Optimizing software data prefetches with rotating registers

Software data prefetching is a well-known technique to improve the performance of programs that suffer many cache misses at several levels of memory hierarchy. However, it has significant overhead in terms of increased code size, additional instructions, and possibly increased memory bus traffic due...

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Bibliographic Details
Published in:Proceedings 2001 International Conference on Parallel Architectures and Compilation Techniques 2001, p.257-267
Main Authors: Doshi, G., Krishnaiyer, R., Muthukumar, K.
Format: Article
Language:English
Subjects:
Availability
Computer architecture
Delay
Educational institutions
Optimization methods
Prefetching
Production
Registers
Scheduling
Software performance
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Summary:Software data prefetching is a well-known technique to improve the performance of programs that suffer many cache misses at several levels of memory hierarchy. However, it has significant overhead in terms of increased code size, additional instructions, and possibly increased memory bus traffic due to redundant prefetches. This paper presents two novel methods to reduce the overhead of software data prefetching and improve the program performance by optimized prefetch scheduling. These methods exploit the availability of rotating registers and predication in architectures such as the Itanium/sup TM/ architecture. The methods (I) minimize redundant prefetches, (2) reduce the number of issue slots needed for prefetch instructions, and (3) avoid branch mispredict penalties - all with minimal code size increase. Compared to traditional data prefetching techniques, these methods (i) do not require loop unrolling, (ii) do not require predicate computations and (iii) require fewer machine resources. One of these methods has been implemented in the Intel Production Compiler for the ItaniumTM processor. This technique is compared with traditional approaches for software prefetching and experimental results are presented based on the floating-point benchmark suite of CPU2000.
ISSN:1089-796X
DOI:10.1109/PACT.2001.953306