Re: Trying out SCHED_BATCH

From: Con Kolivas
Date: Wed Dec 29 2004 - 17:59:31 EST


Paolo Ciarrocchi wrote:
On Thu, 30 Dec 2004 07:28:35 +1100, Con Kolivas <kernel@xxxxxxxxxxx> wrote:

Maciej Soltysiak wrote:

Hi

Con wrote:


Only the staircase scheduler currently has an implementation of
sched_batch and you need 2 more patches on top of the staircase patch
for it to work.

Hmm, Is it feasable to write a sched_batch policy for the current linux
schedulers?

Yes.

The proper way to make a sched_batch implementation is more
comprehensive than what is made for staircase to prevent a deadlock
based on a batch task getting an important lock in the kernel and not
being able to release it due to a sched_normal task being higher
priority than it that is actually trying to get the lock. There is code
in the staircase version to prevent this from happening but probably not
complete enough in design to prevent everything. However it works and I
haven't had any reports of lockups since I implemented the extra checking.

Would you like me to create a version like that? I don't have the time
to try and make a more comprehensive solution and follow the debugging
of such a beast.


I mean, if there are people that want it bad, maybe it would be nice to
be able
to use a version of sched_batch that would work without the staircase
scheduler.
It is still experimental, right?

No it's not experimental. It is very stable and used in production systems.


Are you gointo to push to Linus/Andrew ?

Staircase? I'm still in pain from the last time I tried to push it in a more palatable form via the plugsched architecture which took me a long time to do. I don't have the fortitude to go through that again in a hurry.

Cheers,
Con
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