[PATCH v4 03/48] perf stat: Correct aggregation CPU map

[John Garry]

On 05/01/2022 06:13, Ian Rogers wrote:
> Switch the perf_cpu_map in aggr_update_shadow from
> the evlist to the counter's cpu map, so the index is appropriate. This
> addresses a problem where uncore counts, with a cpumap like:
> $ cat /sys/devices/uncore_imc_0/cpumask
> 0,18
> Don't aggregate counts in CPUs based on the index of those values in the
> cpumap (0 and 1) but on the actual CPU (0 and 18). Thereby correcting
> metric calculations in per-socket mode for counters without a full
> cpumask.
> 
> On a SkylakeX with a tweaked DRAM_BW_Use metric, to remove unnecessary
> scaling, this gives:
> 
> Before:
> $ /perf stat --per-socket -M DRAM_BW_Use -I 1000
>       1.001102293 S0        1              27.01 MiB  uncore_imc/cas_count_write/ #   103.00 DRAM_BW_Use
>       1.001102293 S0        1              30.22 MiB  uncore_imc/cas_count_read/
>       1.001102293 S0        1      1,001,102,293 ns   duration_time
>       1.001102293 S1        1              20.10 MiB  uncore_imc/cas_count_write/ #     0.00 DRAM_BW_Use
>       1.001102293 S1        1              32.74 MiB  uncore_imc/cas_count_read/
>       1.001102293 S1        0      <not counted> ns   duration_time
>       2.003517973 S0        1              83.04 MiB  uncore_imc/cas_count_write/ #   920.00 DRAM_BW_Use
>       2.003517973 S0        1             145.95 MiB  uncore_imc/cas_count_read/
>       2.003517973 S0        1      1,002,415,680 ns   duration_time
>       2.003517973 S1        1             302.45 MiB  uncore_imc/cas_count_write/ #     0.00 DRAM_BW_Use
>       2.003517973 S1        1             290.99 MiB  uncore_imc/cas_count_read/
>       2.003517973 S1        0      <not counted> ns   duration_time
> 
> After:
> $ perf stat --per-socket -M DRAM_BW_Use -I 1000
>       1.001080840 S0        1              24.96 MiB  uncore_imc/cas_count_write/ #    54.00 DRAM_BW_Use
>       1.001080840 S0        1              33.64 MiB  uncore_imc/cas_count_read/
>       1.001080840 S0        1      1,001,080,840 ns   duration_time
>       1.001080840 S1        1              42.43 MiB  uncore_imc/cas_count_write/ #    84.00 DRAM_BW_Use
>       1.001080840 S1        1              47.05 MiB  uncore_imc/cas_count_read/
>       1.001080840 S1        0      <not counted> ns   duration_time
> 
> Signed-off-by: Ian Rogers<irogers at google.com>

Tested-by: John Garry <john.garry at huawei.com>