Architectural Considerations for Application-Specific Counterflow PipelinesReport
Application-specific processor design is a promising approach for meeting the perfor- mance and cost goals of a system. Application-specific processors are especially prom- issuing for embedded systems (e.g., digital cameras, cellular phones, etc.) where a small increase in performance and decrease in cost can have a large impact on a product's viability. Sutherland, Sproull, and Molnar have proposed a new pipeline organization called the Counterflow Pipeline (CFP). This paper evaluates CFP design alternatives and shows that the CFP is an ideal architecture for fast, low-cost design of high-perfor- mance processors customized for computation-intensive embedded applications. First, we describe why CFP's are particularly well-suited to realizing application-specific pro- cessors. Second, we describe how a CFP tailored to an application can be constructed automatically. Third, we present measurements that evaluate CFP design trade-offs and show that CFP's provide speculative and out-of-order execution, and register renaming that is matched to an application. Fourth, we show that asynchronous counterflow pipe- lines achieve high-performance by reducing the average execution latency of instruc- tins over synchronous implementations. Finally, we demonstrate that custom CFP's achieve cycles per instruction measurements that are competitive with 4-way supersca- lar out-of-order processors at a potentially low design complexity.
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Bruce, R, and W Jack. "Architectural Considerations for Application-Specific Counterflow Pipelines." University of Virginia Dept. of Computer Science Tech Report (1998).
University of Virginia, Department of Computer Science