Messages in this thread | | | Date | Mon, 01 Apr 2013 12:36:52 +0530 | From | Preeti U Murthy <> | Subject | Re: [PATCH 4/5] sched: don't consider upper se in sched_slice() |
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Hi Joonsoo,
On 04/01/2013 09:38 AM, Joonsoo Kim wrote: > Hello, Preeti. >
>> >> Ideally the children's cpu share must add upto the parent's share. >> > > I don't think so. > > We should schedule out the parent tg if 5ms is over. As we do so, we can > fairly distribute time slice to every tg within short term. If we add > the children's cpu share upto the parent's, the parent tg may have > large time slice, so it cannot be preempted easily. There may be a latency > problem if there are many tgs.
In the case where the #running < sched_nr_latency, the children's sched_slices add up to the parent's.
A rq with two tgs,each with 3 tasks.
Each of these tasks have a sched slice of [(sysctl_sched_latency / 3) / 2] as of the present implementation.
The sum of the above sched_slice of all tasks of a tg will lead to the sched_slice of its parent: sysctl_sched_latency / 2
This breaks when the nr_running on each tg > sched_nr_latency. However I don't know if this is a good thing or a bad thing.
Regards Preeti U Murthy
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