event 'cache-misses'
>> # Event count (approx.): 293
>> #
>> # Sampled Cycles% Sampled Cycles Avg Cycles% Avg Cycles
>> [>
>> # ............... .............. ........... ..........
>> ..................................................>
>> #
>> 37.98% 9.0K 4.05% 299
>> [perf_event_addr_filters_exec+0 -> perf_event_a>
>> 11.19% 2.6K 0.28% 21
>> [perf_iterate_ctx+48 -> >
>> 5.79% 1.4K 1.32% 97
>> [__intel_pmu_enable_all.constprop.0+80 -> __intel_>
>>
>> Fixes: 6f7164fa231a ("perf report: Sort by sampled cycles percent per block for stdio")
>> Acked-by: Namhyung Kim <namhyung@...nel.org>
>> Reviewed-by: Andi Kleen <ak@...ux.intel.com>
>> Signed-off-by: Kan Liang <kan.liang@...ux.intel.com>
>> ---
>> tools/perf/builtin-report.c | 3 ++-
>> 1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c
>> index dfb47fa85e5c..04b9a5c1bc7e 100644
>> --- a/tools/perf/builtin-report.c
>> +++ b/tools/perf/builtin-report.c
>> @@ -565,6 +565,7 @@ static int evlist__tty_browse_hists(struct evlist *evlist, struct report *rep, c
>> struct hists *hists = evsel__hists(pos);
>> const char *evname = evsel__name(pos);
>>
>> + i++;
>> if (symbol_conf.event_group && !evsel__is_group_leader(pos))
>> continue;
>>
>> @@ -574,7 +575,7 @@ static int evlist__tty_browse_hists(struct evlist *evlist, struct report *rep, c
>> hists__fprintf_nr_sample_events(hists, rep, evname, stdout);
>>
>> if (rep->total_cycles_mode) {
>> - report__browse_block_hists(&rep->block_reports[i++].hist,
>> + report__browse_block_hists(&rep->block_reports[i - 1].hist,
>> rep->min_percent, pos, NULL);
>> continue;
>> }
>> --
>> 2.38.1
>
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