linux-kernel - Re: Rescheduling interrupts

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Message-ID: <20080122160557.GA31831@elte.hu>
Date:	Tue, 22 Jan 2008 17:05:57 +0100
From:	Ingo Molnar <mingo@...e.hu>
To:	S.Çağlar Onur <caglar@...dus.org.tr>
Cc:	LKML <linux-kernel@...r.kernel.org>,
	Arjan van de Ven <arjan@...ux.intel.com>
Subject: Re: Rescheduling interrupts


* S.Çağlar Onur <caglar@...dus.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.

	Ingo
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