The 5th Generation 28nm 8-Core VLIW Elbrus-8C Processor Architecture

Elbrus is an explicitly parallel VLIW instruction set architecture developed by MCST. In this paper, we introduce the microarchitecture of the 5th generation 8-core Elbrus-8C processor implemented on 28nm. Elbrus-8C has 5x the peak performance for floating-point operations as compared with its predecessor, the Elbrus-4C processor, due to improved single-core performance and doubled number of cores. Microarchitecture enhancements include a 16 MB shared third-level cache, high-bandwidth, low-latency on-chip network, and a new cache coherence protocol. Elbrus-8C improves bandwidths of memory and I/O subsystems using four DDR3-1600 memory channels and a new 8 GBps full-duplex I/O link. The Elbrus-8C processor also offers energy saving, reliability, and die yield improvement mechanisms required due to large die area and power.