linux-kernel - Re: [PATCH 05/11] perf stat: Check existence of frontend/backed stalled cycles

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Date:	Thu, 3 Mar 2016 09:50:27 -0300
From:	Arnaldo Carvalho de Melo <acme@...hat.com>
To:	Ingo Molnar <mingo@...nel.org>
Cc:	Arnaldo Carvalho de Melo <acme@...nel.org>,
	linux-kernel@...r.kernel.org, Andi Kleen <ak@...ux.intel.com>,
	Stephane Eranian <eranian@...gle.com>
Subject: Re: [PATCH 05/11] perf stat: Check existence of frontend/backed
 stalled cycles

Em Thu, Mar 03, 2016 at 09:49:00AM -0300, Arnaldo Carvalho de Melo escreveu:
> Em Thu, Mar 03, 2016 at 09:28:18AM +0100, Ingo Molnar escreveu:
> > 
> > * Arnaldo Carvalho de Melo <acme@...nel.org> wrote:
> > 
> > > Before:
> > > 
> > >   $ perf stat ls
> > >   a.patch
> > > 
> > >   Performance counter stats for 'ls':
> > > 
> > >          0.822067 task-clock (msec)   #   0.873 CPUs utilized   (82.26%)
> > >                 0 context-switches    #   0.000 K/sec           (82.26%)
> > >                 0 cpu-migrations      #   0.000 K/sec           (82.26%)
> > >               125 page-faults         #   0.152 M/sec           (82.26%)
> > >         2,516,127 cycles              #   3.061 GHz             (82.84%)
> > >   <not supported> stalled-cycles-frontend
> > >   <not supported> stalled-cycles-backend
> > >         2,430,467 instructions        #   0.97  insn per cycle  (82.84%)
> > >           486,235 branches            # 591.479 M/sec           (82.84%)
> > >            18,389 branch-misses       #   3.78% of all branches (82.84%)
> > > 
> > >       0.000941536 seconds time elapsed
> > >   $
> > > 
> > > After:
> > > 
> > >   $ perf stat ls
> > >   a.patch
> > > 
> > >   Performance counter stats for 'ls':
> > > 
> > >          0.824919 task-clock (msec)   #   0.893 CPUs utilized   (85.47%)
> > >                 0 context-switches    #   0.000 K/sec           (85.47%)
> > >                 0 cpu-migrations      #   0.000 K/sec           (85.47%)
> > >               124 page-faults         #   0.150 M/sec           (85.47%)
> > >           2521790 cycles              #   3.057 GHz             (86.15%)
> > >           2364913 instructions        #   0.94  insn per cycle  (86.15%)
> > >            471970 branches            # 572.141 M/sec           (86.15%)
> > >             16935 branch-misses       #   3.59% of all branches (86.15%)
> > > 
> > >       0.000923397 seconds time elapsed
> > >   $
> > 
> > Btw., the output format regression is visible in this changelog already...
> 
> Right, uf, should've pick this up at this point :-\
> 
> Will go back and fix it up, so that we don't introduce a regression.

Well, in this case its not a matter of fixing the patch, but making sure
that Jiri's locale pmu parsing fix comes before this patch, so inserting
a patch, will do.

- Arnaldo