On Sun, 12 Mar 2000 yodaiken@fsmlabs.com wrote:
> > Quite regardless of how you do interrupts: it doesn't matter where youput
> > the ACK's, you always need to make sure that irq masking etc is correct,
> > and you must NOT allow a context switch while an interrupt handler is
> > still running.
>
> Ok. Ingo: does your "low latency" patch violate this rule?
yep, of course. It's a grave error to schedule during IRQ contexts, and we
do have an assert in schedule() so it's plain impossible. The lowlatency
patch simply works by increasing the effective frequency (occurance) of
rescheduling (preemption) points [without actually rescheduling more
often].
Having said this, i now do agree that doing a preemptible kernel (which
the Linux SMP kernel could become with a small amount of work) is a
superior solution to this, wrt. latencies.
Ingo
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This archive was generated by hypermail 2b29 : Wed Mar 15 2000 - 21:00:24 EST