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Date:      Mon, 12 Oct 2009 01:20:48 +0200
From:      Attilio Rao <attilio@freebsd.org>
To:        Larry Rosenman <ler@lerctr.org>
Cc:        freebsd-current@freebsd.org
Subject:   Re: Scheduler weirdness
Message-ID:  <3bbf2fe10910111620p3aa5d4cbgb5db2659d8477142@mail.gmail.com>
In-Reply-To: <100658409950385d656fb5d8030af744.squirrel@webmail.lerctr.org>
References:  <6729ad0409e449f8dbda69ecd8feb618.squirrel@webmail.lerctr.org> <3bbf2fe10910111611p2f48d89cpa80350980f4f03e4@mail.gmail.com> <100658409950385d656fb5d8030af744.squirrel@webmail.lerctr.org>

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2009/10/12 Larry Rosenman <ler@lerctr.org>:
>
> On Sun, October 11, 2009 6:11 pm, Attilio Rao wrote:
>> 2009/10/12 Larry Rosenman <ler@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


-- 
Peace can only be achieved by understanding - A. Einstein



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