Re: [PATCH] perf, tools, stat: Avoid crash with --per-thread

From: Arnaldo Carvalho de Melo
Date: Wed Mar 02 2016 - 07:12:51 EST


Em Wed, Mar 02, 2016 at 07:36:59AM +0100, Jiri Olsa escreveu:
> On Tue, Mar 01, 2016 at 03:32:37PM -0800, Andi Kleen wrote:
> > From: Andi Kleen <ak@xxxxxxxxxxxxxxx>
> >
> > Bug fix:
> >
> > The earlier metrics changes broke --per-thread causing a segfault.
> > Handle this case correctly. We actually don't print metrics
> > in per thread mode, so using a 0 shadow CPU is fine.
>
> right, so --per-thread paths go through perf_stat__print_shadow_stats
> but never actually collect shadow data, so it does not print anything
>
> we would need somehow map each thread to the shadow cpu.. I'll try
> to come up with something.. however:
>
> Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>

Kept the ack for the previous commit ("Support metrics in
--per-core/socket mode")

> > Could be folded into
> > "perf, tools, stat: Support metrics in --per-core/socket mode"

And used 'git rebase --interactive' to 'fixup' this into it, i.e. do
what Andi suggested to avoid breaking the 'perf stat --per-thread'
bisection since this one hasn't been pushed to Ingo yet.

Thanks,

- Arnaldo