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Re: time stamp counter in "make check"

From: Carlos O'Donell <carlos_odonell at mentor dot com>
To: Dmitrieva Liubov <liubov dot dmitrieva at gmail dot com>
Cc: <libc-alpha at sourceware dot org>
Date: Thu, 12 Jul 2012 11:18:21 -0400
Subject: Re: time stamp counter in "make check"
References: <CAHjhQ93k9cAv9=hh8W0BbBsR6Gf6fFC4498j21ksfrjcFCME4w@mail.gmail.com>

On 7/12/2012 10:58 AM, Dmitrieva Liubov wrote:
> So, my proposal is to change from "rdtsc" instruction to "rdtscp"
> instruction (which is a serializing variant of the RDTSC)  if rdtscp
> is available for target architecture.
> This definitely solves the issue with negatives values.

I see no problem in replacing rdtsc with rdtscp if the target machine
has support for rdtscp.

Note:
I never liked that ./sysdeps/i386/i686/hp-timing.h didn't use CPUID
as a barrier, since IMO it would seem to violate some of the constraints
of the interfaces that are built upon hp-timing.h. I would be happy
to see this changed to use rdtscp or cpuid. Though this is a distinct
patch from what your suggesting.

Cheers,
Carlos.
-- 
Carlos O'Donell
Mentor Graphics / CodeSourcery
carlos_odonell@mentor.com
carlos@codesourcery.com
+1 (613) 963 1026

Follow-Ups:
- Re: time stamp counter in "make check"
  - From: Dmitrieva Liubov

References:
- time stamp counter in "make check"
  - From: Dmitrieva Liubov

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