Kim et al. use the page table to record the potential sharers of each memory page. Snoops are then send only to those nodes. The motivation is similar to the Page Sharing Table work of Ekman et al. In the base design, shares per page are added once the node accesses any block within the page. Since the sharing information is in the page table, a node knows when it accesses a page for the first time and can add itself in the corresponding sharing vector. A sharing node is never removed in the base design. Over time, the sharing vectors can become overpopulated and unrepresentative of the current sharing status. Accordingly, a page sharing shrinking method is proposed based on counting-bloom filters similar to those used in RegionScout.

Kim, D., Ahn, J., Kim, J., and Huh, J. 2010. Subspace snooping: filtering snoops with operating system support. In Proceedings of the 19th international Conference on Parallel Architectures and Compilation Techniques (Vienna, Austria, September 11 - 15, 2010). PACT '10. ACM, New York, NY, 111-122. DOI= http://doi.acm.org/10.1145/1854273.1854292