[ixp1200] Threads

Hi I am using the IXP1200 Eval platform to run a routing and forwarding program. One of the threads simply forward packets and the other sends out generated packets. When I run the code on the hardware, I notice that the first thread gets swapped out and does not run. I also ran the l3fwd_16_RFC1812 example code on the hardware and noticed that the thread is swapped out in that too. The programs run great when I use the simulator and I am not able to find out what is different on the hardware. Could somebody help me out here? Thanks in advance. Shruti