Max CPU load in *nix
Use the stress utility to generate a CPU load on your system.
Something like:
[root@xt ~]# stress --cpu 8
stress: info: [1009156] dispatching hogs: 8 cpu, 0 io, 0 vm, 0 hdd
What exactly are you interested in testing?
100% / 8 = 12.5. You're maxing out only one of your 8 possible cores. Run a multi-threaded program.