linux-kernel - Re: [PATCH] perf evsel: Correct clock unit to nanosecond

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Date:   Fri, 30 Nov 2018 22:21:40 +0800
From:   leo.yan@...aro.org
To:     Jiri Olsa <jolsa@...hat.com>
Cc:     Arnaldo Carvalho de Melo <acme@...nel.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Andi Kleen <ak@...ux.intel.com>, linux-kernel@...r.kernel.org,
        Daniel Thompson <daniel.thompson@...aro.org>
Subject: Re: [PATCH] perf evsel: Correct clock unit to nanosecond

On Fri, Nov 30, 2018 at 11:21:54AM +0100, Jiri Olsa wrote:
> On Fri, Nov 30, 2018 at 06:06:05PM +0800, Leo Yan wrote:
> > Since commit 0aa802a79469 ("perf stat: Get rid of extra clock display
> > function"), the cpu and task clock unit has been changed from
> > nanosecond value to millisecond value.  This introduces confusion for
> > CPU run time statistics, we can see in below flow the clock value is
> > scaled from nanosecond value to millisecond value; but this is
> > contradiction with statistics type 'STAT_NSECS', which always takes
> > clock as nanosecond unit.

[...]

> there was fix for this recently, could you please check
> if it's working for you:
>   6e269c85dcea perf stat: Fix shadow stats for clock events

Ah, I missed this patch ...

Yeah, I tested this patch and can confirm this patch fixes
this issue.

Thanks,
Leo Yan