The Effect of Core Number and Core Diversity on Power and Performance in Multicore Processors

Abstract

Today, multi-core processors dominate server, desktop and notebook computer’s market. Such processors have been able to decrease power consumption and thermal challenges that designers face within single core processors. In order to improve multi-core processor’s performance, designers should choose the best set of cores based on power consumption and execution delay. In this paper, we study several architectures that are composed of a configurable number of cores. We use three cores with different levels of performance and power consumption. Then, we implement different configurations of a multi-core processor. In each configuration, which has a different set of cores, we run benchmarks with various numbers of simultaneous threads, from 1 up to 32. Power consumption and execution delay of each configuration has been measured. It has been shown that the best configuration is a heterogeneous multi-core processor that is composed of 16 cores in our bounded area. Then, we examined various ways that threads can be assigned to different cores in the best configuration. It is shown that for serial workloads the best choice is to use high performance cores, but in parallel workloads that consist of multiple threads, a mixture of cores with different performance levels gives the best performance.