em0 performance subpar

[Adam Stylinski]

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
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 834 bytes
Desc: not available
Url : http://lists.freebsd.org/pipermail/freebsd-net/attachments/20110428/3c647189/attachment.pgp