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Date: Sun, 2 Sep 2007 09:46:22 +0200
From: Andi Kleen <andi@firstfloor.org>
To: Ingo Molnar <mingo@elte.hu>
Cc: Andi Kleen <andi@firstfloor.org>,
       Venki Pallipadi <venkatesh.pallipadi@intel.com>,
       Thomas Gleixner <tglx@linutronix.de>,
       Andrew Morton <akpm@linux-foundation.org>,
       linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] Track accurate idle time with tick_sched.idle_sleeptime
Message-ID: <20070902074622.GA16045@one.firstfloor.org>
References: <20070827215611.GA30396@linux-os.sc.intel.com> <p73bqcmvxc6.fsf@bingen.suse.de> <20070902072806.GC5075@elte.hu>
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> at least the current out-of-idle code already does what amounts to a 
> PM-timer read when exiting from C2 or C3 mode. The 

C2/C3 are already slow. I more worry about C1.

Also doing two instead of one can have an impact even on C2+, especially
when the operation can be thousands of cycles.

-Andi