linux-kernel - Re: [PATCHv2 4/5] perf stat: Add -a as a default target

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Date:   Tue, 21 Feb 2017 10:34:26 -0300
From:   Arnaldo Carvalho de Melo <acme@...nel.org>
To:     Borislav Petkov <bp@...en8.de>
Cc:     Jiri Olsa <jolsa@...hat.com>, Jiri Olsa <jolsa@...nel.org>,
        David Ahern <dsahern@...il.com>,
        Namhyung Kim <namhyung@...nel.org>,
        Peter Zijlstra <a.p.zijlstra@...llo.nl>,
        lkml <linux-kernel@...r.kernel.org>,
        Ingo Molnar <mingo@...nel.org>
Subject: Re: [PATCHv2 4/5] perf stat: Add -a as a default target

Em Tue, Feb 21, 2017 at 12:20:28PM +0100, Borislav Petkov escreveu:
> On Tue, Feb 21, 2017 at 12:04:51PM +0100, Jiri Olsa wrote:
> > could you please test this change?
> 
> LGTM, thanks!

Only one remark about a misleading warning, that is not a warning, is an
error, as its mere presence prevents what was asked for from being
performed.
 
> $ ./perf stat -v -e amd_nb/event=0xe0,umask=0x1f/ sleep 1
> Using CPUID AuthenticAMD-21-2
> amd_nb/event=0xe0,umask=0x1f/: 249356 1002053637 1002053637
> 
>  Performance counter stats for 'system wide':
> 
>            249,356      amd_nb/event=0xe0,umask=0x1f/
> 
>        1.002080419 seconds time elapsed
> 
> $ ./perf stat -v -e amd_nb/event=0xe0,umask=0x1f/,cycles sleep 1
> Using CPUID AuthenticAMD-21-2
> Warning:
  ^^^^^^^
  ^^^^^^^
  Error:
  ^^^^^^^
  ^^^^^^^
> amd_nb/event=0xe0,umask=0x1f/ event is not supported by the kernel.
                                                                     in system wide mode.
                                                                     ^^^^^^^^^^^^^^^^^^^^
                                                                     ^^^^^^^^^^^^^^^^^^^^
                                                                     ^^^^^^^^^^^^^^^^^^^^

It _is_ supported by the kernel, and by the hardware, its just that it
is not supported in system wide mode, that BTW, in the case above, the
user doesn't even asked for (-a wasn't in the command line).

> failed to read counter amd_nb/event=0xe0,umask=0x1f/
> amd_nb/event=0xe0,umask=0x1f/: 0 0 0
> cycles: 1223719 815034 815034
> 
>  Performance counter stats for 'sleep 1':
> 
>    <not supported>      amd_nb/event=0xe0,umask=0x1f/
>          1,223,719      cycles
> 
>        1.001679931 seconds time elapsed
> 
> $ ./perf stat -v -e amd_nb/event=0xe0,umask=0x1f/,amd_nb/event=0xe1,umask=0x3/ sleep 1
> Using CPUID AuthenticAMD-21-2
> amd_nb/event=0xe0,umask=0x1f/: 262994 1001697720 1001697720
> amd_nb/event=0xe1,umask=0x3/: 0 1001701216 1001701216
> 
>  Performance counter stats for 'system wide':
> 
>            262,994      amd_nb/event=0xe0,umask=0x1f
>                  0      amd_nb/event=0xe1,umask=0x3/
> 
>        1.001718951 seconds time elapsed
> 
> $ ./perf stat -v -e amd_nb/event=0xe0,umask=0x1f/,amd_nb/event=0xe1,umask=0x3/,amd_nb/event=0xe2,umask=0x3/ sleep 1
> Using CPUID AuthenticAMD-21-2
> amd_nb/event=0xe0,umask=0x1f/: 203936 1001654831 1001654831
> amd_nb/event=0xe1,umask=0x3/: 0 1001657636 1001657636
> amd_nb/event=0xe2,umask=0x3/: 988016 1001657991 1001657991
> 
>  Performance counter stats for 'system wide':
> 
>            203,936      amd_nb/event=0xe0,umask=0x1f/
>                  0      amd_nb/event=0xe1,umask=0x3/
>            988,016      amd_nb/event=0xe2,umask=0x3/
> 
>        1.001681434 seconds time elapsed
> 
> $ ./perf stat -v -a -e amd_nb/event=0xe0,umask=0x1f/,amd_nb/event=0xe1,umask=0x3/,amd_nb/event=0xe2,umask=0x3/,cycles sleep 1
> Using CPUID AuthenticAMD-21-2
> amd_nb/event=0xe0,umask=0x1f/: 365803 1001738673 1001738673
> amd_nb/event=0xe1,umask=0x3/: 0 1001736790 1001736790
> amd_nb/event=0xe2,umask=0x3/: 1884159 1001731876 1001731876
> cycles: 156820391 8014227609 8014227609
> 
>  Performance counter stats for 'system wide':
> 
>            365,803      amd_nb/event=0xe0,umask=0x1f/
>                  0      amd_nb/event=0xe1,umask=0x3/
>          1,884,159      amd_nb/event=0xe2,umask=0x3/
>        156,820,391      cycles
> 
>        1.001963906 seconds time elapsed
> 
> -- 
> Regards/Gruss,
>     Boris.
> 
> Good mailing practices for 400: avoid top-posting and trim the reply.