Re: Network Performance?

[Tim Sailer]

On Thu, Jan 04, 2001 at 01:33:40AM -0500, Tim Sailer wrote:
> This may not be the right forum to ask this. If not, please let me know
> where to ask.
> 
> I have a Debian box with 2 NICs. Both 100/full duplex. This machine is 
> running as a ftp proxy (T.Rex suite). As part of the traffic going through the
> box, some streams have 1000k window size for a certain reason. How do
> I tune the NICs to handle the streams better? There are ways of doing this
> on other OSs. Right now, the box only does about 1.8Mb when it should be doing
> 80+Mb.
> 
> Thanks,
> Tim
> 
> PS: This is really something to do with the window size and WAN latency.
> The ultimate source and destination points are either Solaris or AIX
> boxes. The files being sent are > 1GB in size.
> The box does well when traffic goes in one NIC and out the other, as long
> as the end point is local When it hits the WAN, it all dies. Traffic not
> going through the box just flies right along, as long as both the end points
> have the large tcp window size. Putting the Linux box in the middle is a 
> severe choke point. :(

I have followed the suggestions in http://www.psc.edu/networking/perf_tune.html
but I still can not get any kind of real throughput. 250kB is all I can
get from the Linux box. Setting [r|w]mem_[default|max] larger than 16k
makes no difference, smaller slows things down even more. Has anyone else
ran across this and fixed it? I can't be the only one with a Linux box
on a fat pipe looking for maximum throughput...

Tim

-- 
Tim Sailer <[e-mail]> Cyber Security Operations
Brookhaven National Laboratory  [phone]