关键词: 超标量处理器, 同时多线程, 每周期完成的指令数（IPC）

Abstract: Simultaneous multithreading（SMT） is a technique that permits multiple independent threads to issue multiple instructions each cycle to a superscalar processor’s functional units.This technique can exploit both instruction-level and thread-level parallelism to improve the performance.Based on a 32-bit superscalar processor（Longtium R2），present the architecture equipped with the simultaneous multithreading technique.The data，gained from simulation，show that the throughput increment can be achieved without extensively changing the original structures or increasing the additional execution units of a superscalar processor.After using the SMT technique，the processor can achieves up to 50% performance improvement，although influenced by some restrictions.

Key words: superscalar processor, simultaneous multithreading, instruction per cycle