Re: [boost] Re: Re: Boost.Thread : IO multiplexing

From: Jeremy Maitin-Shepard (jbms_at_[hidden])
Date: 2004-01-29 04:06:55

"Hurd, Matthew" <hurdm_at_[hidden]> writes:

>> On Behalf Of Sean Kelly
>> Subject: Re: [boost] Re: Re: Boost.Thread : IO multiplexing
>> 
>> IOCP works for both file and socket operations.  Perhaps not a poll
>> method but I'm not much interested in the low-end solutions anyway.

> Small point.  Please don't knock the pollster ;-)

> Polling trades CPU for latency gain.  Polling is a high end solution for
> low latency requirements, which covers a lot of my issues (not the
> psychological ones though ;-)).  Not so good for high throughput
> systems, but it can be.  A combined approach, poll for a while you can
> then wait for an interrupt ( a bit like spin-locks ), can be especially
> beneficial for supercomputer oriented frameworks as plenty of research
> shows.

While poll(2), like select(2), is indeed rather inefficient on many
platforms, other polling mechanisms, such as epoll, kqueue, and
/dev/poll can scale quite well.  On Windows platforms, I think it is
clear that asynchronous I/O is almost always more efficient than
polling, and I believe Sean Kelly, in recommending against polling, was
referring exclusively to Windows platforms.

> [snip]

-- 
Jeremy Maitin-Shepard