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Date: Wed, 11 Aug 2004 09:31:49 +0200
From: Ingo Molnar <mingo@elte.hu>
To: Lee Revell <rlrevell@joe-job.com>
Cc: linux-kernel <linux-kernel@vger.kernel.org>,
       Felipe Alfaro Solana <felipe_alfaro@linuxmail.org>,
       Florian Schmidt <mista.tapas@gmx.net>
Subject: Re: [patch] voluntary-preempt-2.6.8-rc3-O5
Message-ID: <20040811073149.GA4312@elte.hu>
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* Lee Revell <rlrevell@joe-job.com> wrote:

> (jackd/12427): 10882us non-preemptible critical section violated 400
> us preempt threshold starting at kernel_fpu_begin+0x10/0x60 and ending
> at fast_clear_page+0x75/0xa0

to make sure this is a real latency and not some rdtsc weirdness, could
you try the latest version of preempt-timing:

 http://redhat.com/~mingo/voluntary-preempt/preempt-timing-on-2.6.8-rc3-O5-A2

this adds jiffies-based latency values to the printout, e.g.:

  (ksoftirqd/0/2): 3860us [3 jiffy] non-preemptible critical section
  violated 100 us preempt threshold starting at ___do_softirq+0x1b/0x90
  and ending at cond_resched_softirq+0x57/0x70

shows that a 10 jiffy (10 msec) latency happened - which matches the
rdtsc-based 3860 usecs value.

	Ingo