Producing high CPU load

Source: http://superuser.com/questions/443406/how-can-i-produce-high-cpu-load-on-a-linux-server#443409

This loads four cores as 100%:

for i in 1 2 3 4; do while : ; do : ; done & done

Stop the above with:

for i in 1 2 3 4; do kill %$i; done

Check on how its going with (no drives, 5 iterations over 5 seconds):

iostat -n 0 -c 5