Re: Readiness vs. completion (was: Re: Linux's implementation ofpoll()not scalable?)

[Dan Kegel <dank@alumni.caltech.edu>]

John Gardiner Myers wrote:
> 
> Dan Kegel wrote:
> > IMHO you're describing a situation where a 'completion notification event'
> > (as with aio) would be more appropriate than a 'readiness notification event'
> > (as with poll).
> 
> I've found that I want both types of events, preferably through the same
> interface.  

That's good to know.

> To provide a "completion notification event" interface on
> top of an existing nonblocking interface, one needs an "async poll"
> mechanism with edge-triggered events with no event coalescing.

If you have a top-notch completion notification event interface
provided natively by the OS, though, does that get rid of the
need for the "async poll" mechanism?
 
> You are correct in recognizing NT completion ports from my description.
> While the NT completion port interface is ugly as sin, it gets a number
> of performance issues right.
> 
> > And, come to think of it, network programmers usually can be categorized
> > into the same two groups :-)  Each style of programming is an acquired taste.
> 
> I would say that the "completion notification" style is a paradigm
> beyond the "readiness notification" style.  I started with the select()
> model of network programming and have since learned the clear
> superiority of the "completion notificatin" style.

Both seem to have their place, and deserve good support, IMHO.

- Dan
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