Re: Network slowdown from 2.6.7 to 2.6.9

[Harry Edmon <harry@atmos.washington.edu>]

Tried your suggestion - no improvement.

Con Kolivas wrote:

> 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