Ubuntu Unleashed 2015 Edition: Covering 14.10 and 15.04, Tenth Edition

Setting Processes Priority with nice

You can set the priority for individual processes, to tell the kernel to either limit or give extra priority to a specific process. This is most useful when multiple concurrent processes are demanding more resources than are actually available, since this is the condition that generally causes slowdowns and bottlenecks. Processes set with a higher priority get a larger portion of the CPU time than lower priority processes.

You can set this priority when you first run a program by putting the command nice before whatever you are going to run, and assigning the process a value that designates its priority. By default, all processes start with a priority of 0 (zero). nice can set that to a maximum of -20, which ...