Re: [PATCH v3] perf stat: Show percore counts in per CPU output

["Jin, Yao" <yao.jin@linux.intel.com>]

On 2/13/2020 9:20 PM, Ravi Bangoria wrote:
> Hi Jin,
> 
> On 2/13/20 12:45 PM, Jin Yao wrote:
>> With this patch, for example,
>>
>>   # perf stat -e cpu/event=cpu-cycles,percore/ -a -A 
>> --percore-show-thread  -- sleep 1
>>
>>    Performance counter stats for 'system wide':
>>
>>   CPU0               2,453,061      cpu/event=cpu-cycles,percore/
>>   CPU1               1,823,921      cpu/event=cpu-cycles,percore/
>>   CPU2               1,383,166      cpu/event=cpu-cycles,percore/
>>   CPU3               1,102,652      cpu/event=cpu-cycles,percore/
>>   CPU4               2,453,061      cpu/event=cpu-cycles,percore/
>>   CPU5               1,823,921      cpu/event=cpu-cycles,percore/
>>   CPU6               1,383,166      cpu/event=cpu-cycles,percore/
>>   CPU7               1,102,652      cpu/event=cpu-cycles,percore/
>>
>> We can see counts are duplicated in CPU pairs
>> (CPU0/CPU4, CPU1/CPU5, CPU2/CPU6, CPU3/CPU7).
>>
> 
> I was trying this patch and I am getting bit weird results when any cpu
> is offline. Ex,
> 
>    $ lscpu | grep list
>    On-line CPU(s) list:             0-4,6,7
>    Off-line CPU(s) list:            5
> 
>    $ sudo ./perf stat -e cpu/event=cpu-cycles,percore/ -a -A 
> --percore-show-thread -vv -- sleep 1
>      ...
>    cpu/event=cpu-cycles,percore/: 0: 23746491 1001189836 1001189836
>    cpu/event=cpu-cycles,percore/: 1: 19802666 1001291299 1001291299
>    cpu/event=cpu-cycles,percore/: 2: 24211983 1001394318 1001394318
>    cpu/event=cpu-cycles,percore/: 3: 54051396 1001516816 1001516816
>    cpu/event=cpu-cycles,percore/: 4: 6378825 1001064048 1001064048
>    cpu/event=cpu-cycles,percore/: 5: 21299840 1001166297 1001166297
>    cpu/event=cpu-cycles,percore/: 6: 13075410 1001274535 1001274535
>     Performance counter stats for 'system wide':
>    CPU0              30,125,316      cpu/event=cpu-cycles,percore/
>    CPU1              19,802,666      cpu/event=cpu-cycles,percore/
>    CPU2              45,511,823      cpu/event=cpu-cycles,percore/
>    CPU3              67,126,806      cpu/event=cpu-cycles,percore/
>    CPU4              30,125,316      cpu/event=cpu-cycles,percore/
>    CPU7              67,126,806      cpu/event=cpu-cycles,percore/
>    CPU0              30,125,316      cpu/event=cpu-cycles,percore/
>           1.001918764 seconds time elapsed
> 
> I see proper result without --percore-show-thread:
> 
>    $ sudo ./perf stat -e cpu/event=cpu-cycles,percore/ -a -A -vv -- sleep 1
>      ...
>    cpu/event=cpu-cycles,percore/: 0: 11676414 1001190709 1001190709
>    cpu/event=cpu-cycles,percore/: 1: 39119617 1001291459 1001291459
>    cpu/event=cpu-cycles,percore/: 2: 41821512 1001391158 1001391158
>    cpu/event=cpu-cycles,percore/: 3: 46853730 1001492799 1001492799
>    cpu/event=cpu-cycles,percore/: 4: 14448274 1001095948 1001095948
>    cpu/event=cpu-cycles,percore/: 5: 42238217 1001191187 1001191187
>    cpu/event=cpu-cycles,percore/: 6: 33129641 1001292072 1001292072
>     Performance counter stats for 'system wide':
>    S0-D0-C0             26,124,688      cpu/event=cpu-cycles,percore/
>    S0-D0-C1             39,119,617      cpu/event=cpu-cycles,percore/
>    S0-D0-C2             84,059,729      cpu/event=cpu-cycles,percore/
>    S0-D0-C3             79,983,371      cpu/event=cpu-cycles,percore/
>           1.001961563 seconds time elapsed
> 
> [...]
> 

Thanks so much for reporting this issue!

It looks I should use the cpu idx in print_percore_thread. I can't use 
the cpu value. I have a fix:

diff --git a/tools/perf/util/stat-display.c b/tools/perf/util/stat-display.c
index 7eb3643a97ae..d89cb0da90f8 100644
--- a/tools/perf/util/stat-display.c
+++ b/tools/perf/util/stat-display.c
@@ -1149,13 +1149,11 @@ static void print_footer(struct perf_stat_config 
*config)
  static void print_percore_thread(struct perf_stat_config *config,
                                  struct evsel *counter, char *prefix)
  {
-       int cpu, s, s2, id;
+       int s, s2, id;
         bool first = true;

         for (int i = 0; i < perf_evsel__nr_cpus(counter); i++) {
-               cpu = perf_cpu_map__cpu(evsel__cpus(counter), i);
-               s2 = config->aggr_get_id(config, evsel__cpus(counter), cpu);
-
+               s2 = config->aggr_get_id(config, evsel__cpus(counter), i);
                 for (s = 0; s < config->aggr_map->nr; s++) {
                         id = config->aggr_map->map[s];
                         if (s2 == id)
@@ -1164,7 +1162,7 @@ static void print_percore_thread(struct 
perf_stat_config *config,

                 print_counter_aggrdata(config, counter, s,
                                        prefix, false,
-                                      &first, cpu);
+                                      &first, i);
         }
  }

With this fix, my test log:

root@kbl:~# perf stat -e cpu/event=cpu-cycles,percore/ -a -A 
--percore-show-thread -- sleep 1

  Performance counter stats for 'system wide':

CPU0                 386,355      cpu/event=cpu-cycles,percore/
CPU1                 538,325      cpu/event=cpu-cycles,percore/
CPU2                 900,263      cpu/event=cpu-cycles,percore/
CPU3               1,871,488      cpu/event=cpu-cycles,percore/
CPU4                 386,355      cpu/event=cpu-cycles,percore/
CPU6                 900,263      cpu/event=cpu-cycles,percore/
CPU7               1,871,488      cpu/event=cpu-cycles,percore/

        1.001476492 seconds time elapsed

Once I online all CPUs, the result is:

root@kbl:~# perf stat -e cpu/event=cpu-cycles,percore/ -a -A 
--percore-show-thread -- sleep 1

  Performance counter stats for 'system wide':

CPU0               1,371,762      cpu/event=cpu-cycles,percore/
CPU1                 827,386      cpu/event=cpu-cycles,percore/
CPU2                 309,934      cpu/event=cpu-cycles,percore/
CPU3               5,043,596      cpu/event=cpu-cycles,percore/
CPU4               1,371,762      cpu/event=cpu-cycles,percore/
CPU5                 827,386      cpu/event=cpu-cycles,percore/
CPU6                 309,934      cpu/event=cpu-cycles,percore/
CPU7               5,043,596      cpu/event=cpu-cycles,percore/

        1.001535000 seconds time elapsed

>> +--percore-show-thread::
>> +The event modifier "percore" has supported to sum up the event counts
>> +for all hardware threads in a core and show the counts per core.
>> +
>> +This option with event modifier "percore" enabled also sums up the event
>> +counts for all hardware threads in a core but show the sum counts per
>> +hardware thread. This is essentially a replacement for the any bit and
>> +convenient for posting process.
> 
> s/posting process/post processing/ ? :)
> 

OK, thanks!

Thanks
Jin Yao

> Ravi
>