A comparison of entry consistency and lazy release consistency implementations

This paper compares several implementations of entry consistency (EC) and lazy release consistency (LRC), two relaxed memory models in use with software distributed shared memory (DSM) systems. We use six applications in our study: SOR, Quicksort, Water, Barnes-Hut, IS, and 3D-FFT. For these applications, EC's requirement that all shared data be associated with a synchronization object leads to a fair amount of additional programming effort. We identify, in particular, extra synchronization, lock rebinding, and object granularity as sources of extra complexity. In terms of performance, for the set of applications and for the computing environment utilized neither model is consistently better than the other. For SOR and IS, execution times are about the same, but LRC is faster for Water (33%) and Barnes-Hut (41%) and EC is faster for Quicksort (14%) and 3D-FFT (10%).