em0 performance subpar

[Jack Vogel]

My validation engineer set things up on an 8.2 REL system, testing the
equivalent of
HEAD, and he reports performance is fine. This is without any tweaks from
what's
checked in.

Increasing the descriptors to 4K is way overkill and might actually cause
problems,
go back to default.

He has a Linux test client, what are you transmitting to?

Jack


On Thu, Apr 28, 2011 at 11:00 AM, Adam Stylinski <kungfujesus06 at gmail.com>wrote:

> On Thu, Apr 28, 2011 at 09:52:14AM -0700, Jack Vogel wrote:
> > Adam,
> >
> > The TX ring for the legacy driver is small right now compared to em, try
> > this experiment,
> > edit if_lem.c, search for "lem_txd" and change EM_DEFAULT_TXD to 1024,
> see
> > what
> > that does, then 2048.
> >
> > My real strategy with the legacy code was that it should stable, meaning
> not
> > getting
> > a lot of changes... that really hasn't worked out over time. I suppose
> I'll
> > have to try and
> > give it some tweaks and let you try it. The problem with this code is it
> > technically supports
> > a huge range of old stuff we don't test any more, things I do might cause
> > other regressions :(
> >
> > Oh well, let me know if increasing the TX descriptors helps.
> >
> > Jack
> Jack,
>
> Is this the same thing as adjusting these values?:
>
> hw.em.rxd=4096
> hw.em.txd=4096
>
> If so I've maxed this out and it's not helping.  I'll give it a shot on my
> 8-STABLE box as it has a kernel I can play with.
>
> Setting the MTU to 1500 gave lower throughput.
>
> --
> Adam Stylinski
> PGP Key: http://pohl.ececs.uc.edu/~adam/publickey.pub
> Blog: http://technicallyliving.blogspot.com
>