Dynamic coprocessor management for FPGA-enhanced compute platforms

Abstract

Various commercial programmable compute platforms have their processor architecture enhanced with field-programmable gate arrays (FPGAs). In a common usage scenario, an application loads custom processors into the FPGA to speed up application execution compared to processor-only execution. Transient applications, changing application workloads, and limited FPGA capacity have led to a new problem of operating-system-controlled dynamic management of the loading of coprocessors into the FPGAs for best overall performance or energy. We define the Dynamic Coprocessor Management problem and provide a mapping to an online optimization problem known as Metrical Task Systems. We introduce a robust heuristic, called the fading cumulative benefit (FCBenefit) heuristic, that outperforms other heuristics, including a previously developed one for MTS. For two distinct application sets, we generate numerous workloads and show that the FCBenefit heuristic provides best results across all considered workloads. In our simulations, the heuristic's results were within 9% of the offline optimal for performance, and within 3% for energy. The heuristic may be applicable to a wide variety of dynamic architecture management problems.