Netfilter and SMP

Netfilter and SMP

[Majid Khan]

Hi,
  I am developing a netfilter based application on an SMP (AMD 64;dual
core) system (kernel 2.6).
One thing that I noticed over a period of time was that most of the
network traffic was handled by only one of the processor. Only under
high network traffic (roughly 10,000 packet/sec or more) did the
second processor got invloved invloved in traffic handling. Even then
more than 90 percent of the traffic was being handled by one of the
processor.

Can somebody provide me with some information on how to configure my
SMP system so that both processors share the network traffic load.

My second question was that if there is any known method to gracefully
handle failures in a netfilter module. Currently any failure in
netfilter would cause the kernel panic.

Regards,
Majid

Re: Netfilter and SMP

[Andi Kleen]

> Can somebody provide me with some information on how to configure my
> SMP system so that both processors share the network traffic load.

You would need multiple active incoming network interfaces. 
Linux right now doesn't support load balancing from a single interrupt.
Even if it did that would likely require hardware support for MSI-X.

> My second question was that if there is any known method to gracefully
> handle failures in a netfilter module. Currently any failure in
> netfilter would cause the kernel panic.

Write a user space module using nf queue? 

-Andi