Title
Design and implementation of the blue gene/P snoop filter
Abstract
As multi-core processors evolve, coherence traffic between cores is becoming problematic, both in terms of performance and power. The negative effects of coherence (snoop) traffic can be significantly mitigated through snoop filtering. Shielding each cache with a device that can squash snoop requests for addresses known not to be in cache improves performance significantly for caches that cannot perform normal load and snoop lookups simultaneously. In addition, reducing snoop lookups yields power savings. This paper describes the design of the Blue Gene/P snoop filters, and presents hardware measurements to demonstrate their effectiveness. The Blue Gene/P snoop filters combine stream registers and snoop caches to capture both the locality of snoop addresses and their streaming behavior. Simulations of SPLASH-2 benchmarks illustrate tradeoffs and strengths of these two techniques. Their combination is shown to be most effective, eliminating 94-99% of all snoop requests using very few stream registers and snoop cache lines. This translates into an average performance improvement of almost 20% for the NAS benchmarks running on an actual Blue Gene/P system.
Year
DOI
Venue
2008
10.1109/HPCA.2008.4658623
Salt Lake City, UT
Keywords
Field
DocType
computer architecture,filters,mainframes,parallel machines,SPLASH-2 benchmarks,blue gene-P snoop filter,coherence traffic negative effects,multicore processors,snoop lookups
Locality,System on a chip,Cache,Computer science,Parallel computing,Blue gene,Filter (signal processing),Real-time computing,Filtering theory,Multi-core processor,Performance improvement
Conference
ISSN
ISBN
Citations 
1530-0897
978-1-4244-2070-4
21
PageRank 
References 
Authors
1.00
15
3
Name
Order
Citations
PageRank
Valentina Salapura1211.00
Matthias A. Blumrich2211.00
Alan Gara3211.00