In Simultaneous Multithreading (SMT) processors, the instruction fetch policy implicitly determines shared resources allocation
among all the co-scheduled threads, and consequently affects throughput and fairness. However, prior work on fetch policies
almost focuses on throughput optimization. The issue of fairness between threads in progress rates is studied rarely.
In this paper, we take fairness as the optimization goal and propose an enhanced version of ICOUNT2.8 with better fairness
called ICOUNT2.8-fairness. Results show that using ICOUNT2.8-fairness, RPRrange (a fairness metric defined in this paper)
is less than 5% for all types of workloads, and the degradation of overall throughput is not more than 7%. Especially, for
two-thread MIX workload, ICOUNT2.8-fairness outperforms ICOUNT2.8 in throughput at the same time of achieving better fairness.
Keywords SMT - Instruction Fetch Policy - Throughput - Fairness
This work was supported by Chinese NSF under the grant No.60376018.