Re: Scheduler weirdness

From: Larry Rosenman <ler_at_lerctr.org>
Date: Sun, 11 Oct 2009 20:43:28 -0500
On Sun, October 11, 2009 6:20 pm, Attilio Rao wrote:
> 2009/10/12 Larry Rosenman <ler_at_lerctr.org>:
>>
>> On Sun, October 11, 2009 6:11 pm, Attilio Rao wrote:
>>> 2009/10/12 Larry Rosenman <ler_at_lerctr.org>:
>>>>
>>>> Ok, running RELENG_8 from Friday (10/9/2009).
>>>>
>>>> If I have 4 Folding-at-home processes running (they nice themselves)
>>>> the
>>>> system is slow as a dog.
>>>>
>>>> If I stop them, it's speedy.
>>>>
>>>> This is running SCHED_ULE
>>>>
>>>> is this expected?
>>>>
>>>> What can I do to help?
>>>
>>> Can you please produce the schedgraph output for this workload?
>>> Do you know how to setup it?
>>
>> I'm not familiar with this.  What do I need to do?
>
> - Recompile your kernel with the following options:
>   KTR
>   KTR_COMPILE=(KTR_SCHED)
>   KTR_MASK=(KTR_SCHED)
>   KTR_ENTRIES=262144
>
> - Run the buggy workload
> - When the slowness has been experienced a bit (a reasonable timeframe
> is within 10/20 secs) do: sysctl debug.ktr.mask=0
> - do: ktrdump -ct > ktr.out
> - send here this file along with the number and frequency of your CPUs

Sent under separate cover direct to Attilio.

Thanks, Attilio!
>
> Thanks,
> Attilio
>
>
> --
> Peace can only be achieved by understanding - A. Einstein
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-- 
Larry Rosenman                     http://www.lerctr.org/~ler
Phone: +1 512-248-2683                 E-Mail: ler_at_lerctr.org
US Mail: 430 Valona Loop, Round Rock, TX 78681-3893
Received on Sun Oct 11 2009 - 23:43:30 UTC

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