Kaxiras@cs.wisc.edu

In this paper we propose Instruction-based Prediction as a means to optimize directory-based cache coherent NUMA shared-memory. Instruction-based prediction is based on observing the behavior of load and store instructions in relation to coherent events and predicting their future behavior. Although this technique is well established in the uniprocessor world it has not been widely applied for optimizing transparent shared-memory where prediction ---in the form of adaptive cache coherence protocols--- is typically address-based. The advantage of this technique is that it requires very few hardware resources in the form of very small prediction tables per node. In contrast, address-based prediction typically requires storage proportional to the memory and/or cache size. To show the potential of instruction-based prediction we propose and evaluate four different optimizations: i) a migratory sharing optimization, ii) a wide sharing optimization iii) a pairwise sharing optimization, and i..