From: Lee Revell <rlrevell@joe-job.com>
To: Chris Friesen <cfriesen@nortelnetworks.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Robert Love <rml@novell.com>, "Jack O'Quin" <joq@io.com>
Subject: Re: How is user space notified of CPU speed changes?
Date: Fri, 22 Oct 2004 19:25:58 -0400 [thread overview]
Message-ID: <1098487558.1440.20.camel@krustophenia.net> (raw)
In-Reply-To: <4179623C.9050807@nortelnetworks.com>
On Fri, 2004-10-22 at 13:40 -0600, Chris Friesen wrote:
> Lee Revell wrote:
>
> > Seems like you are implying that any userspace app that needs to know
> > the CPU speed is broken. Is this correct?
>
> No, we're saying that Intel's tsc implementation is broken. <grin>
>
> x86 really could use an on-die register that increments at 1GHz independent of
> clock speed and is synchronized across all CPUs in an SMP box.
Like this? (posted to jackit-devel):
On Fri, 2004-10-22 at 18:20 -0500, Jack O'Quin wrote:
> On PowerPC, JACK uses the lower half of the 64-bit Timebase register,
> which is accessible from user mode. This is better then the i386
> cycle counter, I believe. See: `config/cpu/powerpc/cycles.h', the
> comment about only using it for SMP is bogus. We use this for both
> MacOS X and Linux.
--
Lee Revell <rlrevell@joe-job.com>
next prev parent reply other threads:[~2004-10-22 23:35 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-10-21 23:01 How is user space notified of CPU speed changes? Lee Revell
2004-10-22 11:23 ` Alan Cox
2004-10-22 14:12 ` Con Kolivas
2004-10-22 18:05 ` Lee Revell
2004-10-22 18:57 ` Andreas Dilger
2004-10-22 19:40 ` Chris Friesen
2004-10-22 19:46 ` Lee Revell
2004-10-22 20:28 ` Alan Cox
2004-10-22 21:46 ` Chris Friesen
2004-10-22 23:25 ` Lee Revell [this message]
2004-10-25 15:28 ` Chris Friesen
2004-10-23 5:10 ` Lee Revell
2004-10-23 10:53 ` Matthew Garrett
2004-10-23 21:19 ` Alan Cox
2004-10-23 22:42 ` Lee Revell
2004-10-23 23:17 ` Jon Masters
2004-10-24 1:40 ` Lee Revell
2004-10-24 14:02 ` Alan Cox
2004-10-26 2:38 ` Lee Revell
2004-10-26 4:05 ` Lee Revell
2004-10-23 23:35 ` Jon Masters
2004-10-23 23:36 ` Jon Masters
2004-10-24 14:04 ` Alan Cox
2004-10-25 5:53 ` Joel Becker
2004-10-24 20:02 ` Robert Love
[not found] <1098399709.4131.23.camel@krustophenia.net.suse.lists.linux.kernel>
[not found] ` <1098444170.19459.7.camel@localhost.localdomain.suse.lists.linux.kernel>
[not found] ` <1098508238.13176.17.camel@krustophenia.net.suse.lists.linux.kernel>
[not found] ` <1098566366.24804.8.camel@localhost.localdomain.suse.lists.linux.kernel>
2004-10-23 23:54 ` Andi Kleen
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