Multthreading with netfilter?

I need to do difficult processing of IP packets. For speed up, I want
to process parts of packets in different kernel threads.
I start n threads (n = CPU count -1) in module initialization part,
and make them waiting (I use semaphores and self-made queue). At
nf_hook I
add tasks to queues and up() threads. As I in atomic context in
nf_iterate, I do in main thread computations, and then wait for
threads done with while() loop without scheduling. The problem is:
other threads sometimes don't wake up after up(). Sometimes, when I
press Enter key (SIC!) threads wake up, sometimes not.

Is there any right solvation for this problem?