Re: 'perf stat --repeat N' oddity/regression

From: Arnaldo Carvalho de Melo
Date: Mon Jan 25 2016 - 14:43:45 EST


Em Mon, Jan 25, 2016 at 07:35:11PM +0100, Ingo Molnar escreveu:
>
> So it appears it broke somewhere between v4.0 and v4.1, as the v4.0 install
> displays:
>
> 16,244,802,268 instructions ( +- 23.01% )
>
> 2.108676769 seconds time elapsed ( +- 0.86% )
>
>
> [a few minutes later]
>
> Bisected it down to:

Mel Gorman reported this and Jiri provided a patch that Mel tested and
verified that it fixed, checking where it is sitting now...

- Arnaldo

> 106a94a0f8c207ef4113ce7e32f34a00b3b174e7 is the first bad commit
> commit 106a94a0f8c207ef4113ce7e32f34a00b3b174e7
> Author: Jiri Olsa <jolsa@xxxxxxxxxx>
> Date: Fri Jun 26 11:29:19 2015 +0200
>
> perf stat: Introduce read_counters function
>
> So this look like to be a regression.
>
> Thanks,
>
> Ingo