Processor Abstraction in Computer System Models
Ilya Gluhovsky
Abstract
Performance models for computer systems are widely used to evaluate architectural tradeoffs early in the design cycle and to project the behavior of a given workload on a proposed architecture. Such models typically rely on a high-level abstraction of system components and the way they interact with a given workload. A simple example is a collection of cache miss rates used to (partially) describe the memory system. In this work we propose an abstraction of processor behavior. Our goal is to discern the main attributes of overlapping cache misses with each other and with other useful work. Our basic constructs are the probability distributions of the miss interarrival times and the times between the miss and the corresponding processor stall. It will be seen that the proposed abstraction results in errors of only up to 3 percent as compared with cycle accurate simulation. Furthermore, we will show that the constructs are latency invariant. This allows one to model a variety of system interconnects which typically have many different levels of latency.