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From: Andrew Morton <akpm@linux-foundation.org>
To: Arjan van de Ven <arjan@infradead.org>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] cpuidle: Add a repeating pattern detector to the menu governor
Date: Mon, 10 May 2010 19:43:29 -0400	[thread overview]
Message-ID: <20100510194329.f49eeb96.akpm@linux-foundation.org> (raw)
In-Reply-To: <20100510182746.7e923812@infradead.org>

On Mon, 10 May 2010 18:27:46 -0700 Arjan van de Ven <arjan@infradead.org> wrote:

> On Mon, 10 May 2010 14:38:50 -0700
> Andrew Morton <akpm@linux-foundation.org> wrote:
> 
> > > +	if (avg && stddev < STDDEV_THRESH)
> > > +		data->predicted_us = avg;
> > > +}
> > 
> > You got lucky there, because INTERVALS is a power of two.  If someone
> > changes INTERVALS to 7, this code will ask for __udivdi3 and won't
> > link on i364.
> 
> yeah you'd think it almost isn't an accident ;-)

If it was deliberate the code would read

	avg >>= INTERVALS_SHIFT;

:-p

  reply	other threads:[~2010-05-11  2:45 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-05-09 23:02 [PATCH 0/2] Some improvements to the cpuidle menu governor Arjan van de Ven
2010-05-09 23:03 ` [PATCH 1/2] cpuidle: Fix incorrect optimziation Arjan van de Ven
2010-05-09 23:04 ` [PATCH 2/2] cpuidle: Add a repeating pattern detector to the menu governor Arjan van de Ven
2010-05-10 21:38   ` Andrew Morton
2010-05-11  1:27     ` Arjan van de Ven
2010-05-10 23:43       ` Andrew Morton [this message]
2010-05-19 19:51   ` Frank Rowand
2010-05-21 19:43     ` Andrew Morton
2010-05-22  5:23       ` Arjan van de Ven
2010-05-22 16:31       ` Arjan van de Ven

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