Re: Status of AIO

[Nicholas Miell <nmiell@comcast.net>]

On Tue, 2006-03-07 at 03:30 +0200, Dan Aloni wrote:
> On Mon, Mar 06, 2006 at 04:18:54PM -0500, Benjamin LaHaise wrote:
> > On Mon, Mar 06, 2006 at 08:24:03AM +0200, Dan Aloni wrote:
> > > Hello,
> > > 
> > > I'm trying to assert the status of AIO under the current version 
> > > of Linux 2.6. However by searching I wasn't able to find any 
> > > indication about it's current state. Is there anyone using it
> > > under a production environment?
> > 
> > For O_DIRECT aio things are pretty stable (barring a patch to improve -EIO 
> > handling).  The functionality is used by the various databases, so it gets 
> > a fair amount of exercise.
> > 
> > > I'd like to know how complete it is and whether socket AIO is
> > > adaquately supported.
> > 
> > Socket AIO is not supported yet, but it is useful to get user requests to 
> > know there is demand for it.
> 
> Well, I've written a small test app to see if it works with network
> sockets and apparently it did for that small test case (connect() 
> with aio_read(), loop with aio_error(), and aio_return()). I thought 
> perhaps the glibc implementation was running behind the scene, so I've 
> checked to see if it a thread was created in the background and I 
> there wasn't any thread. 

None of the aio_* functions use the kernel's AIO interface. They're
implemented entirely in userspace using a thread pool.

-- 
Nicholas Miell <nmiell@comcast.net>