Speaker: Sandhya Dwarkadas, University of Rochester
Date: January 29, 1998
Transparent Shared Memory on Clusters of SMPs Using Remote-Write Networks
I will describe a "two-level" software distributed shared memory system (DSM) --- Cashmere-2L --- that meets this challenge. Cashmere-2L uses hardware to share memory within an SMP, and carefully reduces interference with normal execution due to software coherence maintenance across SMPs, by allowing a high level of asynchrony in the protocol.
Low-latency high-bandwidth remote-write networks, such as DEC's Memory Channel, provide the possibility of transparent, inexpensive access to the memory on remote SMPs. These networks suggest the need to re-evaluate the assumptions underlying the design of DSM protocols, and specifically, to consider protocols that communicate consistency information at a much finer grain. I will discuss the design trade-offs in the context of Cashmere-2L. Experimental results to evaluate the effects on performance of our design decisions will be presented.