Em Fri, Nov 27, 2020 at 01:14:03PM +0900, Namhyung Kim escreveu:
> Currently perf stat shows some metrics (like IPC) for defined events.
> But when no aggregation mode is used (-A option), it shows incorrect
> values since it used a value from a different cpu.
>
> Before:
>
> $ perf stat -aA -e cycles,instructions sleep 1
>
> Performance counter stats for 'system wide':
>
> CPU0 116,057,380 cycles
> CPU1 86,084,722 cycles
> CPU2 99,423,125 cycles
> CPU3 98,272,994 cycles
> CPU0 53,369,217 instructions # 0.46 insn per cycle
> CPU1 33,378,058 instructions # 0.29 insn per cycle
> CPU2 58,150,086 instructions # 0.50 insn per cycle
> CPU3 40,029,703 instructions # 0.34 insn per cycle
>
> 1.001816971 seconds time elapsed
>
> So the IPC for CPU1 should be 0.38 (= 33,378,058 / 86,084,722)
> but it was 0.29 (= 33,378,058 / 116,057,380) and so on.
>
> After:
>
> $ perf stat -aA -e cycles,instructions sleep 1
>
> Performance counter stats for 'system wide':
>
> CPU0 109,621,384 cycles
> CPU1 159,026,454 cycles
> CPU2 99,460,366 cycles
> CPU3 124,144,142 cycles
> CPU0 44,396,706 instructions # 0.41 insn per cycle
> CPU1 120,195,425 instructions # 0.76 insn per cycle
> CPU2 44,763,978 instructions # 0.45 insn per cycle
> CPU3 69,049,079 instructions # 0.56 insn per cycle
>
> 1.001910444 seconds time elapsed
Thanks, applied, the new 'perf test' entry in 2/2 will be merged into
perf/core, as it isn't purely a fix,
- Arnaldo
> Reported-by: Sam Xi <xyz...@google.com>
> Fixes: 44d49a600259 ("perf stat: Support metrics in --per-core/socket mode")
> Reviewed-by: Andi Kleen <a...@linux.intel.com>
> Acked-by: Jiri Olsa <jo...@redhat.com>
> Signed-off-by: Namhyung Kim <namhy...@kernel.org>
> ---
> tools/perf/util/stat-display.c | 5 +----
> 1 file changed, 1 insertion(+), 4 deletions(-)
>
> diff --git a/tools/perf/util/stat-display.c b/tools/perf/util/stat-display.c
> index 4b57c0c07632..a963b5b8eb72 100644
> --- a/tools/perf/util/stat-display.c
> +++ b/tools/perf/util/stat-display.c
> @@ -324,13 +324,10 @@ static int first_shadow_cpu(struct perf_stat_config
> *config,
> struct evlist *evlist = evsel->evlist;
> int i;
>
> - if (!config->aggr_get_id)
> - return 0;
> -
> if (config->aggr_mode == AGGR_NONE)
> return id;
>
> - if (config->aggr_mode == AGGR_GLOBAL)
> + if (!config->aggr_get_id)
> return 0;
>
> for (i = 0; i < evsel__nr_cpus(evsel); i++) {
> --
> 2.29.2.454.gaff20da3a2-goog
>
--
- Arnaldo
