Predictable dynamic instruction scratchpad for simultaneous multithreaded processors

Abstract

For precise timing analysis of hard-real applications a predictable memory system is of particular importance. Caches have a great impact on performance, but at the cost of reduced timing predictability. Conventional scratchpads, i.e. statically managed on-chip memories, provide predictable memory accesses, but they are usually badly utilized. Better memory utilization is allowed by dynamically managed scratchpads that are designed for predictability. In this paper we propose a function scratchpad that is dynamically managed in hardware and provides a predictable timing behavior. The function scratchpad exploits a simultaneous multithreaded architecture to increase the pipeline and memory bandwidth utilization while preserving predictability.