Dynamic Access Ordering for Symmetric Multiprocessors

Author:McKee, Sally, Department of Computer ScienceUniversity of Virginia

Memory bandwidth is rapidly becoming the performance bottleneck in the application of high performance microprocessors to vector-like algorithms, including the "Grand Challenge" scien- tific 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 in symmetric multiprocessor (SMP) systems. Our technique combines compile-time detection of memory access patterns with a memory subsystem (called a Stream Memory Controller, or SMC) that decouples the order of requests generated by the computational elements 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. Our simulations indicate that SMP SMC systems can consistently deliver nearly the full system bandwidth.

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Source Citation:

McKee, Sally. "Dynamic Access Ordering for Symmetric Multiprocessors." University of Virginia Dept. of Computer Science Tech Report (1994).

University of Virginia, Department of Computer Science
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