Subject: Re: POSIX.4 real-time extensions?
To: =?X-UNKNOWN?Q?Jarom=EDr_Dolecek?= <>
From: Alex Barclay <>
List: tech-kern
Date: 07/06/2001 08:58:46
On Fri, 6 Jul 2001, Jarom=EDr Dolecek wrote:

> > a real aio implementation would expose maximum parallelism to the
> > underlying hardware i/o system.
Absolutely. I saw a linix impl which fronted each aio request with a user
space thread then muxed everything down to poll/select yeuch. One of my
apps frequently holds about 60000 socket connections open with each
connection lasting about 3 minutes with maybe 150Kb of data passed.

> How do other OS manage this, e.g. Solaris? (It seems Linux doesn't suppor=
> this, at least I can't find any mention of aio in 2.3.49 kernel sources).

I'm not sure about Solaris but in HP-UX there seems to be a kernel tunable
for the max aio requests allowed system wide. I've typically been setting
this to about 131072 and do not seem to be experiencing any particular

A BSD implementation should also be able to handle this number of
simultaneous aio requests which may be a problem if you have a pool of