Balancing Parallel Applications on Multi-core Processors Based on Cache Partitioning

Abstract

Load balancing is an important problem for parallel applications. Recently, many super computers are built on multi-core processors which are usually sharing the last level cache. On one hand different accesses from different cores conflict each other, on the other hand different cores have different work loads resulting in load unbalancing. In this paper, we present a novel technique for balancing parallel applications for multi-core processors based on cache partitioning which can allocate different part of shared caches to different cores exclusively. Our intuitive idea is partitioning shared cache to different cores based on their workloads. That is to say, a heavy load core will get more shared caches than a light load core, so the heavy load core runs faster. We give 2 algorithms in this paper, initial cache partitioning algorithm (ICP) and dynamical cache partitioning algorithm (DCP). ICP is used to determine the best partition when application starting while DCP is used to adjust the initial partition based on the changes of load balancing. Our experiment results show that the running time can be reduced by 7% on average when our load balancing mechanism based on cache partitioning is used.