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MICRO
2009
IEEE

A tagless coherence directory

14 years 5 months ago
A tagless coherence directory
A key challenge in architecting a CMP with many cores is maintaining cache coherence in an efficient manner. Directory-based protocols avoid the bandwidth overhead of snoop-based protocols, and therefore scale to a large number of cores. Unfortunately, conventional directory structures incur significant area overheads in larger CMPs. The Tagless Coherence Directory (TL) is a scalable coherence solution that uses an implicit, conservative representation of sharing information. Conceptually, TL consists of a grid of small Bloom filters. The grid has one column per core and one row per cache set. TL uses 48% less area, 57% less leakage power, and 44% less dynamic energy than a conventional coherence directory for a 16-core CMP with 1MB private L2 caches. Simulations of commercial and scientific workloads indicate that TL has no statistically significant impact on performance, and incurs only a 2.5% increase in bandwidth utilization. Analytical modelling predicts that TL continues to ...
Jason Zebchuk, Vijayalakshmi Srinivasan, Moinuddin
Added 24 May 2010
Updated 24 May 2010
Type Conference
Year 2009
Where MICRO
Authors Jason Zebchuk, Vijayalakshmi Srinivasan, Moinuddin K. Qureshi, Andreas Moshovos
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