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SubjectRe: Signal driven IO
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> > Benchmark it for your application. For web and ftp traffic the I/O signals
> > are a clear winner.
>
> A clear winner regardless of how many file desciptors are ready per "loop
> pass"? Surely there has to be some number at which poll becomes superior.
> Certainly with artificial cases where you overload the CPU and deliberately
> hit multiple links at the same time.


Web traffic is very large numbers of slow operations. Your ration of
busy/queued is low. I'd agree there should be a point where you have a lot of
busy operations but web/ftp isnt it.

On a T1 you can expect to see 600 parallel connections. Each is averaging
2 or 3 K a second with a typical 1500 byte MTU. So each FD wakes one or two
times a second.

So we have 1200 wakeup events per second over 600 handles. Even at 100polls/sec
that means we get 12 positive handles and 588 overheads per poll. As it rises
to the real world values its hits 1 and 599 overhead at 1000 polls/sec

Alan



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