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Department of Computer Science,
University of Edinburgh,
The King's Buildings, Mayfield Road, Edinburgh EH9 3JZ,
Scotland, UK. The Advanced Computer Research Institute,
1, Boulevard Marius Vivier-Merle, 69443 Lyon,
France. Department of Mathematical and Computational Sciences,
University of St. Andrews,
The North Haugh, St. Andrews, Fife KY16 9SS,
Scotland, UK.

Performance of the Decoupled ACRI-1 Architecture: the Perfect Club

Nigel Topham1 and Kenneth McDougall23


This paper examines the performance potential of decoupled computer architectures on real-world codes, and includes the first performance bounds calculations to be published for the highly-decoupled ACRI-1 computer architecture. It also constitutes the first published work to report on the effectiveness of a decoupling Fortran90 compiler.

Decoupling is an architectural optimisation which offers very high sustained performance through large-scale latency hiding. This paper investigates the applicability of access and control decoupling to real-world codes. We illustrate this with compiler-generated decoupling optimisations for the Perfect Club benchmark suite on the Advanced Computer Research Institute's ACRI-1 system, utilising the frequency of loss of decoupling (LOD) events as a measure of the effectiveness of decoupling to each code. We derive bounds for the performance of these codes and show that, whilst some exhibit performance roughly equivalent to that on vector computers, others exhibit considerably higher performance potential in a decoupled system.
Wed Mar 1 16:43:22 GMT 1995