From: Christian Vogel <vogel@skunk.physik.uni-erlangen.de>
Date: Thu, 31 Jul 2003 16:44:57 +0200
To: Charles Lepple <clepple@ghz.cc>
Cc: linux-kernel@vger.kernel.org
Subject: Re: linux-2.6.0-test2: Never using pm_idle (CPU wasting power)
Message-ID: <20030731164457.A6993@skunk.physik.uni-erlangen.de>
References: <20030731150722.A5938@skunk.physik.uni-erlangen.de> <17207.216.12.38.216.1059660771.squirrel@www.ghz.cc>
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In-Reply-To: <17207.216.12.38.216.1059660771.squirrel@www.ghz.cc>; from clepple@ghz.cc on Thu, Jul 31, 2003 at 10:12:51AM -0400
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Hi,

On Thu, Jul 31, 2003 at 10:12:51AM -0400, Charles Lepple wrote:
> about this (haven't instrumented it all the way), it also appears that
> pm_idle is not being called (for up to an hour, in some cases). Sometimes
> it takes only a few minutes, and other times, it appears to kick in after
> heavy CPU usage (kernel compiles, cpuburn, etc.).

Yes, exactly. Up to the first time need_resched() returns true and
the outer while(1){ } loop loops to update the idle-variable. Unfortunately
this never was the case on my system for a long time...

Probably the idle loop uses this local variable to be more cache-friendly,
but then any module updating pm_idle should probably set need_resched
to force an update of the idle function pointer?

	Chris

-- 
Read the OSI protocol specifications? I can't even *lift* them!
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