Messages in this thread | | | Date | Tue, 14 Sep 2004 23:33:48 +1000 | From | Nick Piggin <> | Subject | Re: [patch] sched: fix scheduling latencies for !PREEMPT kernels |
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Ingo Molnar wrote: > * Nick Piggin <nickpiggin@yahoo.com.au> wrote: > > >>Could these ones go up a level? We break down scanning into 32 page >>chunks, so I don't think it needs to be checked every page. > > > not really - we can occasionally get into high latencies even with a > single page - if a single page is mapped by alot of processes. >
So doing it in the loop doesn't really give you a deterministic maximum latency if somebody is out to cause trouble, does it?
OTOH, I guess libc or some shared memory segment may be mapped into a lot of processes even on RT applictions.
Another thing, I don't mean this to sound like a rhetorical question, but if we have a preemptible kernel, why is it a good idea to sprinkle cond_rescheds everywhere? Isn't this now the worst of both worlds? Why would someone who really cares about latency not enable preempt? - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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