| OpenCL has emerged as a standard programming model for heterogeneous systems. Recent work combining OpenCL and FPGAs has focused on high-level synthesis. Building a complete OpenCL FPGA system requires more than just high-level synthesis. This work introduces a reusable OpenCL infrastructure for FPGAs that complements previous work and specifically targets a key architectural element—the memory interface. An Aggregating Memory Controller that aims to maximize bandwidth to external, large, high-latency, high-bandwidth memories and a template Processing Array with soft-processor and hand-coded hardware elements are designed, simulated, and implemented on an FPGA. Two micro-benchmarks were run on both the soft-processor elements and the hand-coded hardware elements to exercise the Aggregating Memory Controller. The micro-benchmarks were simulated as well as implemented in a hardware prototype. Memory bandwidth results for the system show that the external memory interface can be saturated and the high-latency can be effectively hidden using the Aggregating Memory Controller. |
