4.2.2. Normal scheduling policies

There are three normal scheduling policies: SCHED_OTHER, SCHED_BATCH and SCHED_IDLE. However, the SCHED_BATCH and SCHED_IDLE policies are intended for very low priority jobs, and as such are of limited interest in a performance tuning guide.
The default scheduling policy. This policy uses the Completely Fair Scheduler (CFS) to provide fair access periods for all threads using this policy. CFS establishes a dynamic priority list partly based on the niceness value of each process thread. (Refer to the Deployment Guide for more details about this parameter and the /proc file system.) This gives users some indirect level of control over process priority, but the dynamic priority list can only be directly changed by the CFS.