From: Terje Eggestad <terje.eggestad@scali.com>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Davide Libenzi <davidel@xmailserver.org>,
Ben Greear <greearb@candelatech.com>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: a faster way to gettimeofday? rdtsc strangeness
Date: 07 Mar 2002 16:43:35 +0100 [thread overview]
Message-ID: <1015515815.4373.61.camel@pc-16.office.scali.no> (raw)
In-Reply-To: <E16iz57-0002SW-00@the-village.bc.nu>
In-Reply-To: <E16iz57-0002SW-00@the-village.bc.nu>
On Thu, 2002-03-07 at 15:41, Alan Cox wrote:
> > If you have a CPU that begin throttling it usually cut the CPU clock in
> > half and the rdtsc counter count half a fast.
>
> They normally adjust the STPCLK which is just fine. I've only seen a few
> laptops that do it other ways. More fun are people running mixed 300/450
> BP6 boards where the tsc varies by cpu
Can /proc/cpuinfo really be trusted in figuring out how long a cycle is?
--
_________________________________________________________________________
Terje Eggestad mailto:terje.eggestad@scali.no
Scali Scalable Linux Systems http://www.scali.com
Olaf Helsets Vei 6 tel: +47 22 62 89 61 (OFFICE)
P.O.Box 150, Oppsal +47 975 31 574 (MOBILE)
N-0619 Oslo fax: +47 22 62 89 51
NORWAY
_________________________________________________________________________
next prev parent reply other threads:[~2002-03-07 15:44 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-03-06 3:41 a faster way to gettimeofday? Ben Greear
2002-03-06 3:58 ` Davide Libenzi
2002-03-06 4:20 ` Ben Greear
2002-03-06 4:31 ` Davide Libenzi
2002-03-06 4:34 ` Davide Libenzi
2002-03-07 14:14 ` a faster way to gettimeofday? rdtsc strangeness Terje Eggestad
2002-03-07 14:41 ` Alan Cox
2002-03-07 15:43 ` Terje Eggestad [this message]
2002-03-07 16:17 ` Alan Cox
2002-03-07 18:32 ` H. Peter Anvin
2002-03-08 1:32 ` Jamie Lokier
2002-03-08 1:35 ` H. Peter Anvin
2002-03-08 1:57 ` Jamie Lokier
2002-03-08 18:30 ` gettimeofday() system call timing curiosity Jamie Lokier
2002-03-08 18:50 ` H. Peter Anvin
2002-03-08 20:16 ` Jamie Lokier
2002-03-08 20:30 ` Davide Libenzi
2002-03-08 18:54 ` Richard B. Johnson
2002-03-08 19:06 ` johan.adolfsson
2002-03-08 19:16 ` H. Peter Anvin
2002-03-08 19:45 ` Richard B. Johnson
2002-03-08 20:29 ` johan.adolfsson
2002-03-08 20:43 ` Alan Cox
2002-03-09 3:03 ` pjd
2002-03-09 18:51 ` Alan Cox
2002-03-09 3:15 ` Kelsey Hudson
2002-03-08 19:19 ` Alan Cox
2002-03-08 20:40 ` george anzinger
2002-03-06 20:45 ` a faster way to gettimeofday? dean gaudet
2002-03-06 21:31 ` Chris Ball
2002-03-06 22:25 ` george anzinger
2002-03-07 0:04 ` vsyscalls Mark Mielke
2002-03-06 16:16 ` a faster way to gettimeofday? Chris Friesen
2002-03-06 16:54 ` Richard B. Johnson
2002-03-11 22:47 ` OBATA Noboru
2002-03-12 13:06 ` Jamie Lokier
2002-03-12 15:12 ` OBATA Noboru
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