Date: Mon, 11 May 2015 18:29:28 +0100
From: Will Deacon <will.deacon@arm.com>
To: "acme@redhat.com" <acme@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>, David Ahern <david.ahern@oracle.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Mark Rutland <Mark.Rutland@arm.com>,
        "jolsa@kernel.org" <jolsa@kernel.org>,
        "namhyung@kernel.org" <namhyung@kernel.org>
Subject: Re: arm/arm64 perf build issue with mainline
Message-ID: <20150511172928.GF4795@arm.com>
References: <20150423112916.GF1652@arm.com>
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 <20150511082120.GA13145@gmail.com>
 <20150511123117.GD4795@arm.com>
 <20150511123304.GA28716@gmail.com>
 <20150511155814.GA2724@redhat.com>
 <20150511155958.GB2724@redhat.com>
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On Mon, May 11, 2015 at 04:59:58PM +0100, acme@redhat.com wrote:
> Em Mon, May 11, 2015 at 12:58:14PM -0300, acme@redhat.com escreveu:
> > Em Mon, May 11, 2015 at 02:33:04PM +0200, Ingo Molnar escreveu:
> > > > That was already proposed here (as part of the fallback from getconf):
> > > > 
> > > >   https://lkml.kernel.org/r/20150427190356.GD474@krava.redhat.com
> > > > 
> > > > but I'm not sure what happened to the patch.
> > > 
> > > Sending out the latest/best version as a reminder for Arnaldo will 
> > > sure help it along.
> > > 
> > > Acked-by: Ingo Molnar <mingo@kernel.org>
> > 
> > IIRC it was merged already, lemme check...
> 
> Yes, only for perf/core:

Ah, that explains why I couldn't see it in my tree. Could we get it in
for 4.1 please, as this is a regression for arm/arm64 (where the
auto-detection used to work fine)?

Cheers,

Will

> 
> [acme@zoo linux]$ git show 762abdc0c6c013425958cd9f5105f4e32268d434
> commit 762abdc0c6c013425958cd9f5105f4e32268d434
> Author: Will Deacon <will.deacon@arm.com>
> Date:   Thu Apr 23 15:00:16 2015 +0100
> 
>     perf tools: Use getconf to determine number of online CPUs
>     
>     Parsing /proc/cpuinfo is a fiddly, arch-dependent business and a recent
>     change to get it working for Sparc broke arm and arm64 platforms.
>     
>     Use sysconf to determine the number of online CPUs only parsing
>     /proc/cpuinfo when sysconf is not available.
>     
>     Signed-off-by: Will Deacon <will.deacon@arm.com>
>     Acked-by: Jiri Olsa <jolsa@kernel.org>
>     Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
>     Cc: David Ahern <david.ahern@oracle.com>
>     Cc: Mark Rutland <Mark.Rutland@arm.com>
>     Cc: Namhyung Kim <namhyung@kernel.org>
>     Link: http://lkml.kernel.org/r/20150423140454.GJ1652@arm.com
>     [ Made it fall back to parsing /proc when getconf not found ]
>     Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
> 
> diff --git a/tools/perf/Makefile b/tools/perf/Makefile
> index c699dc35eef9..d31a7bbd7cee 100644
> --- a/tools/perf/Makefile
> +++ b/tools/perf/Makefile
> @@ -24,7 +24,7 @@ unexport MAKEFLAGS
>  # (To override it, run 'make JOBS=1' and similar.)
>  #
>  ifeq ($(JOBS),)
> -  JOBS := $(shell egrep -c '^processor|^CPU' /proc/cpuinfo 2>/dev/null)
> +  JOBS := $(shell (getconf _NPROCESSORS_ONLN || egrep -c '^processor|^CPU[0-9]' /proc/cpuinfo) 2>/dev/null)
>    ifeq ($(JOBS),0)
>      JOBS := 1
>    endif
> [acme@zoo linux]$ 
> 
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