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Date: Thu, 9 Dec 2004 22:56:38 +0100
From: Ingo Molnar <mingo@elte.hu>
To: Mark_H_Johnson@raytheon.com
Cc: Amit Shah <amit.shah@codito.com>,
       Karsten Wiese <annabellesgarden@yahoo.de>, Bill Huey <bhuey@lnxw.com>,
       Adam Heath <doogie@debian.org>, emann@mrv.com,
       Gunther Persoons <gunther_persoons@spymac.com>,
       "K.R. Foley" <kr@cybsft.com>, linux-kernel@vger.kernel.org,
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       Thomas Gleixner <tglx@linutronix.de>,
       Michal Schmidt <xschmi00@stud.feec.vutbr.cz>
Subject: Re: [patch] Real-Time Preemption, -RT-2.6.10-rc2-mm3-V0.7.32-6
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* Mark_H_Johnson@raytheon.com <Mark_H_Johnson@raytheon.com> wrote:

> >well, i think this measurement issue needs resolving before jumping to
> >any generic conclusions. Not a single trace is extremely suspect. The
> >userspace timestamps are rdtsc based, or gettimeofday() based?

> rdtsc. Its actually code you sent me a while ago :-) when you
> suspected a measurement problem before.

could you try to put a few deliberate delays into the code - does the
kernel based tracing method pick the latency up correctly? (attaching to
the thread via gdb and then 'cont'-ing it ought to be enough i think.)
It's very weird.

	Ingo