Polling watchdog: combining polling and interrupts for efficient message handling

  • Authors:

  • Olivier Maquelin;Guang R. Gao;Herbert H. J. Hum;Kevin B. Theobald;Xin-Min Tian

  • Affiliations:

  • School of Computer Science, McGill University, 3480 University St., Montréal, Canada, H3A 2A7;School of Computer Science, McGill University, 3480 University St., Montréal, Canada, H3A 2A7;Dept. of Elec. and Comp. Eng., Concordia University, 1455 de Maisonneuve W., Montréal, Canada, H3G 1M8;School of Computer Science, McGill University, 3480 University St., Montréal, Canada, H3A 2A7;School of Computer Science, McGill University, 3480 University St., Montréal, Canada, H3A 2A7

  • Venue:
  • ISCA '96 Proceedings of the 23rd annual international symposium on Computer architecture
  • Year:
  • 1996

Quantified Score

Hi-index 0.00

Visualization

Abstract

Parallel systems supporting multithreading, or message passing in general, have typically used either polling or interrupts to handle incoming messages. Neither approach is ideal; either may lead to excessive overheads or message-handling latencies, depending on the application. This paper investigates a combined approach---Polling Watchdog, where both are used depending on the circumstances. The Polling Watchdog is a simple hardware extension that limits the generation of interrupts to the cases where explicit polling fails to handle the message quickly. As an added benefit, this mechanism also has the potential to simplify the interaction between interrupts and the network accesses performed by the program.We present the resulting performance for the EARTH-MANNA-S system, an implementation of the EARTH (Efficient Architecture for Running THreads) execution model on the MANNA multiprocessor. In contrast to the original EARTH-MANNA system, this system does not use a dedicated communication processor. Rather, synchronization and communication tasks are performed on the same processor as the regular computations. Therefore, an efficient message-handling mechanism is essential to good performance. Simulation results and performance measurements show that the Polling Watchdog indeed performs better than either polling or interrupts alone. In fact, this mechanism allows the EARTH-MANNA-S system to achieve the same level of performance as the original EARTH-MANNA multithreaded system.