A technique for defragmenting jobs on processor-based computing resources including: (i) determining a first defragmentation condition, which first defragmentation condition will be determined to exist when it is favorable under a first energy consideration to defragment the allocation of jobs as among a set of processor-based computing resources of a supercomputer (for example, a compute-card-based supercomputer); and (ii) on condition that the first defragmentation condition exists, defragmenting the jobs on the set of processor-based computing resources.