[Samba] AIO settings

[Jeremy Allison]

On Wed, Jul 27, 2005 at 04:37:07PM -0400, William Jojo wrote:
> 
> /*
>  * sigevent structure, referred to (but not used) in asynchronous i/o.
>  *
>  * WARNING: The unix98 sigevent is available to user programs, but this
>  *          does not itself guarantee that the kernel supports unix98 aio.
>  *
>  */
> 
> Real-time signals in aio are not supported....yet...So now my question is
> can we do this another way?

No. Polling would be a complete waste of time (IMGO).

> I'm mocking up a process_aio_queue that doesn't use the signal portion but
> I'm having a hard time linking it to async_processing() which appears to
> be linked to oplock handling (or if you have another
> preference/recommendation).

There's no good way to fix this without signals - Samba may wait in select
or up to 30 seconds or so for an incoming smb request, if this was filled
with polling for aio completion you might as well be running DOS.

> I've set up a test with aio and hundreds of aiocb's of 64K in flight,
> without the signal processing and it's working great in my test bed.
> 
> What I'd like to do is trip the async_processing() more frequently and put
> more mid's in flight or some variation thereof as the smbd code path will
> allow. Do you have any pointers on achieving such a goal?

IBM needs to fix the AIX kernel so this works correctly.

Jeremy.