On Tuesday 17 April 2007, Ingo Molnar wrote:
>* Gene Heskett <[email protected]> wrote:
>> This one (v2-rc2) is not a keeper I'm sorry to say, Ingo. v2-rc0 was
>> much better. Watching amanda run with htop, kmails composer is being
>> subjected to 5 to 10 second pauses, and htop says that gzip -best
>> isn't getting more that 15% of the cpu, and the /amandatapes drive is
>> being written to in a regular pattern that seems to be the cause of
>> the pauses according to gkrellm, which also seems to track the size of
>> the writes, and can show anything from 4.3k to 54 megs as being
>> written in one cycle of its screen update.
>
>ok - fortunately the delta between -v2-rc0 and -v2-final is pretty
>small. One difference is the child-runs-first fix. To restore the
>parent-runs-first logic, do this:
>
I'm running 21-rc7-CFS-v2-rc0.1 now.
> echo 0 > /proc/sys/kernel/sched_child_runs_first
This is currently a 1. Reset to 0 by the above.
>does this make any difference?
Hard to tell, not much running except fetchmail/procmail and this composer.
>
>If not then pretty much the only other change was the nice level tweak i
>did. Could you try to grab a few snapshots of scheduling state via
>something like:
>
> while sleep 1; do cat /proc/sched_debug >> to-ingo.txt; done
The crf1.txt is with it=1, the cfr0.txt is with it zeroed.
>(and tell me the PID of the kmail composer, to make sure i'm checking
>the right task's behavior.)
And I let the crf0 version run longer as I was looking for the composer's pid,
but htop (or I) can't see it. Even a ps -e isn't seeing it! But its
running, I'm actively typing in it. So you get 3 files, the third one called
ps-e.txt, in private mail. I thought it was called composer, I really did.
>
>also, as a separate experiment, could you perhaps run this script as
>root:
>
> cd /proc; for N in [1-9]*; do renice -n 0 $N; done
>
>this will move all tasks in the system to nice level 0 and should make
>any nice level handling logic in the scheduler irrelevant. Do you have X
>reniced perhaps?
>
>Lots of system threads have negative or positive nice levels, so once
>you have executed this script, only a reboot will be a practical way to
>restore it to the previous settings.
>
> Ingo
--
Cheers, Gene
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
I have many CHARTS and DIAGRAMS..
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