From: Matt Mackall <mpm@selenic.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: "S.Çağlar Onur" <caglar@pardus.org.tr>,
LKML <linux-kernel@vger.kernel.org>,
"Arjan van de Ven" <arjan@linux.intel.com>
Subject: Re: Rescheduling interrupts
Date: Tue, 22 Jan 2008 11:03:49 -0600 [thread overview]
Message-ID: <1201021429.14436.45.camel@cinder.waste.org> (raw)
In-Reply-To: <20080122160557.GA31831@elte.hu>
On Tue, 2008-01-22 at 17:05 +0100, Ingo Molnar wrote:
> * S.Çağlar Onur <caglar@pardus.org.tr> wrote:
>
> > > My theory is that for whatever reason we get "repeat" IPIs: multiple
> > > reschedule IPIs although the other CPU only initiated one.
> >
> > Ok, please see http://cekirdek.pardus.org.tr/~caglar/dmesg.3rd :)
>
> hm, the IPI sending and receiving is nicely paired up:
>
> [ 625.795008] IPI (@smp_reschedule_interrupt) from task swapper:0 on CPU#1:
> [ 625.795223] IPI (@native_smp_send_reschedule) from task amarokapp:2882 on CPU#1:
>
> amarokapp does wake up threads every 20 microseconds - that could
> explain it. It's probably Xorg running on one core, amarokapp on the
> other core. That's already 100 reschedules/sec.
That suggests we want an "anti-load-balancing" heuristic when CPU usage
is very low. Migrating everything onto one core when we're close to idle
will save power and probably reduce latencies.
--
Mathematics is the supreme nostalgia of our time.
next prev parent reply other threads:[~2008-01-22 17:05 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-01-21 23:19 Rescheduling interrupts S.Çağlar Onur
2008-01-22 10:57 ` Ingo Molnar
2008-01-22 12:55 ` S.Çağlar Onur
2008-01-22 15:23 ` Ingo Molnar
2008-01-22 15:37 ` Ingo Molnar
2008-01-22 16:00 ` S.Çağlar Onur
2008-01-22 15:55 ` S.Çağlar Onur
2008-01-22 16:05 ` Ingo Molnar
2008-01-22 16:11 ` S.Çağlar Onur
2008-01-22 16:22 ` S.Çağlar Onur
2008-01-22 17:03 ` Matt Mackall [this message]
2008-01-22 19:27 ` Ingo Molnar
[not found] ` <p73fxwoncs4.fsf@crumb.suse.de>
2008-01-23 15:52 ` Matt Mackall
2008-05-13 18:03 ` Vegard Nossum
2008-05-13 19:04 ` Vegard Nossum
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=1201021429.14436.45.camel@cinder.waste.org \
--to=mpm@selenic.com \
--cc=arjan@linux.intel.com \
--cc=caglar@pardus.org.tr \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@elte.hu \
/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.