MT~r 2 An Efficient Buffer Management Method for Cachet

We propose an efficient buffer management method for Cachet [7], called BCachet. Cachet is an adaptive cache coherence protocol based on a mechanism-oriented memory model called Commit-Reconcile & Fences (CRF) [1]. Although Cachet is theoretically proved to be sound and live, a direct implementation of Cachet is not feasible because it requires too expensive hardware. We greatly reduced the hardware cost for buffer management in BCachet without chang-ing the memory model and the adaptive nature of Cachet. Hardware cost for the incoming message buffer of the memory site is greatly reduced from PxN FIFOs to two FIFOs in BCachet where P is the number of sites and N is the number of address lines in a memory unit. We also reduced the minimum size of suspended message buffer per memory site from (log2 P+V) xPxrqma, to log2 P where V is the size of a memory block in terms of bits and rqma is the maximum number of request messages per cache. BCachet has three architectural merits. First, BCachet separates buffer management units for deadlock avoidance and those units for livelock avoidance so that a designer ha