Priority-Aware Near-Optimal Scheduling for Heterogeneous Multi-Core Systems with Specialized Accelerators

TL;DR

This paper introduces a formal proof for the optimal scheduling policy in heterogeneous multi-core systems with specialized accelerators and priorities, along with a near-optimal algorithm that outperforms conventional policies.

Contribution

It provides the first formal proof of optimal scheduling in complex heterogeneous systems and proposes a fast near-optimal algorithm with a heuristic for priority-aware scheduling.

Findings

Algorithm is only 0.3% from optimal

Outperforms conventional scheduling policies

Effective in systems with multiple resource types

Abstract

To deliver high performance in power limited systems, architects have turned to using heterogeneous systems, either CPU+GPU or mixed CPU-hardware systems. However, in systems with different processor types and task affinities, scheduling tasks becomes more challenging than in homogeneous multi-core systems or systems without task affinities. The problem is even more complex when specialized accelerators and task priorities are included. In this paper, we provide a formal proof for the optimal scheduling policy for heterogeneous systems with arbitrary number of resource types, including specialized accelerators, independent of the task arrival rate, task size distribution, and resource processing order. We transform the optimal scheduling policy to a nonlinear integer optimization problem and propose a fast, near-optimal algorithm. An additional heuristic is proposed for the case of priority-aware scheduling. Our experimental results demonstrate that the proposed algorithm is only 0.3% from the optimal and superior to conventional scheduling policies.