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Title: X-SRQ - Improving Scalability and Performance of Multi-Core InfiniBand Clusters

Conference ·
OSTI ID:1016037

To improve the scalability of InfiniBand on large scale clusters Open MPI introduced a protocol known as B-SRQ [2]. This protocol was shown to provide much better memory utilization of send and receive buffers for a wide variety of benchmarks and real-world applications. Unfortunately B-SRQ increases the number of connections between communicating peers. While addressing one scalability problem of InfiniBand the protocol introduced another. To alleviate the connection scalability problem of the B-SRQ protocol a small enhancement to the reliable connection transport was requested which would allow multiple shared receive queues to be attached to a single reliable connection. This modified reliable connection transport is now known as the extended reliable connection transport. X-SRQ is a new transport protocol in Open MPI based on B-SRQwhich takes advantage of this improvement in connection scalability. This paper introduces the X-SRQ protocol and details the significantly improved scalability of the protocol over B-SRQand its reduction of the memory footprint of connection state by as much as 2 orders of magnitude on large scale multi-core systems. In addition to improving scalability, performance of latency-sensitive collective operations are improved by up to 38% while significantly decreasing the variability of results. A detailed analysis of the improved memory scalability as well as the improved performance are discussed.

Research Organization:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). National Center for Computational Sciences (NCCS)
Sponsoring Organization:
USDOE Office of Science (SC)
DOE Contract Number:
DE-AC05-00OR22725
OSTI ID:
1016037
Resource Relation:
Conference: 15th European Parallel-Virtual-Machine-and-Message-Passing-Interface-Users-Group Meeting (PVM/MPI), Dublin, Ireland, 20080907, 20080910
Country of Publication:
United States
Language:
English