I recently upgraded my kernel from 2.6.34 to 2.6.35 and hit a strange performance problem that I think is in the networking drivers.

In short, some apps that use the network can spend about 5m in kernel for every 5s of userspace time.

I've set up oprofile on this kernel and run it but I have no idea how to read the output. Simply running opreport shows that 80% of the samples were in the kernel but I'm not sure where to go from there.

Can anyone help me dig a little deeper?