Re: [PATCH V2 15/15] perf tools: fix ppid in thread__fork()

From: David Ahern <dsahern@gmail.com>
To: Adrian Hunter <adrian.hunter@intel.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>,
	linux-kernel@vger.kernel.org,
	Frederic Weisbecker <fweisbec@gmail.com>,
	Jiri Olsa <jolsa@redhat.com>, Mike Galbraith <efault@gmx.de>,
	Namhyung Kim <namhyung@gmail.com>,
	Paul Mackerras <paulus@samba.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Stephane Eranian <eranian@google.com>
Subject: Re: [PATCH V2 15/15] perf tools: fix ppid in thread__fork()
Date: Thu, 27 Jun 2013 10:57:58 -0600	[thread overview]
Message-ID: <51CC6F16.40004@gmail.com> (raw)
In-Reply-To: <1372319707-13892-16-git-send-email-adrian.hunter@intel.com>

On 6/27/13 1:55 AM, Adrian Hunter wrote:
> ppid should be assigned to the parents pid.  Note
> 'thread__fork()'s only caller 'machine__process_fork_event()'
> ensures that the parents pid is set.
>
> Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
> ---
>   tools/perf/util/thread.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c
> index e3d4a55..93f3eab 100644
> --- a/tools/perf/util/thread.c
> +++ b/tools/perf/util/thread.c
> @@ -85,7 +85,7 @@ int thread__fork(struct thread *self, struct thread *parent)
>   		if (map_groups__clone(&self->mg, &parent->mg, i) < 0)
>   			return -ENOMEM;
>
> -	self->ppid = parent->tid;
> +	self->ppid = parent->pid_;
>

knowledge of the specific thread within the parent that created the 
process can be valuable -- that's what we get now. This change drops 
that information. I'd prefer this stays at thread id -- or save the 
parent thread id in addition to the pid.

David