基于同时多线程的IFSBSMT取指策略研究

摘要

Fetch policy influences instuction throughput rate of computer processor directly. In the view of the shortages of unbalaned utilization of fetch bandwidth and high conflict rate of instruction queue, a new fetch policy named instruction flow speed based on simultaneous multithreading (IFSBSMT for short) was proposed. This strategy fetch takes the value of instrunctions per clock(IPC) to select the high priority thread and the method of prefetch instructions number to allocate fetch width. Meanwhile, IPC value for thread and L2 Cache miss rate are taken as the dual priority dynamic resource allocation mechanism to allocate the system resource for processors. The result shows IFSBMT can effectively improve the instruction fetch bandwidth and overcome the problems of instruction queue and resources waste, which can improve instruction throughput and abtain a better fetch fairness.%取指策略直接影响处理器的指令吞吐率.针对传统处理器取指策略存在取指带宽利用不均衡、指令队列冲突率高的缺点,提出基于同时多线程处理器的取指策略IFSBSMT.该策略以线程的IPC值为基础,速取优先级高的线程进行取指,并利用预取指令条数预算的方式分配取指带宽,采取线程IPC值和L2 Cache缺失率的双优先级动态资源分配机制分配处理器的系统资源.研究结果表明,IFSBSMT策略有效地解决了取指带宽、指令队列冲突及资源浪费问题,进一步提高了指令吞吐率,且具有较好的取指公平性.