[dpdk-dev] Symmetric RSS Hashing, Part 2

Matt Laswell laswell at infiniteio.com
Mon Mar 30 17:13:05 CEST 2015


That's really encouraging.  Thanks!

One thing I'll note is that if my reading of the original paper is
accurate, the 0x6d5a value isn't there in order to cause symmetry - other
repeated 16 bit values will do that, as you've seen.  What the 0x6d5a value
gets you is symmetry while preserving RSS's effectiveness at load spreading
with typical traffic data.  Not all 16 bit values will do this.

--
Matt Laswell
infinite io, inc.
laswell at infiniteio.com

On Mon, Mar 30, 2015 at 10:00 AM, Vladimir Medvedkin <medvedkinv at gmail.com>
wrote:

> Matthew,
>
> I don't use any special tricks to make symmetric RSS work. Furthermore, it
> works not only with 0x6d5a.
>
> Regards,
> Vladimir
>
> 2015-03-28 23:11 GMT+03:00 Matthew Hall <mhall at mhcomputing.net>:
>
> > On Sat, Mar 28, 2015 at 12:10:20PM +0300, Vladimir Medvedkin wrote:
> > > I just verify RSS symmetric in my code, all works great.
> > > ...
> > > By the way, maybe it will be usefull to add softrss function in DPDK?
> >
> > Vladimir,
> >
> > All of this is super-awesome code. I agree having SW RSS would be quite
> > nice.
> > Then you could more easily support things like virtio-net and other stuff
> > which doesn't have RSS.
> >
> > Did you have to use any special tricks to get the 0x6d5a to work? I
> wasn't
> > quite
> > sure how to initialize that and get it to run right.
> >
> > Matthew.
> >
>


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