Scheduler weirdness

[Attilio Rao]

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

Thanks,
Attilio


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