Re: Trying out SCHED_BATCH

[Con Kolivas <kernel@kolivas.org>]

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