Improving Prediction for Procedure Returns with Return-address-stack Repair Mechanisms

This paper evaluates several mechanisms for repairing the return-address stack after branch mispredictions. The return-address stack is a small but important structure for achieving better control-flow prediction accuracy and therefore better performance. But wrong-path execution after mispredictions frequently corrupts the return-address stack, making repair mechanisms necessary. If the processor implements multipath execution--simultaneously executing both sides of a branch--the contention among different paths makes the problem more severe. For conventional, single-path processors, this paper proposes saving both the top-of-stack pointer and the top-ofstack contents for later restoration in case of a misprediction. This simple technique achieves nearly 100% hit rates and improves performance by up to 8.7% compared to a stack with no repair mechanism. For multipath processors, providing each path with its own return-address stack completely eliminates contention, improving performan...

• Type: Conference
• Year: 1998
• Where: MICRO
• Authors: Kevin Skadron, Pritpal S. Ahuja, Margaret Martonosi, Douglas W. Clark
• Keywords: Better Control-flow Prediction, Hardware, MICRO 1998, Repair Mechanism, Return-address Stack