基于门限和数据Cache预测的同时多线程调度策略

Improving SMT Thread Schedule Policy Based on Threshold and Data Cache Prediction

同时多线程处理器每周期从多个活动线程取指令执行,极大地提高了处理器的性能,线程调度策略直接影响SMT处理器的性能。详细分析了SMT中导致指令队列阻塞的各种因素,以及它们对系统性能的影响。在ICOUNT取指调度策略的基础上,提出了一种基于门限的线程调度策略,它考虑了各种导致IQ阻塞的因素及其对IQ效率的影响程度,相对ICOUTNT策略,将IPC平均提高了4.141%。在此基础上,通过统计分析两次数据Cache缺失之间的距离,提出了数据Cache预测技术,又将IPC提高了0.65%。

In SMT architecture, instructions can be fetched from multi-thread simultaneously to increase system performance. Thread schedule policy is an important case in point. Factors affect instruction queue efficiency are analyzed in detail. And on the base of the popular ICOUNT policy, an improving thread schedule policy based on threshold is proposed. In the policy, main factors affect queue efficiency are taken into account according to their influence degree. After simulation, the IPC value is increased by 4. 141% compared with ICOUTNT policy. Afterwards, the distance between twice data cache miss are statistically analyzed, and a new data cache miss prediction method is presented and used in the threshold based thread schedule policy, which allows an additional IPC value increase by 0.65%.