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2010 19th International Conference on Parallel Architectures and Compilation Techniques (PACT) (2010)
Vienna, Austria
Sept. 11, 2010 to Sept. 15, 2010
ISBN: 978-1-5090-5032-1
pp: 477-488
George Kurian , Massachusetts Institute of Technology, Cambridge, MA 02139, USA
Jason E. Miller , Massachusetts Institute of Technology, Cambridge, MA 02139, USA
James Psota , Massachusetts Institute of Technology, Cambridge, MA 02139, USA
Jonathan Eastep , Massachusetts Institute of Technology, Cambridge, MA 02139, USA
Jifeng Liu , Massachusetts Institute of Technology, Cambridge, MA 02139, USA
Jurgen Michel , Massachusetts Institute of Technology, Cambridge, MA 02139, USA
Lionel C. Kimerling , Massachusetts Institute of Technology, Cambridge, MA 02139, USA
Anant Agarwal , Massachusetts Institute of Technology, Cambridge, MA 02139, USA
ABSTRACT
Based on current trends, multicore processors will have 1000 cores or more within the next decade. However, their promise of increased performance will only be realized if their inherent scaling and programming challenges are overcome. Fortunately, recent advances in nanophotonic device manufacturing are making CMOS-integrated optics a reality—interconnect technology which can provide significantly more bandwidth at lower power than conventional electrical signaling. Optical interconnect has the potential to enable massive scaling and preserve familiar programming models in future multicore chips. This paper presents ATAC, a new multicore architecture with integrated optics, and ACKwise, a novel cache coherence protocol designed to leverage ATAC's strengths. ATAC uses nanophotonic technology to implement a fast, efficient global broadcast network which helps address a number of the challenges that future multicores will face. ACKwise is a new directory-based cache coherence protocol that uses this broadcast mechanism to provide high performance and scalability. Based on 64-core and 1024-core simulations with Splash2, Parsec, and synthetic benchmarks, we show that ATAC with ACKwise out-performs a chip with conventional interconnect and cache coherence protocols. On 1024-core evaluations, ACKwise protocol on ATAC outperforms the best conventional cache coherence protocol on an electrical mesh network by 2.5x with Splash2 benchmarks and by 61% with synthetic benchmarks.
INDEX TERMS
Cache Coherence, Network-on-Chip, Photonic Interconnect
CITATION
George Kurian, Jason E. Miller, James Psota, Jonathan Eastep, Jifeng Liu, Jurgen Michel, Lionel C. Kimerling, Anant Agarwal, "ATAC: A 1000-core cache-coherent processor with on-chip optical network", 2010 19th International Conference on Parallel Architectures and Compilation Techniques (PACT), vol. 00, no. , pp. 477-488, 2010, doi:
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