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Low-latency remote-write networks, such as DEC’s Memory Channel, provide the possibility of transparent, inexpensive, huge-scale shared-memory parallel computing on clusters of shared memory multiprocessors (SMPs). The challenge is to take advantage of hardwaresharedmemoryfor sharing within an SMI: and to ensure that software overheadis incurredonly when actively sharing data across SMPs in the cluster. In this paper, we describe a ‘Ywolevel” software coherent shared memory system-Cashmere-2L-that meets this challenge. CashmereSL uses hardware to share memory within a node, while exploiting the Memory Channel’s remote-write capabilities to implement “moderately lazy” release consistency with multiple concurrent writers, directories, home nodes, and page-size coherence blocks across nodes. Cashmere-2L employs a novel coherence protocol that allows a high level of asynchrony by …