使用取指策略控制同时多线程处理器中个体线程的性能

Using Instruction Fetch Policy to Control Performance of a Thread in SMT Processors

当前,对同时多线程(Si multaneous Multithreading,SMT)处理器取指策略的研究大都集中在总体性能的优化上.文中提出一种新颖的SMT处理器取指策略(Controlling Performance of Individual Thread,CPIT),用于控制个体线程的执行.结果表明,对于模拟的所有负载,CPIT在94%以上的情况下都能保证受控线程获得期望性能.而对于失败的情况,受控线程的平均性能偏差不超过1.25%.此外,CPIT策略对处理器总体性能的影响并不大.与ICOUNT这种以优化性能为目标的取指策略相比,总体性能的平均降低不超过3%,而除受控线程外的其他线程的性能平均只降低了1.75%.

Currently, fetch policies in Simultaneous Multithreading （SMT） processors almost fo cus on overall performance optimization, and provide no control over how individual threads are executed. A novel fetch policy called CPIT （Controlling Performance of Individual Thread） is proposed to control the execution of a particular thread in SMT processors. Results show that for more than 94% of all cases measured, CPIT can control the execution and consequently achieve the desired performance for a given thread. For the failing cases, the average variance is within 1.25%. Furthermore, CPIT does not sacrifice overall performance of SMT processors severely. Compared to fetch policies orienting towards performance maximization such as ICOUNT, the average degradation of overall performance is not more than 3 % and the degradation of threads other than the given thread in performance is only 1.75%.