Re: Network slowdown from 2.6.7 to 2.6.9

Stephen Hemminger
2004-11-23T19:08:11Z

On Mon, 22 Nov 2004 15:38:16 -0800
Harry Edmon <harry@atmos.washington.edu> wrote:

> Tried them all - none of them helped. Use "ntop" I can see that my
> throughput on the Intel gigabit ethernet interface on the system maxes
> out at 15.2 Mbps with 2.6.9. With 2.6.7 it made it to 35 Mbps.
>
> Does anyone have any other suggestions as to what to look for to
> diagnose this problem?

Well, before the TSO changes, if TSO was enabled then TCP would not obey slow
start or do congestion control properly. Did you increase the TCP send/receive
buffers (sysctl's net.ipv4.tcp_rmem and net.ipv4.tcp_wmem)? You may just
be window limited. Also, 2.6.9 has TCP bugs with TSO that can cause panic's.
These have been fixed in 2.6.10-rc2.