1 / 12

Scalable Directory Protocols for 1000s of Cores

Scalable Directory Protocols for 1000s of Cores. Dominic DiTomaso EE 6633. Outline. Introduction Background ATAC SPATL Cuckoo Directory SCD Conclusions. Directory Protocols. Snoopy (broadcast) -> Directory (multicast) Large Directory Overhead Overhead = P*M P - # of processors

gabi
Download Presentation

Scalable Directory Protocols for 1000s of Cores

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Scalable Directory Protocols for 1000s of Cores Dominic DiTomaso EE 6633

  2. Outline • Introduction • Background • ATAC • SPATL • Cuckoo Directory • SCD • Conclusions

  3. Directory Protocols • Snoopy (broadcast) -> Directory (multicast) • Large Directory Overhead • Overhead = P*M • P - # of processors • M - # of memory blocks • 64 nodes: 12.7% overhead • 256 nodes: 50% overhead • 1024 nodes: 200% overhead P M

  4. Directory Protocols • Requirements • Small area, energy, and latency overheads • Accurate sharer information • Limited directory-induced invalidations • Duplicate Tags • Area-efficient • High associativity -> high power • Sparse Directory • Power-efficient • Large capacity -> large area • Coarse-grain vectors, Hierarchical, etc.

  5. ATAC • Optical Broadcast Network

  6. SPATL • Tagless • Bloom Filters

  7. Cuckoo Directory • N-ary Cuckoo Hash Table

  8. SCD • Variable directory tags

  9. SCD (cont.)

  10. SCD (cont.)

  11. Conclusions • Large directory overhead at 1000s of cores • Solutions • Optics – ATAC • Tagless – SPATL • Hash Tables – Cuckoo • Variable Tags – SCD

  12. References • [1] George Kurian, Jason E. Miller, James Psota, Jonathan Eastep, Jifeng Liu, Jurgen Michel, Lionel C. Kimerling, and AnantAgarwal, “ATAC: a 1000-core cache-coherent processor with on-chip optical network,” In Proceedings of the 19th international conference on Parallel architectures and compilation techniques (PACT '10), 2010. • [2] Daniel Sanchez and Christos Kozyrakis, “SCD: A scalable coherence directory with flexible sharer set encoding,” In Proceedings of the 2012 IEEE 18th International Symposium on High-Performance Computer Architecture (HPCA '12), 2012. • [3] H. Zhao, A. Shriraman, S. Dwarkadas, and V. Srinivasan, “SPATL: Honey, I Shrunk the Coherence Directory,” In Proceedings of the 20th international conference on Parallel architectures and compilation techniques (PACT ’11), 2011. • [4] M. Ferdman, P. Lotfi-Kamran, K. Balet, B. Falsafi, "Cuckoo directory: A scalable directory for many-core systems," 2011 IEEE 17th International Symposium onHigh Performance Computer Architecture (HPCA), pp.169-180, Feb. 2011.

More Related