Name
Abstract | ||
|---|---|---|
As the core counts increase in each chip multiprocessor generation, coherence protocols should improve scalability inperformance, area, and energy consumption to meet the demandsof larger core counts. Directory-based protocols constitute themost scalable alternative. A conventional directory, however, suffers from an inefficient use of storage and energy. First, thelarge, non-scalable, sharer vectors consume unnecessary area andleakage, especially considering that most of the blocks trackedin a directory are cached by a single core. Second, althoughincreasing directory size and associativity could boost systemperformance, it would come at expenses of energy consumption. This paper proposes the Dynamic Way Partitioning (DWP) Directory, a directory structure that exploits three main workloadcharacteristics to achieve area and energy reductions. First, it iswidely known that even in parallel workloads most of the accessedcache blocks are private. Second, most directory accesses targetthe small number of shared blocks. Third, the shared/privateratio of entries in the directory varies across applications andacross different execution phases within the applications. To takeadvantage of these three characteristics, DWP-Directory reducesthe number of ways with storage for shared blocks and it allowsthis storage to be powered off or on at run-time according to thedynamic requirements of the applications. DWP-Directory is compared to a conventional directory cachewith different associativity degrees and with two state-of-the-artschemes: PS-Directory and Hybrid Representation. Experimentalresults for 32-core CMPs show that DWP-Directory achievesthe best of both worlds: similar performance as a traditionaldirectory with high associativity, and similar area as recentstate-of-the-art schemes. In addition, DWP-Directory reducesstatic and dynamic power consumption by 38.0% and 67.4%,respectively compared to conventional sparse directories. |
Year | DOI | Venue |
|---|---|---|
2016 | 10.1109/HiPC.2016.051 | 2016 IEEE 23rd International Conference on High Performance Computing (HiPC) |
Keywords | Field | DocType |
directory cache,dynamic private-shared partitioning,coherence protocols,scalability,directory-based protocols,sharer vectors,system performance,energy consumption,dynamic way partitioning directory,DWP directory,energy reductions,PS-directory,hybrid representation,static power consumption reduction,dynamic power consumption reduction | Single-core,Computer science,Directory,Cache,Parallel computing,Multiprocessing,Dynamic demand,Energy consumption,Scalability,Distributed computing,Directory structure | Conference |
ISSN | ISBN | Citations |
1094-7256 | 978-1-5090-5412-1 | 0 |
PageRank | References | Authors |
0.34 | 20 | 4 |
Name | Order | Citations | PageRank |
|---|---|---|---|
| Joan J. Valls | 1 | 9 | 1.83 |
| María Engracia Gómez | 2 | 149 | 17.48 |
| Alberto Ros | 3 | 384 | 32.60 |
| Julio Sahuquillo | 4 | 420 | 53.71 |