Lightweight virtual memory support for many-core accelerators in heterogeneous embedded SoCs

Pirmin Vogel, Andrea Marongiu, Luca Benini

Abstract: While high-end heterogeneous systems are increasingly supporting heterogeneous uniform memory access (hUMA) as envisioned by the Heterogeneous System Architecture (HSA) foundation, their low-power counterparts targeting the embedded domain still lack basic features like virtual memory support for accelerators. As opposed to simply passing virtual address pointers, explicit data management involving copies is needed to share data between host processor and accelerators which hampers programmability and performance. In this work, we present a mixed hardware/software solution to enable lightweight virtual memory support for many-core accelerators in heterogeneous embedded systems-on-chip (SoCs). Based on an input/output translation lookaside buffer (IOTLB), efficiently managed by a kernel-level driver module running on the host, our solution features a considerably lower design complexity compared to conventional input/output memory management units. Using our evaluation platform based on the Xilinx Zynq-7000 SoC with a many-core accelerator implemented in the programmable logic, we demonstrate the effectiveness of our solution and the benefits of virtual memory support for embedded heterogeneous SoCs.