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Subject: Re: [PATCH] x86/TSC: Use RDTSCP
To:     Andy Lutomirski <luto@kernel.org>, Borislav Petkov <bp@alien8.de>
Cc:     X86 ML <x86@kernel.org>, LKML <linux-kernel@vger.kernel.org>,
        John Stultz <john.stultz@linaro.org>,
        Tom Lendacky <Thomas.Lendacky@amd.com>
References: <20181119184556.11479-1-bp@alien8.de>
 <CALCETrV34q-BP2w8A1s82-a8Hg062=RYzk+SCOa31W7ftsznPA@mail.gmail.com>
From:   "H. Peter Anvin" <hpa@zytor.com>
Message-ID: <a1b79c06-ab34-e774-df6b-c98323b13bae@zytor.com>
Date:   Mon, 19 Nov 2018 12:17:35 -0800
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On 11/19/18 11:52 AM, Andy Lutomirski wrote:
> 
> I thought I benchmarked this on Intel at some point and found the
> LFENCE;RDTSC variant to be slightly faster.  But I believe you, so:
> 
> Acked-by: Andy Lutomirski <luto@kernel.org>
> 

As long as the difference isn't significant, the simplicity would seem to be a
win.

	-hpa