Duetto: Latency Guarantees at Minimal Performance Cost

Abstract

The management of shared hardware resources in multi-core platforms has been characterized by a fundamental trade-off: high-performance arbiters typically employed in COTS systems offer no worst-case guarantees, while dedicated real-time controllers provide timing guarantees at the cost of significantly degrading system performance. In this paper, we overcome this trade-off by introducing Duetto, a novel hardware resource management paradigm. Duetto pairs a real-time arbiter with a high-performance arbiter and a latency estimator module. Based on the observation that the resource is rarely overloaded, Duetto executes the high-performance arbiter most of the time, switching to the real-time arbiter only in the rare cases when the latency estimator deems that timing guarantees risk being violated. We demonstrate our approach on the case study of a multi-bank memory. Our evaluation based on cycle-accurate simulations shows that Duetto can provide the same latency guarantees as the real-time arbiter with limited loss of performance compared to the high-performance arbiter.