What to adapt in a high-performance microprocessor

Abstract

High-performance processors usually require large amounts of power for their operation. Adapting resources in such processors is very relevant as each application and distinct use of the system has a different demand. A frequent use of adaptation is to have the processor operating in either high-performance or low-power mode. In this work we analyze how power and performance change while modifying most of the resources in a processor. This leads to identifying which resources are more important for adaptation. This analysis was performed for three distinct workloads: multimedia, scientific, and database. Four criteria were defined to limit the adaptation range considering the cost and/or the efficiency of the system. The results of our experiments showed that the resource to be adapted depends on the: (1) operating mode (e.g. low-power or high-performance), (2) the workload, and (3) the criteria. Overall, for our baseline processor configuration, the dominant resources to be adapted are the voltage-frequency and the first-level instruction cache. Adapting resources may lead to an increase in the performance by up to 44% or a reduction in power by up to 93% with no restrictions. For configurations of the same cost and efficiency as the baseline, adaptation of resources may improve the performance by 33% or reduce the power by 34%.