Straightforward Heterogeneous Computing with the oneAPI Coexecutor Runtime

Heterogeneous systems are the core architecture of most computing systems, from high-performance computing nodes to embedded devices, due to their excellent performance and energy efficiency. Efficiently programming these systems has become a major challenge due to the complexity of their architectures and the efforts required to provide them with co-execution capabilities that can fully exploit the applications. There are many proposals to simplify the programming and management of acceleration devices and multi-core CPUs. However, in many cases, portability and ease of use compromise the efficiency of different devices-even more so when co-executing. Intel oneAPI, a new and powerful standards-based unified programming model, built on top of SYCL, addresses these issues. In this paper, oneAPI is provided with co-execution strategies to run the same kernel between different devices, enabling the exploitation of static and dynamic policies. This work evaluates the performance and energy efficiency for a well-known set of regular and irregular HPC benchmarks, using two heterogeneous systems composed of an integrated GPU and CPU. Static and dynamic load balancers are integrated and evaluated, highlighting single and co-execution strategies and the most significant key points of this promising technology. Experimental results show that co-execution is worthwhile when using dynamic algorithms and improves the efficiency even further when using unified shared memory.