linux-kernel - Re: [PATCH] perf, tools, stat: Force C numeric locale for CSV mode

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Message-ID: <20160105212839.GL15533@two.firstfloor.org>
Date:	Tue, 5 Jan 2016 22:28:39 +0100
From:	Andi Kleen <andi@...stfloor.org>
To:	Arnaldo Carvalho de Melo <acme@...nel.org>
Cc:	Andi Kleen <andi@...stfloor.org>, Jiri Olsa <jolsa@...hat.com>,
	jolsa@...nel.org, mingo@...nel.org, linux-kernel@...r.kernel.org,
	Andi Kleen <ak@...ux.intel.com>
Subject: Re: [PATCH] perf, tools, stat: Force C numeric locale for CSV mode

On Tue, Jan 05, 2016 at 06:17:57PM -0300, Arnaldo Carvalho de Melo wrote:
> Em Tue, Jan 05, 2016 at 10:05:01PM +0100, Jiri Olsa escreveu:
> > On Tue, Jan 05, 2016 at 11:17:45AM -0800, Andi Kleen wrote:
> > > From: Andi Kleen <ak@...ux.intel.com>
> > > 
> > > Some locales print floating point numbers with a comma instead of a dot.
> > > This causes problems with CSV mode because it causes extra false CSV
> > > fields. Force the numeric locale to be always C in CSV mode.
> > > 
> > > Before:
> > > 
> > > $ LC_ALL=pl_PL.utf8  perf stat -x, true
> > > 0,399472,,task-clock,399472,100,00			<---- extra bogus field
> > > ...
> > > 
> > > After:
> > > $ LC_ALL=pl_PL.utf8  ./obj-perf/perf stat -x, true
> > > 0.338422,,task-clock,338422,100.00
> > > 
> > > Originally reported in https://github.com/andikleen/pmu-tools/issues/43
> > > 
> > > Signed-off-by: Andi Kleen <ak@...ux.intel.com>
> > 
> > Acked-by: Jiri Olsa <jolsa@...nel.org>
> 
> I wonder what is that other tools do when stumbling on this, i.e.
> some other tool output that produces values that have the CSV character
> in it...

Proper CSV supports escaping the separator by putting the whole field
into quotes. Unfortunately perf stat doesn't output proper CSV,
the event fields with commas are not quoted.

I usually work around it by using -x\; instead

But the , problem should be still fixed.

> 
> Completely disabling the configured locale seems too harsh to me, aren't
> people used to changing the csv char via some option like we have in
> 'perf stat':
> 
>     -x, --field-separator
> 
> when changing the locale from the default 'C' one? Hey, you even used it
> above, but you chose a CSV char that is used in this locale, oops ;-)

It's just for numbers (LC_NUMERIC), everything else is still localized.

-Andi
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