From: Jack Steiner <steiner@sgi.com>
To: Jesse Barnes <jbarnes@engr.sgi.com>
Cc: wli@holomorphy.org, linux-kernel@vger.kernel.org, edwardsg@sgi.com
Subject: Re: contention on profile_lock
Date: Tue, 2 Nov 2004 14:02:22 -0600 [thread overview]
Message-ID: <20041102200222.GA5135@sgi.com> (raw)
In-Reply-To: <200411021152.16038.jbarnes@engr.sgi.com>
On Tue, Nov 02, 2004 at 11:52:15AM -0800, Jesse Barnes wrote:
> Hmm, the last patch you sent me worked ok, so I'm not sure why we're seeing
> problems with profiling now. There seems to be very heavy contention on
> profile_lock since profile_hook is called unconditionally every timer tick.
> Should it only be called if profiling is enabled? Is there a way we can
> check the notifier list to see if it's empty before calling it or something?
> The only user appears to be oprofile timer based profiling, so in the general
> case we're taking the profile_lock and not doing anything.
>
> Thanks,
> Jesse
Calling profile_hook() only if the notifier list is non-empty seems like a good
step but I don't think that is the complete fix. We need to be able to
enable profiling without killing performance.
--
Thanks
Jack Steiner (steiner@sgi.com) 651-683-5302
Principal Engineer SGI - Silicon Graphics, Inc.
next prev parent reply other threads:[~2004-11-02 20:12 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-11-02 19:52 contention on profile_lock Jesse Barnes
2004-11-02 20:02 ` Jack Steiner [this message]
2004-11-02 21:42 ` Jesse Barnes
2004-11-04 19:56 ` Jesse Barnes
2004-11-04 20:12 ` William Lee Irwin III
2004-11-04 20:49 ` Jesse Barnes
2004-11-04 21:51 ` John Levon
2004-11-04 22:08 ` Jesse Barnes
2004-11-04 21:55 ` Jesse Barnes
2004-11-04 22:16 ` Dipankar Sarma
2004-11-04 22:21 ` John Levon
2004-11-04 22:27 ` Jesse Barnes
2004-11-04 22:52 ` John Levon
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