REEL: Reducing effective execution latency of floating point operations

Vignyan Reddy, Syed Zohaib Gilani, Erika Gunadi, Nam Sung Kim, Michael J. Schulte, Mikko H. Lipasti

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The height of the dynamic dependence graph of a program, as executed by a processor, determines the minimum bound on the execution time. This height can be decreased by reducing the effective execution latency of operations that form dependence chains in the graph. In this paper, we propose a technique called REEL to reduce overall latency of chains of dependent floating point (FP) operations by increasing the throughput of computation. REEL comprises of a high-throughput floating point unit (HFP) that allows early issue of an FP Add that is dependent on another FP Add or FP Multiply. This is complemented by instruction scheduler modifications that allow early issue of dependent FP Adds, and a novel checker logic that corrects any precision errors. Unlike conventional static operation fusion, like fused Multiply-Add (FMA), there are no changes to the instruction set to enable utilization of the new hardware, and no recompilation is necessary. Furthermore, unlike ISA-level FMA, our technique produces results that are bit compatible while boosting performance of Add-Add dependence pairs in addition to Multiply-Add pairs. Our evaluation of REEL using CFP2006 benchmarks shows an average performance gain of 7.6% and maximum performance gain of 17% while consuming 1.2% lower energy.

Original languageEnglish (US)
Title of host publicationProceedings of the International Symposium on Low Power Electronics and Design, ISLPED 2013
Pages187-192
Number of pages6
DOIs
StatePublished - 2013
Externally publishedYes
Event2013 ACM/IEEE International Symposium on Low Power Electronics and Design, ISLPED 2013 - Beijing, China
Duration: Sep 4 2013Sep 6 2013

Publication series

NameProceedings of the International Symposium on Low Power Electronics and Design
ISSN (Print)1533-4678

Other

Other2013 ACM/IEEE International Symposium on Low Power Electronics and Design, ISLPED 2013
Country/TerritoryChina
CityBeijing
Period9/4/139/6/13

ASJC Scopus subject areas

  • Engineering(all)

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