From: Chris Friesen <cfriesen@nortelnetworks.com>
To: root@chaos.analogic.com
Cc: George Anzinger <george@mvista.com>,
Peter Chubb <peter@chubb.wattle.id.au>,
Stephen Hemminger <shemminger@osdl.org>,
Gabriel Paubert <paubert@iram.es>,
john stultz <johnstul@us.ibm.com>, Joe Korty <joe.korty@ccur.com>,
Linus Torvalds <torvalds@osdl.org>,
lkml <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@osdl.org>
Subject: Re: gettimeofday resolution seriously degraded in test9
Date: Thu, 30 Oct 2003 17:50:37 -0500 [thread overview]
Message-ID: <3FA195BD.2040701@nortelnetworks.com> (raw)
In-Reply-To: Pine.LNX.4.53.0310301645170.16005@chaos
Richard B. Johnson wrote:
> There isn't any magic that can solve this problem. It turns out
> that with later Intel CPUs, one can get CPU-clock resolution
> from rdtsc. However, this is hardware-specific. If somebody
> modifies the gettimeofday() and the POSIX clock routines to
> use rdtsc when available, a lot of problems will go away.
Its not just x86. PowerPC has a similar call, so does MIPS, and I'm
sure most other modern cpus do too.
The only problem with this stuff is that they usually slow down when the
cpu does, so laptops and other power-managed chips cause complexities.
Chris
--
Chris Friesen | MailStop: 043/33/F10
Nortel Networks | work: (613) 765-0557
3500 Carling Avenue | fax: (613) 765-2986
Nepean, ON K2H 8E9 Canada | email: cfriesen@nortelnetworks.com
next prev parent reply other threads:[~2003-10-30 23:00 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-10-27 23:44 gettimeofday resolution seriously degraded in test9 Joe Korty
2003-10-28 0:15 ` Stephen Hemminger
2003-10-28 0:29 ` john stultz
2003-10-28 1:17 ` Stephen Hemminger
2003-10-28 11:55 ` Gabriel Paubert
2003-10-28 18:21 ` Stephen Hemminger
2003-10-29 10:07 ` Gabriel Paubert
2003-10-29 19:38 ` Stephen Hemminger
2003-10-29 22:50 ` Peter Chubb
2003-10-30 21:33 ` George Anzinger
2003-10-30 21:52 ` Richard B. Johnson
2003-10-30 22:50 ` Chris Friesen [this message]
2003-10-30 23:15 ` Peter Chubb
2003-10-30 23:47 ` George Anzinger
2003-11-25 16:42 ` [RFC] possible erronous use of tick_usec in do_gettimeofday Joe Korty
2003-11-25 17:13 ` Stephen Hemminger
2003-11-25 19:57 ` George Anzinger
2003-11-25 21:12 ` Joe Korty
2003-11-25 23:26 ` George Anzinger
2003-10-30 23:27 ` gettimeofday resolution seriously degraded in test9 George Anzinger
2003-10-30 10:39 ` Gabriel Paubert
[not found] <LphK.2Dl.15@gated-at.bofh.it>
[not found] ` <Lq47.3Go.11@gated-at.bofh.it>
[not found] ` <LqGL.4zF.11@gated-at.bofh.it>
[not found] ` <LAPN.1dU.11@gated-at.bofh.it>
[not found] ` <LGLz.1h2.5@gated-at.bofh.it>
2003-10-28 19:19 ` David Mosberger-Tang
2003-10-28 19:59 ` Stephen Hemminger
2003-10-29 0:19 ` David Mosberger
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