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Date: Fri, 10 Dec 2004 22:12:35 +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,
       Florian Schmidt <mista.tapas@gmx.net>,
       Fernando Pablo Lopez-Lezcano <nando@ccrma.Stanford.EDU>,
       Lee Revell <rlrevell@joe-job.com>, Rui Nuno Capela <rncbc@rncbc.org>,
       Shane Shrybman <shrybman@aei.ca>, Esben Nielsen <simlo@phys.au.dk>,
       Thomas Gleixner <tglx@linutronix.de>,
       Michal Schmidt <xschmi00@stud.feec.vutbr.cz>
Subject: Re: [patch] Real-Time Preemption, -RT-2.6.10-rc2-mm3-V0.7.32-15
Message-ID: <20041210211235.GB5864@elte.hu>
References: <OF8AB2B6D9.572374AA-ON86256F66.0061EFA8-86256F66.0061F00A@raytheon.com>
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* Mark_H_Johnson@raytheon.com <Mark_H_Johnson@raytheon.com> wrote:

> [3] Some traces show information on both CPU's and then a long period
> with no traces from the other. Here is an example...

> <unknown-2847  1d.h.    4µs : rebalance_tick (scheduler_tick)
> <unknown-2847  1d.h.    5µs : irq_exit (apic_timer_interrupt)
> <unknown-2847  1d...    5µs < (0)

> ... no more traces from CPU 1 ...

PID 2847 returned to userspace at timestamp 5µs. Userspace then can take
an arbitrary amount of time until it calls the kernel again.

	Ingo