From: David Ahern <dsahern@gmail.com>
To: Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>,
Joe Mario <jmario@redhat.com>
Cc: Don Zickus <dzickus@redhat.com>,
linux-kernel@vger.kernel.org, Jiri Olsa <jolsa@redhat.com>
Subject: Re: [PATCH] perf tool: Fix ppid for synthesized fork events
Date: Wed, 25 Mar 2015 09:03:38 -0600 [thread overview]
Message-ID: <5512CE4A.2060800@gmail.com> (raw)
In-Reply-To: <20150325132405.GB13759@kernel.org>
On 3/25/15 7:24 AM, Arnaldo Carvalho de Melo wrote:
> So it starts when there are tons of threads in the system, for which
> synthezing from /proc will have to take place, without looking again at
> that patch, I can't think about what would be a problem :-\
3 extra lines are read from /proc/pid/status:
Name: bash
State: S (sleeping)
Tgid: 6046
< current patch breaks here>
Ngid: 0
Pid: 6046
PPid: 6045
< my patch reads these 3 lines, repeats the memcmp and does an atoi on
the PPid: value >
Let me remove that loop by reading in 4k at a time and making a single
pass. That should bring down the overhead, but filling in the ppid will
add some.
David
next prev parent reply other threads:[~2015-03-25 15:03 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-19 17:41 [PATCH] perf tool: Fix ppid for synthesized fork events David Ahern
2015-03-19 20:56 ` Don Zickus
2015-03-19 21:06 ` David Ahern
2015-03-20 14:01 ` Arnaldo Carvalho de Melo
2015-03-24 20:10 ` Don Zickus
2015-03-24 21:12 ` David Ahern
2015-03-25 12:22 ` Joe Mario
2015-03-25 13:24 ` Arnaldo Carvalho de Melo
2015-03-25 15:03 ` David Ahern [this message]
2015-03-25 19:20 ` Don Zickus
2015-03-25 16:57 ` David Ahern
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