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From: Chris Friesen <cfriesen@nortelnetworks.com>
To: Lee Revell <rlrevell@joe-job.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: Mon, 25 Oct 2004 09:28:13 -0600	[thread overview]
Message-ID: <417D1B8D.3000709@nortelnetworks.com> (raw)
In-Reply-To: <1098487558.1440.20.camel@krustophenia.net>

Lee Revell wrote:
> On Fri, 2004-10-22 at 13:40 -0600, Chris Friesen wrote:
>>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.

Yes, ppc tbr is nice.  It's actually lower resolution than the x86 one, but it 
might be better for smp and freq changes--not sure.

Chris

  reply	other threads:[~2004-10-25 15:32 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
2004-10-25 15:28         ` Chris Friesen [this message]
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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