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Conflict-Free Access for Streams in Multimodule Memories
May 1995 (vol. 44 no. 5)
pp. 634-646

Abstract—Address transformation schemes, such as skewing and linear transformations, have been proposed to achieve conflict-free access for streams with constant stride. However, this is achieved only for some strides. In this paper, we extend these schemes to achieve this conflict-free access for a larger number of strides. The basic idea is to perform an out-of-order access to a stream of fixed length. This stream is then stored in a local memory and used in subsequent instructions. This mode of operation is suitable for vector processors and for processors with decoupled access. The scheme and mode of operation proposed produce the largest possible number of conflict-free strides. Memory systems with any ratio between the number of memory modules and memory latency are considered. The hardware for address calculations and access control is described and shown to be of similar complexity as that required for access in order.

[1] P. Budnik and D.J. Kuck,“The organization and use of parallel memories,” IEEE Trans. Computers, vol. 20, no. 12, pp. 1,566-1,569, 1971.
[2] C-L. Chen and C-K Liao,“Analysis of vector access performance on skewedinterleaved memory,” Int’l Symp. Computer Architecture, pp. 387-394, 1989.
[3] J. Frailong,W. Jalby,, and J. Lenfant,“XOR-schemes: A flexible dataorganization in parallel memories,” Int’l Conf. Parallel Processing, pp. 276-283, 1985.
[4] J. Fu and J.H. Patel, "Data Prefetching in Multiprocessor Vector Cache Memories," Proc. 18th Int'l Symp. Computer Architecture, pp. 54-63, 1991.
[5] D.T. Harper III and J.R. Jump,“Performance evaluation of vector accesses inparallel memories using a skewed storage scheme,” Int’l Symp. Computer Architecture, pp. 324-328, 1986.
[6] D.T. Harper III,“Block, multistride vector and FFT accesses in parallel memorysystems,” IEEE Trans. Parallel and Distributed Systems, vol. 2, no. 1, pp. 43-51, 1991.
[7] D.T. Harper III and Y. Costa,“Analytical estimation of vector accessperformance in parallel memory architectures,” Internal Report, Dept. of Electrical Eng., Univ. of Texas at Dallas, 1991.
[8] D.T. Harper III and D.A. Linebarger,“Conflict-free vector access using adynamic storage scheme,” IEEE Trans. Computers, vol. 40, no. 3, pp. 276-283, 1991.
[9] D.H. Lawrie,“Access and alignment of data in an array processor,” IEEE Trans. Computers, vol. 24, no. 12, pp. 1,145-1,155, Dec. 1975.
[10] A. Norton and E. Melton,“A class of boolean linear transformations forconflict-free power-of-two stride access,” Int’l Conf. Parallel Processing, pp. 247-254, 1987.
[11] W. Oed and O. Lange,“On the effective bandwidth of interleaved memories invector processing systems,” IEEE Trans. Computers, vol. 34, no. 10, pp. 949-957, Oct. 1985.
[12] B.R. Rau,M.S. Schlansker,, and D.W.L. Yen,“The CydraTM5 stride-insensitivememory system,” Int’l Conf. Parallel Processing, pp. 242-246, 1989.
[13] B.R. Rau,“Pseudo-randomly interleaved memory,” Int’l Symp. Computer Architecture, pp. 74-83, 1991.
[14] M. Valero,T. Lang,, and E. Ayguadé,“Conflict-free access of vectors withpower-of-two strides,” Int’l Conf. Supercomputing, pp. 149-156, 1992.
[15] M. Valero,T. Lang,J.M. Llaberia,M. Peiron,E. Ayguadé,, and J.J. Navarro:, “Increasing the number of strides for conflict-free vector access,” Int’l Symp. Computer Architecture, pp. 372-381, 1992.
[16] S. Weiss,“An aperiodic storage scheme to reduce memory conflicts in vectorprocessors,” Int’l Symp. Computer Architecture, pp. 380- 386, 1989.
[17] H.A.G. Wijshoff and J. van Leeuwen,“The structure of periodic storage schemes forparallel memories,” IEEE Trans. Computers, vol. 34, pp. 501-505, June 1985.

Index Terms:
Conflict-free access, decoupled access, multimodule memories, out-of-order access, storage schemes, streams with constant strides, vector processors.
Citation:
Tomás Lang, Mateo Valero, Montse Peiron, Eduard Ayguadé, "Conflict-Free Access for Streams in Multimodule Memories," IEEE Transactions on Computers, vol. 44, no. 5, pp. 634-646, May 1995, doi:10.1109/12.381949
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