On-Line Hard Real-Time Scheduling of Parallel Tasks on Partitionable Multiprocessors

Until now little research has addressed the problem of on line scheduling of sporadic parallel tasks with hard deadlines in partitionable multiprocessor systems In this paper we present two on-line scheduling algorithms - Buddy/RTand Stacking, for such environments Both the algorithms either guarantee or reject a task at the time of its arrival Buddy/RT is a straight-forward extension of the well-known Buddy strategy to the real-time environment, while Stacking is a more sophisticated algorithm based on the lessons learned from Buddy/RT The underlying concept behind the Stacking algorithm is to reduce fragmentation by ´stacking´ equal-sized jobs in the time dimension The Stacking algorithm is found to perform significantly better than Buddy/RT over a wide range of workloads, even though both the algorithms have the same time complexity