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Date: Fri, 6 Aug 2010 16:51:12 +1000
From: Anton Blanchard <anton@samba.org>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Subject: Re: [PATCH] powerpc: inline ppc64_runlatch_off
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Hi,

> remind me why we need to do that runlatch thing on these CPUs at all ?

The PMU uses it so events can be constructed that count only non idle cycles.
I think the power management hardware on POWER6 and POWER7 also use the
runlatch state to determine how busy a CPU is.

Anton