Remote Control: A Simple Deadlock Avoidance Scheme for Modular Systems-on-Chip

Abstract

Ever increasing performance demand and shrinking in the transistor size together result in complex and dense packing in large chips. That motivates designers to opt for many small specialized hardware modules in a chip to extract maximum performance benefits with relatively lower complexity and cost. These altogether opens up new directions for heterogeneous modular System-on-Chip (SoC) research, where a large system is built by assembling small independently designed chiplets (small chips). We focus on the communication aspect of such SoCs, especially the newly observed deadlock among chiplets. Even though deadlock is a classic problem in networks and many solutions are available, the modular SoC design demands customized solutions that preserves the design flexibility for chiplet designers. We propose <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Remote Control (RC)</i> , a simple routing oblivious deadlock avoidance scheme based on selective injection-control mechanism. Along with guarantee on deadlock freedom, <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">RC</i> aims to provide a methodology to make each independently designed chiplet seamlessly integrate in any modular SoCs. We achieve up to 56.34% throughput and 15.49% zero load latency improvements on synthetic traffic and up to 20% speedup on real workloads taken from vast range of benchmark suites, over the state-of-the-art turn restriction based technique applied in the modular SoC domain.