介绍龙芯2号处理器设计及其性能测试结果.龙芯2号采用四发射超标量超流水结构。片内一级指令和数据高速缓存各64KB,片外二级高速缓存最多可达8MB.为了充分发挥流水线的效率,龙芯2号实现了先进的转移猜测、寄存器重命名、动态调度等乱序执行技术以及非阻塞的Cache访问和load Speculation等动态存储访问机制.龙芯2号处理器采用0.18gm的CMOS工艺实现,在正常电压下的最高工作频率为500MHz,500MHz时的实测功耗为3~5W.龙芯2号单精度峰值浮点运算速度为20亿a/秒,双精度浮点运算速度为10亿a/秒,SPECCPU2000的实测性能是龙芯1号的8~10倍,综合性能已经达到PentiumⅢ的水平.目前芯片样机能流畅运行完整的64位中文Linux操作系统,全功能的Mozilla浏览器、多媒体播放器和OpenOffice办公套件,可以满足绝大多数桌面应用的要求.
In this paper, the design and the result of performance analysis of the Godson-2 processor are presented. The Godson-2 implements a 4-way superscalar pipelined architecture, contains two 64KB L1 caches for instruction and data, and supports up to 8MB off-chip L2 cache. To improve the pipeline efficiency, The Godson-2 utilizes out-of-order executing technologies such as advanced branch prediction unit, register renaming and dynamic scheduler, and dynamic memory access mechanism like non-blocking cache and load speculation. The Godson-2 is implemented on 0.18um CMOS technology, with a maximum frequency of 500MHz under normal voltage and consumes 3-5 watts power under that frequency. The Godson-2 can perform one billion double-precision floating-point operations per second (two billion for single-precision), and the overall performance is comparable to Intel Pentium III with similar frequency. Presently a full Linux distribution (Debian) is running well on the Godson-2 prototype machines, including important desktop applications such as Mozilla web browsers, media players and OpenOffice.