All of lore.kernel.org
 help / color / mirror / Atom feed
From: David Ahern <dsahern@gmail.com>
To: Don Zickus <dzickus@redhat.com>,
	Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: linux-kernel@vger.kernel.org, Joe Mario <jmario@redhat.com>,
	Jiri Olsa <jolsa@redhat.com>
Subject: Re: [PATCH v2] perf tool: Fix ppid for synthesized fork events
Date: Fri, 27 Mar 2015 14:10:54 -0600	[thread overview]
Message-ID: <5515B94E.6020706@gmail.com> (raw)
In-Reply-To: <20150327194941.GG162412@redhat.com>

On 3/27/15 1:49 PM, Don Zickus wrote:
> diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c
> index 1c8fbc9..7ee3823 100644
> --- a/tools/perf/util/thread.c
> +++ b/tools/perf/util/thread.c
> @@ -187,6 +187,7 @@ static int thread__clone_map_groups(struct thread *thread,
>   	if (thread->pid_ == parent->pid_)
>   		return 0;

There's your answer ... the 2 lines above.

>
> +	printf("DON:\n");
>   	/* But this one is new process, copy maps. */
>   	for (i = 0; i < MAP__NR_TYPES; ++i)
>   		if (map_groups__clone(thread->mg, parent->mg, i) < 0)
>
> before David's patch, we do _not_ see any DON markers.  After David's patch
> we see a 1:1 match of DON markers to the number of threads currently running
> in the system.

Your "speed up" is based on the assumption that all synthesized threads 
are their own parent which is wrong. ie., ppid != tgid of the process.

Before ppid was getting initialized to -1. If you just make that change 
to revert to the -1:

diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c
index d5efa5092ce6..ce4ca061c2e5 100644
--- a/tools/perf/util/event.c
+++ b/tools/perf/util/event.c
@@ -150,8 +150,8 @@ static int perf_event__synthesize_fork(struct 
perf_tool *tool,
  {
     memset(&event->fork, 0, sizeof(event->fork) + machine->id_hdr_size);

-   event->fork.ppid = tgid;
-   event->fork.ptid = tgid;
+   event->fork.ppid = -1;
+   event->fork.ptid = -1;
     event->fork.pid  = tgid;
     event->fork.tid  = pid;
     event->fork.header.type = PERF_RECORD_FORK;

You see the "DON" messages.

David

  parent reply	other threads:[~2015-03-27 20:10 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-03-25 16:51 [PATCH v2] perf tool: Fix ppid for synthesized fork events David Ahern
2015-03-25 19:15 ` Don Zickus
2015-03-25 19:55   ` David Ahern
2015-03-25 20:26     ` Don Zickus
2015-03-26 21:11     ` Don Zickus
2015-03-26 21:37       ` David Ahern
2015-03-27 13:10         ` Don Zickus
2015-03-27 14:03           ` David Ahern
2015-03-27 14:20             ` Arnaldo Carvalho de Melo
2015-03-27 19:49               ` Don Zickus
2015-03-27 20:09                 ` Arnaldo Carvalho de Melo
2015-03-27 20:10                 ` David Ahern [this message]
2015-03-27 20:25                   ` Don Zickus

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=5515B94E.6020706@gmail.com \
    --to=dsahern@gmail.com \
    --cc=acme@kernel.org \
    --cc=dzickus@redhat.com \
    --cc=jmario@redhat.com \
    --cc=jolsa@redhat.com \
    --cc=linux-kernel@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.