Re: POSIX aio vs completion ports

Chuck Lever (cel@monkey.org)
Tue, 14 Sep 1999 14:31:47 -0400 (EDT)

On Mon, 13 Sep 1999, Jordan Mendelson wrote:
> John Gardiner Myers wrote:
>
> > * Chuck Lever informs me that the signal queue might overflow, leading
> > to lost completion notifications. There is no reasonable way for an
> > application to recover from such a condition.
>
> As far as I know, on a queue overflow, SIGIO is raised and you can select() or
> poll() on your fds. This of course is going to be exceptionally slow on a
> large number of descriptors, but it shouldn't happen often.

i think that kind of design is completely unrealistic. you are most
likely to run out of queue space when the server is overloaded. why then
would you want to use a recovery mechanism that would just make the
overload worse? the server is better off ignoring queue overflow.

- Chuck Lever

--
corporate:	<chuckl@netscape.com>
personal:	<chucklever@netscape.net> or <cel@monkey.org>


The Linux Scalability project:
	http://www.citi.umich.edu/projects/linux-scalability/




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