pthread switch (was Odd KSE panic)
Daniel Eischen
eischen at vigrid.com
Mon Jul 5 16:55:49 PDT 2004
On Mon, 5 Jul 2004, Julian Elischer wrote:
> On Mon, 5 Jul 2004, Daniel Eischen wrote:
> >
> > It doesn't matter which thread gets run after the I/O thread
> > calls pthread_cond_signal(). Either way, the I/O thread has
> > to reenter the kernel and wait for the next event. And that
> > time adds to the latency of the worker thread the _next_ time.
>
> not assuming that the worker thread tries to see if there is more work
> before it yields.
>
> All I'm saying is that the app should decide the priority.
> and you agree that it would be quicker in the case of the
> 1KSE case?
Latency is reduced, but overall throughput(*) is also reduced
because of the extra thread switch for every wakeup.
(*) Assuming that events occur fast enough.
I'll have a look at adding preemption points, but I still have
my doubts that it really matters...
--
Dan Eischen
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