Abstract

Fine-grained concurrent object-oriented programming (COOP) models which provide a shared namespace, object-level concurrency and implicit dynamic thread creation can simplify the programming of irregular parallel applications on distributed memory machines. Unfortunately, COOP models are often perceived as inefficient and thus few complete applications have been implemented in COOP languages. In this paper, we study the implementation techniques required to obtain efficient parallel execution of fine-grained COOP languages using a complete, medium-sized protein molecular dynamics program, IC-CEDAR. We found that even given high data locality and achieving good sequential efficiency, an implementation that relies only on thread-oriented compiler and runtime optimizations and software multithreading fails to achieve parallel efficiency. We show that two major sources of overhead --- lack of processor-level data reuse and fine-grained threads for remote object accesses --- contribute to t...

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