An Instruction Fetch Policy Based on Multiple Fetch Priorities for SMT Processors
Zhang Min-xuan · Dianzi xuebao · 2006
In Simultaneous Multithreading(SMT) processors,co-scheduled threads share the processor′s resources,but at the same time compete for them.A thread missing in L2 cache may occupy most of available resources for a long time,causing other threads run slower than they could or even stall because of lack of resources.As a result,the overall performance of SMT processors is degraded.In this paper,we propose a novel fetch policy called MFP(Multiple Fetch Priorities) to prevent the negative effects caused by L2 cache misses.Results show that our policy outperforms previously proposed fetch policies for all types of workloads,especially for memory bounded workloads,whether using IPC as a metric or using the harmonic mean as a metric.Results also tell that our policy shows different degrees of improvement over other fetch policies.The increment over PDG is greatest,reaching 19.2% in IPC and 27.7% in Hmean on average.