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: Fri, 28 Jun 2013 07:46:23 -0600 [thread overview]
Message-ID: <51CD93AF.3060908@gmail.com> (raw)
In-Reply-To: <51CD3187.5050603@intel.com>
On 6/28/13 12:47 AM, Adrian Hunter wrote:
>> 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.
>
> That means renaming ppid to ptid. Do you want to do that?
Don't lose information, so if you want the process id add ppid and ptid.
I like knowing the exact thread.
>
> Isn't it possible that the parent could exit and the pid or tid be re-used
> for another process? In that case, to reliable identify the parent a
> pointer to its struct thread would be needed. i.e.
>
> diff --git a/tools/perf/util/thread.h b/tools/perf/util/thread.h
> --- a/tools/perf/util/thread.h
> +++ b/tools/perf/util/thread.h
> @@ -14,6 +14,7 @@ struct thread {
> struct map_groups mg;
> pid_t pid_; /* Not all tools update this */
> pid_t tid;
> - pid_t ppid;
> + struct thread *parent;
> char shortname[3];
> bool comm_set;
>
> However that means tracking the lifetime of 'parent' to ensure that it is
> not left dangling.
>
> Do you want to do that?
No, I do not think we want to save pointers to other thread structs. We
actually need to be able to clean up the dead_threads list for long
running sessions and dangling pointers would add to the problem.
David
prev parent reply other threads:[~2013-06-28 13:46 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-27 7:54 [PATCH V2 00/15] perf tools: some fixes and tweaks Adrian Hunter
2013-06-27 7:54 ` [PATCH V2 01/15] perf tools: remove unused parameter Adrian Hunter
2013-06-27 7:54 ` [PATCH V2 02/15] perf tools: fix missing tool parameter Adrian Hunter
2013-06-27 7:54 ` [PATCH V2 03/15] perf tools: fix missing 'finished_round' Adrian Hunter
2013-06-27 7:54 ` [PATCH V2 04/15] perf tools: fix parse_events_terms() segfault on error path Adrian Hunter
2013-06-27 7:54 ` [PATCH V2 05/15] perf tools: fix new_term() missing free " Adrian Hunter
2013-06-27 7:54 ` [PATCH V2 06/15] perf tools: fix parse_events_terms() freeing local variable " Adrian Hunter
2013-06-27 16:13 ` David Ahern
2013-06-28 6:32 ` Adrian Hunter
2013-06-28 13:41 ` David Ahern
2013-06-28 13:57 ` Jiri Olsa
2013-06-27 7:54 ` [PATCH V2 07/15] perf tools: add const specifier to perf_pmu__find name parameter Adrian Hunter
2013-06-27 7:55 ` [PATCH V2 08/15] perf tools: tidy duplicated munmap code Adrian Hunter
2013-06-27 7:55 ` [PATCH V2 09/15] perf tools: validate perf event header size Adrian Hunter
2013-06-27 7:55 ` [PATCH V2 10/15] perf tools: add debug prints Adrian Hunter
2013-06-27 7:55 ` [PATCH V2 11/15] perf tools: fix symbol_conf.nr_events Adrian Hunter
2013-06-27 7:55 ` [PATCH V2 12/15] perf tools: allow non-matching sample types Adrian Hunter
2013-06-27 16:39 ` David Ahern
2013-07-01 9:32 ` Adrian Hunter
2013-07-01 18:53 ` David Ahern
2013-07-01 19:10 ` Stephane Eranian
2013-07-02 6:58 ` Adrian Hunter
2013-07-03 6:40 ` Stephane Eranian
2013-07-02 7:09 ` Adrian Hunter
2013-07-03 6:44 ` Stephane Eranian
2013-08-26 18:54 ` Arnaldo Carvalho de Melo
2013-06-27 7:55 ` [PATCH V2 13/15] perf tools: struct thread has a tid not a pid Adrian Hunter
2013-06-27 7:55 ` [PATCH V2 14/15] perf tools: add pid to struct thread Adrian Hunter
2013-06-27 16:52 ` David Ahern
2013-06-27 7:55 ` [PATCH V2 15/15] perf tools: fix ppid in thread__fork() Adrian Hunter
2013-06-27 16:57 ` David Ahern
2013-06-28 6:47 ` Adrian Hunter
2013-06-28 13:46 ` David Ahern [this message]
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