Ramp blue: A message-passing manycore system in FPGAs

We are developing a set of reusable design blocks and several prototype systems for emulation of multi-core architectures in FPGAs. RAMP Blue is the first of these prototypes and was designed to emulate a distributed-memory message-passing architecture. The system consists of 7681008 MicroBlaze cores in 64-84 Virtex-II Pro 70 FPGAs on 16-21 BEE2 boards, surpassing the milestone of 1000 cores in a standard 42U rack. An architecture based on point-to-point channels and switches using a combination of custom and generic hardware provides the functionality. Virtual-cut-through dimensional routing on one of two hybrid topologies with virtual channels provides the connectivity. A control network with a tree topology provides management and debugging capabilities. A software infrastructure consisting of GCC, uClinux and UPC allows running off-the-shelf applications and scientific benchmarks. Initial performance is encouraging for emulation purposes. In this paper we report on the design and implementation of RAMP Blue and discuss our experiences and lessons learned.