Coordinated Thread Scheduling for Workstation Clusters Under Windows NT

Coordinated thread scheduling is a critical factor in achieving good performance for tightly-coupled parallel jobs on workstation clusters. We are building a coordinated scheduling system that coexists with the Windows NT scheduler which both provides coordinated scheduling and can generalize to provide a wide range of resource abstractions. We describe the basic approach, called "demand-based coscheduling", and implementation in the context of Windows NT. We report preliminary performance data characterizing the effectiveness of our approach and describe benefits and limitations of our approach. 1. Introduction Coordinated scheduling for parallel jobs across the nodes of a multiprocessor is well-known to produce benefits in both system and individual job efficiency [1, 5, 6]. Without coordinated scheduling, parallel jobs suffer high communication latencies between constituent threads due to context switching. This effect is exacerbated if the thread scheduling for individual nodes is..