A HLS-Based Toolflow to Design Next-Generation Heterogeneous Many-Core Platforms with Shared Memory

This work describes how we use High-Level Synthesis to support design space exploration (DSE) of heterogeneous many-core systems. Modern embedded systems increasingly couple hardware accelerators and processing cores on the same chip, to trade specialization of the platform to an application domain for increased performance and energy efficiency. However, the process of designing such a platform is complex and error-prone, and requires skills on algorithmic aspects, hardware synthesis, and software engineering. DSE can partially be automated, and thus simplified, by coupling the use of HLS tools and virtual prototyping platforms. In this paper we enable the design space exploration of heterogeneous many-cores adopting a shared-memory architecture template, where communication and synchronization between the hardware accelerators and the cores happens through L1 shared memory. This communication infrastructure leverages a "zero-copy" scheme, which simplifies both the design process of the platform and the development of applications on top of it. Moreover, the shared-memory template perfectly fits the semantics of several high-level programming models, such as OpenMP. We provide programmers with simple yet powerful abstractions to exploit accelerators from within an OpenMP application, and propose a low-cost implementation of the necessary runtime support. An HLS-based automatic design flow is set up, to quickly explore the design space using a cycle-accurate virtual platform.