Efficient Block Device Sharing over Myrinet with Memory Bypass

Efficient sharing of block devices over an interconnection network is an important step in deploying a shared-disk parallel file system on a cluster of SMPs. In this paper represent gmbock, a client/server system for network sharing of storage devices over Myrinet, which uses an optimized data path in order to transfer data directly from the storage medium to the NIC, bypassing the host CPU and main memory bus. Its design enhances existing programming abstractions, combining the user level networking characteristics of Myrinet with Linux´s virtual memory infrastructure, in order to construct the datapath in a way that is independent of the type of block device used. Experimental evaluation of a prototype system shows that remote I/O bandwidth can improve up to 36.5%, compared to an RDMA-based implementation. Moreover, interference on the main memory bus of the host is minimized, leading to an up to 41% improvement in the execution time of memory-intensive applications.