From: Johannes Berg <johannes@sipsolutions.net>
To: Paul Mackerras <paulus@samba.org>
Cc: Linux Kernel list <linux-kernel@vger.kernel.org>,
linuxppc-dev list <linuxppc-dev@ozlabs.org>
Subject: Re: time accounting problem (powerpc only?)
Date: Tue, 27 Nov 2007 14:06:20 +0100 [thread overview]
Message-ID: <1196168780.6058.2.camel@johannes.berg> (raw)
In-Reply-To: <18251.59930.30260.145217@cargo.ozlabs.ibm.com>
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On Tue, 2007-11-27 at 20:57 +1100, Paul Mackerras wrote:
> Johannes Berg writes:
>
> > Contrary to what I claimed later in the thread, my 64-bit powerpc box
> > (quad-core G5) doesn't suffer from this problem.
> >
> > Does anybody have any idea? I don't even know how to debug it further.
>
> I see it on my G4 powerbook. However, a compute-bound task runs just
> as fast (i.e. completes in the same elapsed time) as on older kernels,
> so it does look like it is just an accounting problem. If the CPU was
> really spending more than half its time servicing hardware interrupts,
> the task should take more than twice as long to complete.
Exactly. So where do I look for the accounting bug?
johannes
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next prev parent reply other threads:[~2007-11-27 13:09 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-11-23 10:46 Johannes Berg
2007-11-26 16:23 ` Johannes Berg
2007-11-27 5:00 ` Tony Breeds
2007-11-27 13:42 ` Johannes Berg
2007-11-27 9:57 ` Paul Mackerras
2007-11-27 13:06 ` Johannes Berg [this message]
2007-11-26 23:55 ` Johannes Berg
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