Execution-driven simulation of a superscalar processor

Describes an accurate and efficient simulator for a superscalar processor, the IBM RISC System/6000. This simulator was developed to obtain timing estimates for the execution of programs in an execution-driven simulation system. The simulator uses a new technique called in situ profiling, and a simplified runtime model of the RS/6000 processor to obtain dynamic timing estimates. The runtime model simulates the functional units of the processor as well as the data cache. It incorporates a novel approach to simulate the synchronization of the fixed-point and floating-point units which allows accurate timing predictions at relatively low cost. The time estimates produced by the profiler are typically within 5% of the measured times for a variety of programs.<>