Messages in this thread | | | Date | Fri, 23 Jul 2004 16:45:23 +1000 | From | Nick Piggin <> | Subject | Re: [linux-audio-dev] Re: [announce] [patch] Voluntary Kernel Preemption Patch |
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Ingo Molnar wrote: > * Nick Piggin <nickpiggin@yahoo.com.au> wrote: > > >>>this doesnt work either: once we've committed ourselves to do an >>>'immediate' softirq processing pass we are risking latencies. We cannot >>>preempt the idle task while it's processing softirqs the same way we can >>>do the lock-break if they are always deferred. >>> >> >>It is a preempt off region no matter where it is run. I don't see how >>moving it to ksoftirqd can shorten that time any further. > > > look at my latest patches to see how it's done. We can preempt softirq > handlers via lock-break methods. The same method doesnt work in the idle
Are you referring to this patch? http://people.redhat.com/mingo/voluntary-preempt/defer-softirqs-2.6.8-rc2-A2
Surely something similar could easily be done for irq context softirq processing with a patch like my earlier one? And it would prevent spilling to ksoftirq when a RT thread isn't waiting to run.
> thread. With this method i've reduced worst-case softirq latencies from > ~2-4 msecs to 100-200 usecs on a 2GHz x86 box. >
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