Exploiting atomic operations for barrier on cray XE/XK systems

  • Authors:

  • Manjunath Gorentla Venkata;Richard L. Graham;Joshua S. Ladd;Pavel Shamis;Nathan T. Hjelm;Samuel K. Gutierrez

  • Affiliations:

  • Oak Ridge National Laboratory, Oak Ridge, TN;Oak Ridge National Laboratory, Oak Ridge, TN;Oak Ridge National Laboratory, Oak Ridge, TN;Oak Ridge National Laboratory, Oak Ridge, TN;Los Alamos National Laboratory, Los Alamos, NM;Los Alamos National Laboratory, Los Alamos, NM

  • Venue:
  • EuroMPI'12 Proceedings of the 19th European conference on Recent Advances in the Message Passing Interface
  • Year:
  • 2012

Quantified Score

Hi-index 0.00

Visualization

Abstract

Barrier is a collective operation used by many scientific applications and parallel libraries for synchronization. Typically, a Barrier operation is implemented by exchanging a short data message that requires demultiplexing, thereby adding undesired latency to the operation. In this work, we reduce the latency of Barrier operations for Cray XE/XK systems by leveraging the atomic operations provided by the Gemini interconnect, tailoring algorithms to utilize these capabilities, and utilizing a hierarchical design to arrive at an efficient implementation. Our micro-benchmark evaluation shows that for a 4,096 process Barrier operation, the atomic-operations-based Barrier outperforms the data exchange Barrier by 52% and the native Barrier by 111%.