Re: [PATCH] x86 idle: repair large-server 50-watt idle-powerregression

From: Ingo Molnar
Date: Thu Dec 19 2013 - 16:17:14 EST



* H. Peter Anvin <hpa@xxxxxxxxx> wrote:

> CLFLUSH is only (guaranteed to be) ordered with respect to MFENCE
> according to the SDM.

Yes, I quoted the relevant text a couple of hours ago, CLFLUSH is
pretty special, so it's not ordered against atomics or serializing
instructions for example - only ordered against explict MFENCE calls,
which on x86 is mb()/smp_mb().

Thanks,

Ingo
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