linux-kernel - Re: [PATCH v2] cpuidle: Fix the menu governor to boost IO performance

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Message-ID: <20091108143908.78dd97a1@infradead.org>
Date:	Sun, 8 Nov 2009 14:39:08 -0800
From:	Arjan van de Ven <arjan@...radead.org>
To:	Corrado Zoccolo <czoccolo@...il.com>
Cc:	linux-kernel@...r.kernel.org,
	Andrew Morton <akpm@...ux-foundation.org>, lenb@...nel.org,
	mingo@...e.hu, yanmin_zhang@...ux.intel.com, jens.axboe@...cle.com,
	Ivan Kokshaysky <ink@...assic.park.msu.ru>
Subject: Re: [PATCH v2] cpuidle: Fix the menu governor to boost IO
 performance

On Sun, 8 Nov 2009 22:59:43 +0100
Corrado Zoccolo <czoccolo@...il.com> wrote:

> Unfortunately, I have seen polling residency times > 1ms, so it must
> not be so accurate.


hmm I wonder if the timer hardware in use has a much larger
granularity than usecs... 
because that rounding up could cost us dearly.

wonder if we should do some form of "check for timer expiry" as part of
the polling loop.. that'd cut latency way down as well ;)

-- 
Arjan van de Ven 	Intel Open Source Technology Centre
For development, discussion and tips for power savings, 
visit http://www.lesswatts.org
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