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Abstract : |
Memory bandwidth is rapidly becoming the performance bottleneck in the application of high performance microprocessors to vector-like algorithms, including the "grand challenge " scientific problems. Caching is not the sole solution for these applications due to the poor temporal and spatial locality of their data accesses. Moreover, the nature of memories themselves has changed. Achieving greater bandwidth requires exploiting the characteristics of memory components "on the other side of the cache "--- they should not be treated as uniform access-time RAM. This paper describes the use of hardware-assisted access ordering on a uniprocessor system. Our technique combines compile-time detection of memory access patterns with a memory subsystem that decouples the order of requests generated by the processor from that issued to the memory system. This decoupling permits the requests to be issued in an order that optimizes use of the memory system. We present numerous simulation results showing significant speedup on important scientific kernels., |
