HetSim: A Simulator for Task-based Scheduling on Heterogeneous Hardware
Marcel Lütke Dreimann, Daniel Friesel, Olaf Spinczyk · 2024
Server hardware is becoming more and more heterogeneous, with an increasingly diverse landscape of accelerators such as GPUs, FPGAs, or novel processing-in-memory (PIM) technologies. Designing and evaluating scheduling algorithms for these is far from trivial due to accelerator-specific setup costs, compute capabilities, and other characteristics. In fact, many existing scheduling simulators only consider some of these characteristics, or only support a specific sub-set of accelerators. To overcome these challenges, we present HetSim, a modular simulator for task-based scheduling on heterogeneous hardware. HetSim enables research on online and offline scheduling and placement strategies for modern compute platforms that combine CPU cores with multiple GPU, FPGA, and PIM accelerators. It is efficient, fair, and compatible with a variety of common workload descriptions, output metrics, and visualization tools. We use HetSim to reproduce results from Alebrahim et al., and examine how accelerator characteristics affect the performance of various scheduling strategies. Our results indicate that ignoring accelerator characteristics during simulation is often detrimental, and that the ideal scheduling algorithm for a given workload may depend on available accelerators and their characteristics. HetSim is available as open-source software.