Make the foreground process I/O-bound

1.

Modify loop so that instead of being CPU-bound it is I/O-bound. You can check by running the program on an idle machine and checking the percentage of CPU it uses. If it is significantly below 100%, it is probably because it is spending lots of time waiting for I/O.

2.

Run your experiments again (or a subset of them--you don't have to be exhaustive), and see what effect a background job has on the performance of I/O-bound jobs.