Automatic generation of software pipelines for heterogeneous parallel systems

Pipelining is a well-known approach to increasing parallelism and performance. We address the problem of software pipelining for heterogeneous parallel platforms that consist of different multi-core and many-core processing units. In this context, pipelining involves two key steps -- partitioning an application into stages and mapping and scheduling the stages onto the processing units of the heterogeneous platform. We show that the inter-dependency between these steps is a critical challenge that must be addressed in order to achieve high performance. We propose an Automatic Heterogeneous Pipelining framework (AHP) that generates an optimized pipelined implementation of a program from an annotated unpipelined specification. Across three complex applications (image classification, object detection, and document retrieval) and two heterogeneous platforms (Intel Xeon multi-core CPUs with Intel MIC and NVIDIA GPGPU accelerators), AHP achieves a throughput improvement of up to 1.53x (1.37x on average) over a heterogeneous baseline that exploits data and task parallelism.