Re: New driver mtipx2xx submission

[Jeff Moyer <jmoyer@redhat.com>]

Alan Cox <alan@lxorguk.ukuu.org.uk> writes:

>> Anywho, a 40% difference is pretty significant (though NUMA can have
>> that sort of impact).  Alan, what do you think?  I was never clear on
>> how exactly the ahci driver would handle a queue depth larger than 32
>> (if it can't, then clearly we'd need a block driver for this hardware).
>
> The AHCI driver can drop that support in fairly easily all the queue
> handling is nicely pluggable.
>
> A 40% improvement is a big win, but it seems to me that if any of that is
> not hardware related (ie the bigger command queue) then we need to be
> fixing the existing driver to improve *ALL* AHCI devices. Or are we going
> to end up with a pile of AHCIish drivers for every random device on the
> planet ?

The 40% number was for a queue depth of 32, so yes, there's room for
improvement in AHCI (so long as it isn't related to the block layer's
rq_affinity interacting poorly with NUMA or some such thing).

> My request for info on the Micron errata has so far been ignored,
> questions on what is involved in the queue stuff likewise. I'd like to
> see those matters resolved.

Asai?

-Jeff