OpenPiton

Abstract

Industry is building larger, more complex, manycore processors on the back of strong institutional knowledge, but academic projects face difficulties in replicating that scale. To alleviate these difficulties and to develop and share knowledge, the community needs open architecture frameworks for simulation, chip design, and software exploration that support extensibility, scalability, and configurability, alongside an established base of verification tools and supported software. In this article, we present OpenPiton, an open source framework for building scalable architecture research prototypes from one core to 500 million cores. OpenPiton is the world's first open source, general-purpose, multithreaded manycore processor, and framework. OpenPiton is highly configurable, providing a rich design space spanning a variety of hardware parameters that researchers can change. OpenPiton designs can be emulated on FPGAs, where they can run full-stack multiuser Debian Linux. OpenPiton is designed to scale to very large core fabrics, enabling researchers to measure operating system, compiler, and software scalability. The mature code-base reflects the complexity of an industrial-grade design and provides the necessary scripts to build new chips, making OpenPiton a natural choice for computer-aided design (CAD) research. OpenPiton has been validated with a 25-core chip prototype, named Piton, and is bolstered by a validation suite that has thousands of tests, providing an environment to test new hardware designs while verifying the correctness of the whole system. OpenPiton is being actively used in research both internally to Princeton and in the wider community, as well as being adopted in education, industry, and government settings.