Fast, Accurate Design Space Exploration of Embedded Systems Memory Configurations

Abstract

The memory hierarchy is often a critical component of an embedded system. An embedded system’s memory hierarchy can have dramatic impact on the overall cost, performance, and power consumption of the system. Consequently, designers spend considerable time evaluating potential memory system designs. Unfortunately, the range of options in the memory hierarchy (e.g., number, size, and type of caches, on-chip SRAM, DRAM, EPROM, etc.) makes thorough exploration of the design space using typical simulation techniques infeasible. This paper describes a fast, accurate technique to estimate an application’s average memory latency on a set of memory hierarchies. The technique is fast—two orders of magnitude faster than a full simulation. It is also accurate—extensive measurements show that 70 % of the estimates were within 1 percentage point of the actual cycle count while over 99 % of all estimates were within 10 percentage points of the actual cycle count. This fast, accurate technique provides the embedded system designer the ability to more fully explore the design space of potential memory hierarchies and select the one that best meets the system’s design requirements