Mower: A new design for non-blocking misprediction recovery

Mower is a micro-architecture technique which targets the branch misprediction penalty in superscalar processors. It speeds-up the misprediction recovery process by dynamically evicting stale instructions and correcting the Register Alias Table (RAT) using explicit control dependency tracking. Tracking control dependencies is accomplished by using simple bit matrices. This low-overhead technique allows overlapping of the recovery process with instruction fetching, renaming and scheduling from the correct path. Our evaluation of the mechanism indicates that it yields performance very close to ideal recovery and provides up to 5% speed-up and 2% reduction in power consumption compared to a recovery mechanism using a reorder buffer and a walker. The simplicity of the mechanism should permit easy implementation of Mower in an actual processor