Messages in this thread | | | From | Con Kolivas <> | Subject | Re: Network slowdown from 2.6.7 to 2.6.9 | Date | Wed, 17 Nov 2004 11:37:13 +1100 |
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Stephen Hemminger writes:
> On Tue, 16 Nov 2004 15:46:25 -0800 > Harry Edmon <harry@atmos.washington.edu> wrote: > >> I have a system that is running a program that receives and sends >> atmospheric data via TCP. Most of the data is either in little packets >> (between 64 and 127 bytes) and large packets (between 1024 and 1517). I >> am running this on a dual Xeon box (Tyan S2721-533 motherboard) with 2 >> GB of memory and a Intel gigabit ethernet (82546EB). I have been >> running this under 2.6.7. When I switch to 2.6.9 on the same hardware, >> my network throughtput is cut by more than half. All I can tell from >> looking at "netstat -s" is that my TCP resets are orders of magnitude >> higher under 2.6.9 than 2.6.7. Enclosed is my 2.6.7 and 2.6.9 config >> files. Anyone have any ideas where I should look to find the problem? > > Do an OpenBSD or other firewall in the way that doesn't understand window > scaling? OpenBSD pf doesn't correctly TCP window scaling so it ruins the > throughput (typically 1/4 of expected).
Easiest way to see if this is responsible is to disable it and see if the throughput improves
echo 0 > /proc/sys/net/ipv4/tcp_window_scaling
Cheers, Con
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