Acceleration of Control Intensive Applications on Coarse-Grained Reconfigurable Arrays for Embedded Systems

Embedded systems confront two opposite goals: low-power operation and high performance. The current trend to reach these goals is toward heterogeneous platforms, including multi-core architectures with heterogeneous cores and hardware accelerators. The latter can be divided into custom accelerators (e.g., ASICs) and programmable domain-specific cores (e.g., DSIPs). VWR2A [1] is a programmable architecture that integrates high computational density and low power memory structures. The flexibility of VWR2A allows a large portion of applications to be covered, resulting in better performance and energy efficiency than ASICs and general-purpose processors. However, while this has been well studied for data-intensive kernels, this is not the case for control-intensive kernels —code with complex if-else and nested loop structures. Traditionally, control-intensive code is left to be executed by the host processor. This situation unnecessarily restricts the potential impact of energy-efficient acceleration, especially at the application level. In this paper, we evaluate the performance and energy consumption of VWR2A for control-intensive code and compare it with an ARM Cortex-M4 processor and a RISC-V Ibex processor. The performance and energy consumption are evaluated at the kernel and application levels. Our results confirm that VWR2A is faster and more energy-efficient than the two considered general-purpose processors also for control-intensive code.