Re: [PATCH 07/11] perf, tools: Collapse identically named events in perf stat

[Jiri Olsa]

On Tue, Jan 03, 2017 at 07:08:29AM -0800, Andi Kleen wrote:
> From: Andi Kleen <ak@xxxxxxxxxxxxxxx>
> 
> The uncore PMU has a lot of duplicated PMUs for different subsystems.
> When expanding an uncore alias we usually end up with a large
> number of identically named aliases, which makes perf stat
> output difficult to read.
> 
> Automatically sum them up in perf stat, unless --no-merge is specified.
> 
> This can be default because only the uncores generally have duplicated
> aliases. Other PMUs have unique names.
> 
> Before:
> 
> % perf stat --no-merge -a  -e unc_c_llc_lookup.any sleep 1
> 
>  Performance counter stats for 'system wide':
> 
>            694,976 Bytes unc_c_llc_lookup.any
>            706,304 Bytes unc_c_llc_lookup.any
>            956,608 Bytes unc_c_llc_lookup.any
>            782,720 Bytes unc_c_llc_lookup.any
>            605,696 Bytes unc_c_llc_lookup.any
>            442,816 Bytes unc_c_llc_lookup.any
>            659,328 Bytes unc_c_llc_lookup.any
>            509,312 Bytes unc_c_llc_lookup.any
>            263,936 Bytes unc_c_llc_lookup.any
>            592,448 Bytes unc_c_llc_lookup.any
>            672,448 Bytes unc_c_llc_lookup.any
>            608,640 Bytes unc_c_llc_lookup.any
>            641,024 Bytes unc_c_llc_lookup.any
>            856,896 Bytes unc_c_llc_lookup.any
>            808,832 Bytes unc_c_llc_lookup.any
>            684,864 Bytes unc_c_llc_lookup.any
>            710,464 Bytes unc_c_llc_lookup.any
>            538,304 Bytes unc_c_llc_lookup.any
> 
>        1.002577660 seconds time elapsed
> 
> After:
> 
> % perf stat  -a  -e unc_c_llc_lookup.any sleep 1
> 
>  Performance counter stats for 'system wide':
> 
>          2,685,120 Bytes unc_c_llc_lookup.any
> 
>        1.002648032 seconds time elapsed


if one of them is not supported, we get wrong output:


[jolsa@krava perf]$ sudo ./perf stat --no-merge -a  -e clockticks sleep 1

 Performance counter stats for 'system wide':

   <not supported>      clockticks                                                  
         4,925,158      clockticks                                                  

       1.000982200 seconds time elapsed

[jolsa@krava perf]$ sudo ./perf stat  -a  -e clockticks sleep 1

 Performance counter stats for 'system wide':

   <not supported>      clockticks                                                  

       1.000850195 seconds time elapsed

jirka