scheduler (sched_4bsd) questions

Julian Elischer julian at elischer.org
Sun Oct 3 13:03:36 PDT 2004


Stephan Uphoff wrote:
> On Sun, 2004-10-03 at 03:04, Julian Elischer wrote:
> 

>>regarding the ksegrp runq.
>>For some time I have wanted to split it into 3 queues and the
>>threads will move between them. (in the ksegrp sched-private section)
>>queue 1.. threads that are running
>>queue 2.. threads that are on the system run queue.
>>queue 3.. threads that do not yet have a slot.
>>
>>what do you think?
>>
>>it should simplify the slot counting stuff.
>>
> 
> 
> This would be neat.
> 
> Queue 3 needs to be sorted.....
> ... what is the maximum size of this queue ?

about 8000 on i386 :-/  one for every runnable thread in the
kernel for that ksegrp.
  Usually just a few.

I've been considerring using the standard run-queue code and using a system 
runqueue (i.e. 64 queues in prioity order) per ksegrp but it's a lot of 
overhead. I  guess we'll need some sort of tunable syste that is efficient for 
just a few threads and switches if it gets a lot.


> 
> 
> 	Stephan
> 
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