Increased Scheduling Quality by Utilizing the Flexibility of Malleable Jobs

To accomplish both, the demand of the users of parallel systems for a low response time and the ambition of the system maintainers for a high utilization, is hard to do. A high utilization normally results in long waiting times for the users’ jobs. An alternative to the standard jobs with fixed width are more flexible jobs models. They allow to change the job’s width at application start (moldable jobs) or even during execution (malleable jobs). We have analyzed the quality of schedules using job sets with moldable and malleable jobs and combinations of both. Tracefiles from supercomputer installations have been modified to contain varying fractions of moldable and malleable jobs. Using a special simulation environment for the more flexible job models the jobs have been scheduled virtually. The results show that using this job models both interest groups mentioned above can be pleased.