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From: Lee Revell <rlrevell@joe-job.com>
To: thockin@hockin.org
Cc: Steven Rostedt <rostedt@goodmis.org>, Ingo Molnar <mingo@elte.hu>,
	john stultz <johnstul@us.ibm.com>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [RT] read_tsc: ACK! TSC went backward! Unsynced TSCs?
Date: Mon, 28 Nov 2005 12:39:28 -0500	[thread overview]
Message-ID: <1133199568.7416.31.camel@mindpipe> (raw)
In-Reply-To: <20051128173040.GA32547@hockin.org>

On Mon, 2005-11-28 at 09:30 -0800, thockin@hockin.org wrote:
> The kernel's use of TSC is wholly incorrect.  TSCs can ramp up and
> down and *do* vary between nodes as well as between cores within a
> node.  You really can not compare TSCs between cpu cores at all, as is
> (and the kernel assumes 1 global TSC in at least a few places). 

That's one way to look at it; another is that the AMD dual cores have a
broken TSC implementation.  The kernel's use of the TSC was never a
problem in the past...

Lee


  reply	other threads:[~2005-11-28 17:52 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-11-28 12:05 [RT] read_tsc: ACK! TSC went backward! Unsynced TSCs? Steven Rostedt
2005-11-28 12:30 ` Jonas Oreland
2005-11-28 12:59   ` Steven Rostedt
2005-11-28 14:21     ` Ingo Molnar
2005-11-28 15:38   ` Lee Revell
2005-11-28 17:30 ` thockin
2005-11-28 17:39   ` Lee Revell [this message]
2005-11-28 18:30     ` Dave Jones
2005-11-28 18:35     ` thockin
2005-11-29 14:06       ` Andi Kleen
2005-11-29 16:52         ` thockin
2005-11-29 16:48           ` Andi Kleen

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