linux-kernel - Re: [PATCH] x86/smpboot: check if CLFLUSH is actually necessary

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Message-ID: <54DBCFD6.8000509@zytor.com>
Date:	Wed, 11 Feb 2015 13:55:34 -0800
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Scotty Bauer <sbauer@....utah.edu>, tglx@...utronix.de,
	mingo@...heat.com
CC:	linux-kernel@...r.kernel.org, x86@...nel.org
Subject: Re: [PATCH] x86/smpboot: check if CLFLUSH is actually necessary

On 01/30/2015 01:26 PM, Scotty Bauer wrote:
> mwait_play_dead previously issued a CLFLUSH to work around a bug on
> some xeon processors. We can now determine if the CPU is a buggy CPU.
> This patch checks if if we're on a buggy CPU which allows non-buggy
> cpu's to eliminate the CLFLUSH.

Here is my first question: does this matter at all?  Otherwise I don't
see a point.

	-hpa


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