Two-level coherence predictors have shown great promise to reduce coherence overhead in shared memory multiprocessors. However, to be accurate they require a memory overhead that on e.g. a 64-processor machine can be as high as 50%.

Based on an application case study consisting of seven applications from SPLASH-2, a first observation made in this paper is that memory blocks subject to coherence activities usually constitute only a small fraction (around 10%) of the entire application footprint. Based on this, we contribute with a new class of resource-efficient coherence predictors that is organized as a cache attached to each memory controller. We show that such a Coherence Predictor Cache (CPC) can provide nearly as effective predictions as if a predictor is associated with every memory block, but needs only 2-7% as many predictors.