CPU limiting is implemented by giving each jail a (user-changeable) number of CPU shares and tracking the estimated CPU usage of the tasks that run in that jail. If the ratio of the jail's estimated CPU usage to total CPU usage exceeds the ratio of the jail's CPU shares to total CPU shares outstanding, the jailed processes have their priorities decreased until the ratio of actual usage (estimated CPU) drops below permitted usage (shares). Unjailed processes are not subject to this regime.

• jtune program to modify CPU and memory limits on running jails

• Write / update man pages for jtune, jail

• Make memory limiter stop paging when jail is under limit