Re: [patch] voluntary-preempt-2.6.9-rc1-bk4-Q5

From: Ingo Molnar (mingo_at_elte.hu)
Date: 08/31/04

  • Next message: Maciej Górnicki: "[2.6.9-rc1-bk7] LIBATA - "irq 11: nobody cared" on sil 3112a" 
    Date:	Tue, 31 Aug 2004 22:37:39 +0200
To: Mark_H_Johnson@raytheon.com

    * Mark_H_Johnson@raytheon.com <Mark_H_Johnson@raytheon.com> wrote:

    > >since the latency tracer does not trigger, we need a modified tracer to
    > >find out what's happening during such long delays. I've attached the
    > >'user-latency-tracer' patch ontop of -Q5, which is a modification of the
    > >latency tracer.
    > Grr. I should have checked before I built with this patch. With this in
    > I now get the
    > kernel: Could not allocate 4 bytes percpu data
    > messages again. Need to increase that data area so
    > #define PERCPU_ENOUGH_ROOM 196608
    > or something similar (should leave about 50K free for modules).

    ok, i've upped that value in my tree too.

    > I will rebuild with this change plus the latest of the others.

    since your traces do show those 'mystic' latency incidents causing
    200-500 usec overhead in few-instructions code paths, perhaps the 1 msec
    jitter you are seeing could a consequence of this too. So perhaps it
    would make sense to first try disabling IDE DMA, to see whether this has
    any effect on the magic latencies.

            Ingo
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  • Next message: Maciej Górnicki: "[2.6.9-rc1-bk7] LIBATA - "irq 11: nobody cared" on sil 3112a"

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