Today's trend to use accelerators like GPGPUs in heterogeneous computer systems has entailed several low-level APIs for accelerator programming. However, programming these APIs is often tedious and therefore unproductive. To tackle this problem, recent approaches employ directive-based high-level pro-gramming for accelerators. In this work, we present our first experiences with OpenACC, an API consisting of compiler directives to offload loops and regions of C/C++ and Fortran code to accelerators. We compare the performance of OpenACC to PGI Accelerator and OpenCL for two real-world applications and evaluate programmability and productivity. We find that OpenACC offers a promising ratio of development effort to performance and that a directive-based approach to program accelerators is more efficient than low-level APIs, even if suboptimal performance is achieved.
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机译：今天，使用像GPGPU中的加速器在异构计算机系统中使用的趋势已经为加速器编程进行了几个低级API。但是，编程这些API通常是乏味的，因此不生产。为了解决这个问题，最近的方法采用了基于指令的高级专业程序进行加速器。在这项工作中，我们向OpenACC提供了第一个经验，该APIA是由编译器指令组成的API，以将C / C ++和Fortran代码的卸载循环和区域提供给加速器。我们将OpenACC对PGI加速器和OpenCL的性能进行比较，以实现两个现实世界的应用，并评估可编程性和生产率。我们发现Openacc提供了对性能的有希望的比率，并且即使实现了次优的性能，也比低级别的API更有效地提供了一个基于指令的方案的方法。
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