Messages in this thread |  | | Date | Wed, 14 Nov 2001 10:08:04 -0800 (PST) | From | Davide Libenzi <> | Subject | Re: [patch] scheduler cache affinity improvement for 2.4 kernels |
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On Tue, 13 Nov 2001, Mike Kravetz wrote:
> On Thu, Nov 08, 2001 at 03:30:11PM +0100, Ingo Molnar wrote: > > > > i've attached a patch that fixes a long-time performance problem in the > > Linux scheduler. > > Just got back from holiday and saw this patch. I like the idea > slowing down task dynamic priority modifications (the counter > field). My only thought/concern would be in the case where a > task with maximum dynamic priority (counter value) decides to > use 'all' of its timeslice. In such a case, the task can not > be preempted by another task (with the same static priority) > until its entire timeslice is expired. In the current scheduler, > I believe the task can be preempted after 1 timer tick. In > practice, this shouldn't be an issue. However, it is something > we may want to think about. One simple solution would be to > update a tasks dynamic priority (counter value) more frequently > it it is above its NICE_TO_TICKS value.
Mike, take a look at my next post in this thread. I'm using a watermark value of 10 :
if (p->counter > TICKS_WMARK) --p->counter; else if (++p->timer_ticks >= p->counter) { p->counter = 0; p->timer_ticks = 0; p->need_resched = 1; }
- Davide
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