The fact that your cpu usages jumps up is good. You generally want to use your cpu as much as possible, as that means you're not waiting on network traffic.

On the other hand:

1. Unless you're on Windows, you do not get 1 process, you'd get a process for each fork(), meaning 10 processes in this case.

2. Each child process will take a finite amount of memory. ForkMananger should keep the number of processes limited and memory should be reclaimed when the forked() child is exiting. Memory usage shouldn't increase indefinitely.

My guess: you're running on windows, and perl's fork() emulation is giving you trouble. It's possible that using threads may work a little better in that case.