Re: [PATCH v3 2/7] perf metric: Event "Compat" value supports matching multiple identifiers

On 19/06/2023 09:59, Jing Zhang wrote:

quoted

Please verify running these metrics with 'perf stat', like 'perf stat -v -M slc_miss_rate'

Ok, it shows:
#./perf stat -v -M slc_miss_rate sleep 1

metric expr hnf_cache_miss / hnf_slc_sf_cache_access for slc_miss_rate
found event duration_time
found event hnf_slc_sf_cache_access

In the earlier RFC series you had 
tools/perf/pmu-events/arch/arm64/arm/cmn700/sys/cmn.json, which 
describes event hnf_slc_sf_cache_access

But that JSON is not in this series. Why is it not included?

The cmn kernel driver exposes event hnf_slc_sf_cache_access, but I did 
not think that perf tool metric code matches those events described in 
/bus/event_sourcs/devices/<PMU>/events

found event hnf_cache_miss
Parsing metric events '{hnf_slc_sf_cache_access/metric-id=hnf_slc_sf_cache_access/,hnf_cache_miss/metric-id=hnf_cache_miss/}:W,duration_time'
hnf_slc_sf_cache_access -> arm_cmn_0/type=0x5,eventid=0x2/
hnf_slc_sf_cache_access -> arm_cmn_1/type=0x5,eventid=0x2/
hnf_cache_miss -> arm_cmn_0/type=0x5,eventid=0x1/
hnf_cache_miss -> arm_cmn_1/type=0x5,eventid=0x1/
Control descriptor is not initialized
hnf_slc_sf_cache_access: 127615 1001344900 1001344900
hnf_cache_miss: 36829 1001344900 1001344900
hnf_slc_sf_cache_access: 131526 1001343540 1001343540
hnf_cache_miss: 40587 1001343540 1001343540
duration_time: 1001381687 1001381687 1001381687

  Performance counter stats for 'system wide':

            259,141      hnf_slc_sf_cache_access   #     29.9 %  slc_miss_rate
             77,416      hnf_cache_miss
      1,001,381,687 ns   duration_time

        1.001381687 seconds time elapsed



#./perf list
...
  arm_cmn_0/hnf_cache_miss/                          [Kernel PMU event]
  arm_cmn_0/hnf_slc_sf_cache_access/                 [Kernel PMU event]
...
  arm_cmn_1/hnf_cache_miss/                          [Kernel PMU event]
  arm_cmn_1/hnf_slc_sf_cache_access/                 [Kernel PMU event]
...

quoted

quoted

In the past, I always thought that the function of the alias was to explain the meaning of these events in the perf list.
Or maybe I'm missing something?

Event aliases do give the ability to describe the event in perf list. But we can also run them for 'perf stat', like:

./perf list uncore
List of pre-defined events (to be used in -e or -M):

   uncore_cbox_0/clockticks/                          [Kernel PMU event]
   uncore_cbox_1/clockticks/                          [Kernel PMU event]
   uncore_imc/data_reads/                             [Kernel PMU event]
   uncore_imc/data_writes/                            [Kernel PMU event]
   uncore_imc/gt_requests/                            [Kernel PMU event]
   uncore_imc/ia_requests/                            [Kernel PMU event]
   uncore_imc/io_requests/                            [Kernel PMU event]

uncore cache:
   unc_cbo_cache_lookup.any_es
        [L3 Lookup any request that access cache and found line in E or S-state. Unit: uncore_cbox]
...

sudo ./perf stat -v -e unc_cbo_cache_lookup.any_es
Using CPUID GenuineIntel-6-3D-4
unc_cbo_cache_lookup.any_es -> uncore_cbox_0/event=0x34,umask=0x86/
unc_cbo_cache_lookup.any_es -> uncore_cbox_1/event=0x34,umask=0x86/
Control descriptor is not initialized
^Cunc_cbo_cache_lookup.any_es: 14361103 1853372468 1853372468
unc_cbo_cache_lookup.any_es: 14322188 1853360415 1853360415

  Performance counter stats for 'system wide':

         14,361,103      unc_cbo_cache_lookup.any_es
         14,322,188      unc_cbo_cache_lookup.any_es

        1.853388227 seconds time elapsed

Ok, thanks. If I use events without a prefix, such as perf stat -e clockticks sleep 1, will this also work?

In this case, yes - it would work for uncore_cbox_0/clockticks/ and 
uncore_cbox_1/clockticks/

But you need to be careful to here - if another PMU has same event name, 
then it might also match.

Thanks,
John


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