Efficient Zero-Copy Noncontiguous I/O for Globus on InfiniBand

Noncontiguous I/O access is one of the main access patterns in parallel and distributed applications. An I/O architecture EXIO enables Globus, a popular run-time environment for distributed computing, on RDMA networks such as InfiniBand. In this paper, we investigate the benefits of InfiniBand zero-copy RDMA to noncontiguous I/O on Globus. Our experimental results demonstrate that, by enabling zero-copy RDMA on InfiniBand, EXIO significantly improves the performance of Globus noncontiguous I/O. Compared to the packing and unpacking, zero-copy RDMA improve the bandwidth by up to 2.7 times. Compared to both IPoIB and 10GigE, it increases the bandwidth by more than three times. While achieving efficient noncontiguous I/O, RDMA-based noncontiguous I/O on InfiniBand also leads to dramatical reduction of CPU utilization on Globus clients and servers.