linux-kernel - Re: [PATCH 1/2] perf map: synthesize maps only for thread group leader

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Date:   Tue, 7 Aug 2018 10:15:07 -0300
From:   Arnaldo Carvalho de Melo <acme@...nel.org>
To:     Jiri Olsa <jolsa@...hat.com>
Cc:     Konstantin Khlebnikov <khlebnikov@...dex-team.ru>,
        linux-kernel@...r.kernel.org,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Namhyung Kim <namhyung@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>
Subject: Re: [PATCH 1/2] perf map: synthesize maps only for thread group
 leader

Em Tue, Aug 07, 2018 at 02:43:34PM +0200, Jiri Olsa escreveu:
> On Tue, Aug 07, 2018 at 12:09:01PM +0300, Konstantin Khlebnikov wrote:
> > Threads share map_groups, all map events are merged into it.
> > 
> > Thus we could send mmaps only for thread group leader.
> > Otherwise it took ages to attach and record something from
> > processes with many vmas and threads.
> > 
> > Thread group leader could be already dead,
> > but it seems perf cannot handle this case anyway.
> 
> nice, could mention in the changelog that we actualy
> synthesize the group leader (if we found one) for the
> thread even if it's not present in the thread_map,
> so the process maps are always in data
> 
> Acked-by: Jiri Olsa <jolsa@...nel.org>

I'll add your notes, thanks everyone,

- Arnaldo