A comprehensive bibliography of distributed shared memory
ACM SIGOPS Operating Systems Review
Boosting the performance of hybrid snooping cache protocols
ISCA '95 Proceedings of the 22nd annual international symposium on Computer architecture
A cost-comparison approach for adaptive distributed shared memory
ICS '96 Proceedings of the 10th international conference on Supercomputing
Analytical Prediction of Performance for Cache Coherence Protocols
IEEE Transactions on Computers
IEEE Transactions on Parallel and Distributed Systems
Two Adaptive Hybrid Cache Coherency Protocols
HPCA '96 Proceedings of the 2nd IEEE Symposium on High-Performance Computer Architecture
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Since data access patterns vary from application to application, neither write-invalidate nor write-update is the better strategy for maintaining cache coherence in all cases. Thus, it may be advantageous to use a hybrid cache coherency protocol that combines the best aspects of each. Although write-invalidate is the dominant approach in commercial multiprocessors, the recent introduction of coalescing write buffers combined with relaxed models of memory consistency can be expected to improve the performance of protocols based on updating. This motivates our re-examination of the relative performance of write-invalidate, write-update, and on-line dynamic hybrid protocols. Using a detailed program-driven simulation of a high-performance bus-based multiprocessor with release-consistent caching, we compare the performance of several variations on the hybrid protocol used in DEC AXP multiprocessors with the performance of several more conventional protocols. The variations on the hybrid protocol are introduced to correct weaknesses that appeared during the study. Though coalescing write buffers offer large performance improvements to the protocols that use update, conventional write-invalidate protocols also benefit. It appears that, although hybrid protocols do not offer any significant advantage over the best choice of pure protocol for a particular program, they may offer good performance over a wider range of applications than any single pure protocol.