If you are running a job on one of our Departmental Unix machines which uses either a lot of CPU or a lot of swap space (these often go together), then you should run the process at priority (`niceness') 19. At priority (`niceness') 19 your job will cause minimum problems to other users of the system -- particularly the person sitting at the keyboard.
All processes that are running when you are not sitting at the console of the workstation must be run at priority (`niceness') 19.
You can start a job with `niceness' 19 by giving a command of the form:
nice -19 command [ arguments ]
Do man nice to look at the manual pages for this command.
If a job is already running then you will have to use the renice command to change the `niceness' -- e.g. renice 19 9999, where 9999 is the process id (pid) of the process -- this number can be obtained by doing ps -aux
If you leave jobs running with a `niceness' of less than 19 -- i.e. with a priority higher than 19 -- then, in order to improve the system's performance for the other users, it may be necessary for computing support staff to terminate your job without consulting you.
If you have any enquiries that cannot be answered by looking at the Physics Computing Services page, then please contact pcs@physics.ucsb.edu
Last updated 1998/10/05