Fpga-based prototype of a pram-on-chip processor

PRAM (Parallel Random Access Model) has been widely regarded a desirable parallel machine model for many years, but it is also believed to be "impossible in reality." As the new billion-transistor processor era begins, the eXplicit Multi-Threading (XMT) PRAM-On-Chip project is attempting to design an on-chip parallel processor that efficiently supports PRAM algorithms. This paper presents the first prototype of the XMT architecture that incorporates 64 simple in-order processors operating at 75MHz. The microarchitecture of the prototype is described and the performance is studied with respect to some micro-benchmarks. Using cycle accurate emulation, the projected performance of an 800MHz XMT ASIC processor is compared with AMD Opteron 2.6GHz, which uses similar area as would a 64-processor ASIC version of the XMT prototype. The results suggest that an only 800MHz XMT ASIC system outperforms AMD Opteron 2.6GHz, with speedups ranging between 1.57 and 8.56.