The Potential for a GPU-Like Overlay Architecture for FPGAs

Abstract

We propose a soft processor programming model and architecture inspired by graphics processing units (GPUs) that are well-matched to the strengths of FPGAs, namely, highly parallel and pipelinable computation. In particular, our soft processor architecture exploits multithreading, vector operations, and predication to supply a floating-point pipeline of 64 stages via hardware support for up to 256 concurrent thread contexts. The key new contributions of our architecture are mechanisms for managing threads and register files that maximize data-level and instruction-level parallelism while overcoming the challenges of port limitations of FPGA block memories as well as memory and pipeline latency. Through simulation of a system that (i) is programmable via NVIDIA's high-levelCglanguage, (ii) supports AMD's CTM r5xx GPU ISA, and (iii) is realizable on an XtremeData XD1000 FPGA-based accelerator system, we demonstrate the potential for such a system to achieve 100% utilization of a deeply pipelined floating-point datapath.

Exploring Trade-Offs between Specialized Dataflow Kernels and a Reusable Overlay in a Stereo Matching Case Study

“…Ovtcharov et al [38] add the concept of GPU-like multithreading to hide latencies of functional units and memory access by pipelining the execution of different threads. As proposed by Kingyens and Steffan [39] and brought forward by Convey with CHOMP [40] as successor to the vector processor utilized in this work, such a GPU-like architecture may be a promising architecture template for acceleration of server-and datacenter-scale computing tasks. From the programmers perspective, it offers more transparent ways to exploit parallelism in multiple dimensions than with the vector partitioning approach we had to specify explicitly.…”

FPGAs for Software Programmers

“…As an early attempt, Yiannacouras et al explored the use of a fine-grained scalable vector processor for code acceleration in embedded systems [YSR09]. Finally, a GPUlike overlay was proposed in [KS11] that demonstrate good performance while maintaining a compatible programming model for the users. It accepts simple C program as input and execute the code on the highly optimized vector processor on the FPGA for performance.…”

Dedicated object processor for mobile augmented reality - sailor assistance case study

“…It shows that lowfrequency dedicated architectures can be designed for this purpose. In [11], the authors present a GPU-inspired and multi-threaded softcore architecture, which is programmable with the NVIDIA Cg language. The aim is to simplify the use of FPGA-based acceleration boards for high-performance computing.…”