A unified model for multicore architectures

Abstract

With the advent of multicore and many core architectures, we are facing a problem that is new to parallel computing, namely, the management of hierarchical parallel caches. One major limitation of all earlier models is their inability to model multicore processors with varying degrees of sharing of caches at different levels. We propose a unified memory hierarchy model that addresses these limitations and is an extension of the MHG model developed for a single processor with multi-memory hierarchy. We demonstrate that our unified framework can be applied to a number of multicore architectures for a variety of applications. In particular, we derive lower bounds on memory traffic between different levels in the hierarchy for financial and scientific computations. We also give a multicore algorithms for a financial application that exhibits a constant-factor optimal amount of memory traffic between different cache levels. We implemented the algorithm on a multicore system with two Quad-Core Intel Xeon 5310 1.6GHz processors having a total of 8 cores. Our algorithms outperform compiler optimized and auto-parallelized code by a factor of up to 7.3.