Abstract
To better advise HPC application developers, we have implemented Faces, a nearest-neighbor microbenchmark that quantifies performance trade-offs. The Faces experiments presented here explore the following design choices: 1) fewer dependent messages versus more independent messages, 2) fewer fused GPU kernels versus more simple kernels, 3) number of GPU streams, 4) size of GPU thread blocks, and 5) linear versus blocked ordering of MPI ranks. We present weak-scaling performance of a latency-sensitive "small"per-rank domain and of a bandwidth-sensitive "large"per-rank domain, and we compare results for two high-performance computers with contrasting CPU, GPU, and interconnect architectures: Summit and Frontier. We find that using more independent messages tends to give better performance than using few dependent messages. We identify performance-portability recommendations for GPU streams and synchronization, but other aspects of performance show complicated dependence on problem size and computer.
Original language | English |
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Title of host publication | Proceedings of 2023 SC Workshops of the International Conference on High Performance Computing, Network, Storage, and Analysis, SC Workshops 2023 |
Publisher | Association for Computing Machinery |
Pages | 1070-1080 |
Number of pages | 11 |
ISBN (Electronic) | 9798400707858 |
DOIs | |
State | Published - Nov 12 2023 |
Event | 2023 International Conference on High Performance Computing, Network, Storage, and Analysis, SC Workshops 2023 - Denver, United States Duration: Nov 12 2023 → Nov 17 2023 |
Publication series
Name | ACM International Conference Proceeding Series |
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Conference
Conference | 2023 International Conference on High Performance Computing, Network, Storage, and Analysis, SC Workshops 2023 |
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Country/Territory | United States |
City | Denver |
Period | 11/12/23 → 11/17/23 |
Funding
This research used resources of the Oak Ridge Leadership Computing Facility (OLCF) at the Oak Ridge National Laboratory, which is supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC05-00OR22725. The OLCF Frontier Center of Excellence supported this research.
Keywords
- Design Trade-Offs
- GPU Kernels
- GPU Streams
- GPU Thread Blocks
- GPU-Aware MPI
- GPUs
- Kernel Fusion
- MPI
- Nearest-Neighbor Communication
- Overlap
- Performance Portability
- Pipelining
- Programming