Sticky-ERfair: a task-processor affinity aware proportional fair scheduler

Abstract

A drawback of current proportional fair schedulers is that they ignore task-to-processor mutual affinities, thereby causing frequent inter-processor task migrations and cache misses. This paper presents the Sticky-ERfair Scheduler, an Early-Release Fair (ERfair) scheduler that attempts to minimize task migrations and preemptions. Given any processor V i , Sticky-ERfair allocates to it the most recently executed ready task that previously executed on V i (thus restricting migrations and preemptions) in such a way that this allocation does not cause any ERfairness violations in the system at any time during the schedule length. Experimental results reveal that Sticky-ERfair can achieve upto over 40 times reduction both in the number of migrations and preemptions suffered with respect to Basic-ERfair (for a set of 25 to 100 tasks running on 2 to 10 processors) while simultaneously guaranteeing ERfairness at each time slot.