An Interface for Abstracting Execution | P0058R1

The algorithms and execution policies specified by the Parallelism TS are designed to permit implementation on the broadest range of platforms. In addition to preemptive thread pools common on some platforms, implementations of these algorithms may want to take advantage of a number of mechanisms for parallel execution, including cooperative fibers, GPU threads, and SIMD vector units, among others. A suitable abstraction encapsulating the details of how work is created across such diverse platforms would be of significant value to parallel algorithm implementations. Furthermore, other constructs that expose parallelism to the programmer—including async and task_block—would benefit from a common abstraction for launching work. We believe that a suitably defined executor interface provides just such a facility.