linux-kernel - Re: [PATCH] perf stat: Fix endless wait for child process

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Message-ID: <20190103124356.GA32598@kernel.org>
Date:   Thu, 3 Jan 2019 09:43:56 -0300
From:   Arnaldo Carvalho de Melo <acme@...nel.org>
To:     Jiri Olsa <jolsa@...hat.com>
Cc:     Jin Yao <yao.jin@...ux.intel.com>, jolsa@...nel.org,
        peterz@...radead.org, mingo@...hat.com,
        alexander.shishkin@...ux.intel.com, Linux-kernel@...r.kernel.org,
        ak@...ux.intel.com, kan.liang@...el.com, yao.jin@...el.com
Subject: Re: [PATCH] perf stat: Fix endless wait for child process

Em Thu, Jan 03, 2019 at 12:12:05PM +0100, Jiri Olsa escreveu:
> On Thu, Jan 03, 2019 at 03:40:45PM +0800, Jin Yao wrote:
> > We hit a perf stat issue by using following script.
> > 
> >   #!/bin/bash
> > 
> >   sleep 1000 &
> >   exec perf stat -a -e cycles -I1000 -- sleep 5
> > 
> > Since "perf stat" is launched by exec, so the "sleep 1000" would be
> > the child process of "perf stat". The wait4() will not return because
> > it's waiting for the child process "sleep 1000" to be end. So perf
> > stat doesn't return even 5s passed.
> > 
> > This patch lets the perf stat return when the specified child process
> > is end (in this case, specified child process is "sleep 5").
> > 
> > Signed-off-by: Jin Yao <yao.jin@...ux.intel.com>
> 
> Reviewed-by: Jiri Olsa <jolsa@...nel.org>

Thanks, tested and applied.

- Arnaldo