Designing architecture for general-purpose graphics processing units (GPGPUs) has been challenging because the hardware is expensive and labor-intensive to produce.
A new open-source tool from Georgia Tech, however, is making research more accessible for everyone.
Vortex is a reconfigurable GPGPU accelerator that uses an extended open-source reduced instruction set computer (RISC), an open architecture. By combining a GPGPU with RISC-V, the hardware can use the open programming framework OpenCL.
“Before RISC-V, building full-stack GPU hardware would have been an insurmountable task that only large companies would have had the resources to do,” said Blaise Tine, a School of Computer Science (SCS) Ph.D. student who leads the Vortex GPU. “One of the main design goals of this project is to support open-source tools across the board; software, compilers, simulators, synthesis, etc., to really make this platform as accessible as possible.”
Since the number of computer chip transistors is no longer expected to double every year as Moore’s law held up until the past few years, the semiconductor industry has been pushing specialized hardware to make up for performance gaps.
Now heterogeneous systems-on-chip provide powerful performance, but a lot of GPGPU research is restricted to simulation unless researchers can work with large companies on the actual hardware.
“Hardware design is extremely difficult and time-consuming, and before the emergence of RISC-V, there were no standardized ISA or software tools that guaranteed long-term support of open-source contributions like this,” said Tech alumnus Fares Elsabbagh.
Yet with the advent of open-source ISAs like RISC-V, and the programming framework OpenCL, the researchers saw an opportunity.
To support OpenCL on Vortex, the researchers used the open-source compiler POCL and extended it to support RISC-V and Vortex ISA. Being able to use OpenCL was a major breakthrough for Vortex because it allowed the processor to execute real applications. This has practical applications, such as running existing machine learning programs without having to rewrite the program.
“Vortex is built on industry-standard open-source tools and protocols, allowing researchers and companies to easily modify the design to their needs, and be able to easily evaluate it against other designs,” Elsabbagh said.
Vortex is already being used in student projects, and the researchers have plans to extend its capabilities. They also plan to expand the platform to cover all aspects of hardware acceleration, graphics, artificial intelligence, vision, and audio.
The researchers presented Vortex in the poster, Vortex: An Open Source Reconfigurable RISC-V GPGPU Accelerator for Architecture Research, at Hot Chips: A Symposium on High Performance Chips from Aug. 16-18. Tine and Elsabaggh wrote the paper with Tech studnets Apurve Chawda, Will Gulian, Yaotian Feng, Da Eun Shim, Priyadarshini Roshan, Ethan Lyons, Lingjun Zhu, School of Electrical and Computer Engineering Professor Sung Kyu Lim, and SCS Professor Hyesoon Kim.