cpu usage

[6bone%6bone.informatik.uni-leipzig.de@localhost]

hello,

at my system (NetBSD 5.0_STABLE amd64) are running some perl based 
simulations. The server has 16G ram and 71G swap. When a process is using 
more than 16G ram, the system swaps. But sometimes it looks as if anything 
is blocked. The simulation process is only using 3% CPU time, 96.8% idle, 
0.1% system, 0.1% interrupt. The system load is near 1.10. Iostat shows 
no significant disk i/o. The simulation process has the state biowait.

Can you give me some hints why the process does not get more CPU? Because 
of the low disk i/o it does not seam to be blocked by swap i/o.

Thank you for your efforts.
Uwe