Subject: Re: multiple rx/tx rings and interrupt delivery on newer nics
To: Darren Reed <darrenr@netbsd.org>
From: Allen Briggs <briggs@netbsd.org>
List: tech-net
Date: 06/13/2007 10:11:29
On Wed, Jun 13, 2007 at 01:12:23AM -0700, Darren Reed wrote:
> Has anyone started to think about how NetBSD can take advantage
> of NICs that have a larger number of rx/tx descriptor rings,
> and/or MSI interrupts?

I've given larger # of rx/tx rings a little bit of thought, but
haven't come up with any good general-purpose way to make use
of them.

For one application, I'd have liked to have had multiple tx
rings for handling normal traffic and high-priority traffic (for
"application"-level exception/flow handling).  But the hardware
in question there doesn't offer multiple tx rings.

Different hardware has different kinds of packet classification
for incoming packets and probably different kinds of scheduling
for outgoing queues.  Is there prior art in some kind of general
purpose API to utilize these?

I'd be interested to hear if anyone's started thinking about MSI,
too, but that's not really a tech-net issue so much as a tech-kern
issue.

-allen

-- 
Allen Briggs  |  http://www.ninthwonder.com/~briggs/  |  briggs@ninthwonder.com