Improving system performance in contiguous processor allocation for mesh-connected parallel systems

Abstract

Fragmentation is the main performance bottleneck of large, multiuser parallel computer systems. Current contiguous processor allocation techniques for mesh-connected parallel systems are restricted to rectangular submesh allocation strategies causing significant fragmentation problems. This paper presents an L-shaped submesh allocation (LSSA) strategy, which lifts the restriction on the rectangular shape formed by allocated processors in order to address the problem of fragmentation. LSSA can manipulate the shape of the required submesh to fit into the fragmented mesh system. As other strategies, LSSA first tries to allocate the conventional rectangular submeshes. If it fails, LSSA further tries to allocate more flexible L-shaped submeshes instead of signaling the allocation failure. Thus, LSSA accommodates incoming jobs faster than other strategies and results in the reduction of job response time. Extensive simulations show that LSSA performs more efficiently than other strategies in terms of the external fragmentation, the job response time and the system utilization.