Messages in this thread | | | Subject | Re: [PATCH] x86: Add clflush before monitor for Intel 7400 series | From | Andi Kleen <> | Date | Sat, 18 Oct 2008 09:15:39 +0200 |
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"H. Peter Anvin" <hpa@zytor.com> writes:
> Pallipadi, Venkatesh wrote: >>>> >>> I guess I'm a bit confused about the tradeoff of CLFLUSH versus simply >>> disabling MWAIT. This is a relatively recent processor and so >>> optimizing matters (if this was a P4 I would be more worried about what >>> has least impact on the kernel as a whole.) >> As of now this is only for a limited models of CPUs (MP CPUs) >> and not a norm. It is a errata on this CPU and not >> something that is going to become architectural. >> > > Yes, I understand. However, there is still the option to disable > MWAIT, and the question is still open if it makes sense.
This would mean falling back to the IO port interface for deeper C states. Even with the CLFLUSH MWAIT is a much better (and I believe faster) interface.
-Andi -- ak@linux.intel.com
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