Fine‐grain data management directory for OpenMP 4.0 and OpenACC

Abstract

SUMMARYToday's trend to use accelerators in heterogeneous systems forces a paradigm shift in programming models. The use of low-level APIs for accelerator programming is tedious and not intuitive for casual programmers. To tackle this problem, recent approaches focused on high-level directive-based models, with a standardization effort made with OpenACC and the directives for accelerator in the latest OpenMP 4.0 release. The pragmas for data management automatically handle data exchange between the host and the device. To keep the runtime simple and efficient, severe restrictions hinder the use of these pragmas. To address this issue, we propose the design for a directory, along with a reduced runtime application binary interface, to handle correctly data management in these standards. A few improvements to our directory allow a more flexible use of data management pragmas, with negligible overhead. Our design fits a multi-accelerator system.

DawnCC

“…Annotation systems. Annotation systems such as OpenMP 4.0 [Jaeger et al 2015], OpenSs [Meenderinck and Juurlink 2011], and Open- ACC Standard [2013] are a simple, yet powerful alternative to the development of high-performance software. Such systems are not a programming language per se; rather, they work as a metalanguage, which, once combined with a host language, typically Fortran, or C, let developers inject parallel semantics into its standard syntax.…”

“…And currently, directive-based annotation systems stand out among the different techniques used to program these machines. Examples of such systems include OpenMP [Jaeger et al 2015], OpenACC [OpenACC Standard 2013], OpenHMPP [Andión et al 2016], OpenMPC [Lee and Eigenmann 2010], and OpenSs [Meenderinck and Juurlink 2011]. The annotation-based programming model is simple yet appealing: annotations are a metalanguage, which give developers the ability to grant parallel semantics to syntax originally written to run sequentially.…”

Parallel computing on graphics processing units and heterogeneous platforms

“…In , the authors propose the design of a directory, along with a reduced runtime application binary interface, to handle data management between a host and accelerators in the OpenMP 4.0 and OpenACC standards. Some extensions were added to the directory to allow more flexibility when handling subarrays in the data clauses, including support for unstructured data lifetime.…”