Computing Resources

Lengthy calculations ( >> few minutes), in particular treatment planning, should be run in background (batch) mode. This allows fair and more efficient use of computing resources, because a scheduling system called LoadLeveler automatically locates eligible idle CPUs and assigns work to them. This way "overcrowded" and "unemployed" machines can be avoided.

You use the LoadLeveler by submitting a command file describing your requirements (in memory and CPU time by selecting a job class ) as well as specifying the program to run and the destination of the stdin, stdout, stderr streams. Essentially it is not much different from working with the command line and nohup, but a lot more efficient. A commented example for a command file is here You may use either the Motif-based graphical tool xloadl or a handful of shell commands to control job execution, e.g.:
llsubmit ll.cmd
submits a job defined in command file ll.cmd
lists all active jobs and
llcancel biors6a.4287.0
llcancel -u bioguest
cancels the specified job or all jobs of user bioguest, respectively.
A documentation of LoadLeveler can be found as HTML and PDF.

Job Classes

Here's the current definition of job classes on the bio* AIX machines, with their upper memory and CPU time limit.

Classes bioshort biomedium biolong biolarge biovlarge biohuge
Memory 128 MByte  256 MByte  256 MByte  2 GByte  3.25 GByte  8 GByte 
Time 15 m  1 h  24 h  72 h  72 h  72 h 

Note that these times are calibrated against the workhorse Power4+ machines (biops6a,b,z). Jobs on slower machines are allotted more time according to their relative speed.
Last updated: 20-Apr-2005, M.Kraemer

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