[Twisted-Python] high server loads on FreeBSD - does kqueue reactor help?

Maarten ter Huurne maarten at treewalker.org
Tue Jan 20 09:16:51 EST 2009

On Tuesday 20 January 2009, Werner Thie wrote:

> With a four core, four twisted http server processes (nevow/athena on
> top), dual 100 MBps interfaces, all four cores showing CPU loads of 50%
>   plus, I observe the following degradation in the network traffic with
> tcpdump:
> - 'TCP checksum incorrect' raising to almost 25% of all packets observed
>   from one client IP
> - TCP Ack'ed lost segment raising to 0.5% of all packets observed

Incorrect checksums sounds like a hardware problem. Or possibly a driver 
problem if the checksum calculation is done by the CPU instead of the 
network card. In any case it is not possible for user space code like 
Twisted to generate incorrect TCP checksums.


More information about the Twisted-Python mailing list