Accelerating Messages by Avoiding Copies in an Asynchronous Task-based Programming Model

Nitin Bhat, Sam White, Evan Ramos, Laxmikant V. Kale

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Task-based programming models promise improved communication performance for irregular, fine-grained, and load imbalanced applications. They do so by relaxing some of the messaging semantics of stricter models and taking advantage of those at the lower-levels of the software stack. For example, while MPI's two-sided communication model guarantees in-order delivery, requires matching sends to receives, and has the user schedule communication, task-based models generally favor the runtime system scheduling all execution based on the dependencies and message deliveries as they happen. The messaging semantics are critical to enabling high performance.In this paper, we build on previous work that added zero copy semantics to Converse/LRTS. We examine the messaging semantics of Charm++ as it relates to large message buffers, identify shortcomings, and define new communication APIs to address them. Our work enables in-place communication semantics in the context of point-to-point messaging, broadcasts, transmission of read-only variables at program startup, and for migration of chares. We showcase the performance of our new communication APIs using benchmarks for Charm++ and Adaptive MPI, which result in nearly 90% latency improvement and 2x lower peak memory usage.

Original languageEnglish (US)
Title of host publicationProceedings of ESPM2 2021
Subtitle of host publication6th International IEEE Workshop on Extreme Scale Programming Models and Middleware, Held in conjunction with SC 2021: The International Conference for High Performance Computing, Networking, Storage and Analysis
PublisherInstitute of Electrical and Electronics Engineers Inc.
Pages10-19
Number of pages10
ISBN (Electronic)9781665411400
DOIs
StatePublished - 2021
Externally publishedYes
Event6th International IEEE/ACM Workshop on Extreme Scale Programming Models and Middleware, ESPM2 2021 - St. Louis, United States
Duration: Nov 15 2021 → …

Publication series

NameProceedings of ESPM2 2021: 6th International IEEE Workshop on Extreme Scale Programming Models and Middleware, Held in conjunction with SC 2021: The International Conference for High Performance Computing, Networking, Storage and Analysis

Conference

Conference6th International IEEE/ACM Workshop on Extreme Scale Programming Models and Middleware, ESPM2 2021
Country/TerritoryUnited States
CitySt. Louis
Period11/15/21 → …

Keywords

  • AMPI
  • Asynchronous Tasking
  • Charm++
  • Communication Optimizations
  • Parallel Programming
  • RDMA

ASJC Scopus subject areas

  • Safety, Risk, Reliability and Quality
  • Hardware and Architecture
  • Software

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