Enhancing memory level parallelism via recovery-free value prediction

H Zhou, TM Conte�- Proceedings of the 17th annual International�…, 2003 - dl.acm.org
Proceedings of the 17th annual International Conference on Supercomputing, 2003dl.acm.org
The ever-increasing computational power of contemporary microprocessors reduces the
execution time spent on arithmetic computations (ie, the computations not involving slow
memory operations such as cache misses) significantly. Therefore, for memory intensive
workloads, it becomes more important to overlap multiple cache misses than to overlap slow
memory operations with other computations. In this paper, we propose a novel technique to
parallelize sequential cache misses, thereby increasing memory-level parallelism (MLP)�…
The ever-increasing computational power of contemporary microprocessors reduces the execution time spent on arithmetic computations (i.e., the computations not involving slow memory operations such as cache misses) significantly. Therefore, for memory intensive workloads, it becomes more important to overlap multiple cache misses than to overlap slow memory operations with other computations. In this paper, we propose a novel technique to parallelize sequential cache misses, thereby increasing memory-level parallelism (MLP). Our idea is based on the value prediction, which was proposed originally as an instruction-level-parallelism (ILP) optimization to break true data dependencies. In this paper, we advocate value prediction in its capability to enhance MLP instead of ILP. We propose to use value prediction and value speculative execution only for prefetching so that the complex prediction validation and misprediction recovery mechanisms are avoided and only minor changes in the microarchitecture are needed. The same hardware modifications also enable aggressive memory disambiguation for prefetching. The experimental results show that our technique enhances MLP effectively and achieves significant speedups even with a simple stride value predictor.
ACM Digital Library