A Pattern for Overlapping Communication and Computation with OpenMP\(^*\) Target Directives
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OpenMP\(^*\) 4.0 introduced initial support for heterogeneous devices. OpenMP 4.5 improved programmability and added capabilities for asynchronous device kernel offload and data transfer management. However, the programmers are still burdened to optimize data transfer for improved performance and to deal with the limited amount of memory on the target device. This work presents a pipelining concept to efficiently overlap communication and computation using the OpenMP 4.5 target directives. Our evaluation of two key HPC kernels shows performance improvements of up to 24% and the ability to process data larger than device memory.
Parts of this work were funded by the German Federal Ministry of Research and Education (BMBF) under Grant Number 01IH13008A (ELP). Simulations were performed with computing resources granted by JARA-HPC from RWTH Aachen University under project jara0001.
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