em0 NIC slow on 8.2-p1 amd64?

Michael W. Lucas mwlucas at blackhelicopters.org
Fri Jul 22 19:08:30 UTC 2011

On Fri, Jul 22, 2011 at 02:06:23PM -0400, Mike Tancsa wrote:
> On 7/22/2011 1:50 PM, Eduardo Morras wrote:
> > At 17:12 21/07/2011, Michael W. Lucas wrote:
> >> On Thu, Jul 21, 2011 at 05:01:57PM +0200, Eduardo Morras wrote:
> >> >
> >> > Have you tried other protocols? Http, rsync... It maybe a problem at
> >> > client side, some ftp clients can set a maximun ftp transfer, like
> >> > filezilla, winscp,
> >>
> >> FTP and NFSv3 both have similar results.
> >>
> >> ==ml
> > 
> > Perhaps you have reached the maximum disk speed. Sorry not more ideas,
> > but it doesn't look like a nic problem. Put the file in cache before
> > sending it. If it's faster the problem is a bottleneck on hard disk or
> > sata/ata/usb bus.
> What if you do a fetch -o /dev/null {http|ftp}://remotesite/file
> and see what speeds you get. That would get rid of the disk as an io issue

Good idea.

fetch -o /dev/null ftp://xxx/ftp/FreeBSD-9.0-CURRENT-201011-amd64-dvd1.iso
/dev/null                                     100% of 1027 MB   29 MBps 00m00s

Basically the same.  I don't think it's disk.

There's kern/152828 claiming a performance regression with em under
8.2, but I'm not sure if that is applicable to my system. I'd upgrade
the kernel to test, but I'm not brave enough to downgrade the kernel
to 8.0 for comparison. (I've never had good luck running an old kernel
on a new userland.)


Michael W. Lucas 	
http://www.MichaelWLucas.com/, http://blather.MichaelWLucas.com/
Latest book: Network Flow Analysis http://www.networkflowanalysis.com/
mwlucas at BlackHelicopters.org, Twitter @mwlauthor

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