Vortex Brings the RISC-V ISA to the World of OpenCL-Compatible General-Purpose GPUs

A team of developers from Georgia Tech have created a general-purpose graphics processing unit (GPGPU) implementation, compatible with the popular OpenCL programming framework, using the free and open source RISC-V instruction set architecture: Vortex.

"The current challenges in technology scaling are pushing the semiconductor industry towards hardware specialisation, creating a proliferation of heterogeneous systems-on-chip, delivering orders of magnitude performance and power benefits compared to traditional general-purpose architectures," the researchers claim in the abstract to their paper. "This transition is getting a significant boost with the advent of RISC-V with its unique modular and extensible ISA, allowing a wide range of low-cost processor designs for various target applications.

"In addition,OpenCL is currently the most widely adopted programming framework for heterogeneous platforms available on mainstream CPUs, GPUs, as well as FPGAs and custom DSP. In this work, we present Vortex, a RISC-V General-Purpose GPU that supports OpenCL. Vortex implements a SIMT architecture with a minimal ISA extension to RISC-V that enables the execution of OpenCL programs. We also extended OpenCL runtime framework to use the new ISA."

Evaluated on a 15nm process node, Vortex proved capable through a range of benchmarks - and, the researchers promise, will be made available to the public under an open licence once blind review of the work has been completed. "We believe that an Open Source version of [this] RISC-V GPGPU will enrich the RISC-V ecosystem," they explain, "and accelerate other researchers that study GPGPUs in wider topics since the entire software stack is also based on Open Source implementations."

The full paper describing Vortex is available on arXiv.org now under open access terms.