TY  - JOUR
T1  - MSHR-Aware Dynamic Warp Scheduler for High Performance GPUs
AU  - Kim, Gwang Bok 
AU  - Kim, Jong Myon 
AU  - Kim, Cheol Hong 
JO  - KIPS Transactions on Computer and Communication Systems
PY  - 2019
DA  - 2019/1/30
DO  - https://doi.org/10.3745/KTCCS.2019.8.5.111
KW  - GPU
KW  - Warp Scheduling
KW  - Cache
KW  - MSHR
KW  - Parallelism
AB  - Recent graphic processing units (GPUs) provide high throughput by using powerful hardware resources. However, massive memory accesses cause GPU performance degradation due to cache inefficiency. Therefore, the performance of GPU can be improved by reducing thread parallelism when cache suffers memory contention. In this paper, we propose a dynamic warp scheduler which controls thread parallelism according to degree of cache contention. Usually, the greedy then oldest (GTO) policy for issuing warp shows lower parallelism than loose round robin (LRR) policy. Therefore, the proposed warp scheduler employs the LRR warp scheduling policy when Miss Status Holding Register(MSHR) utilization is low. On the other hand, the GTO policy is employed in order to reduce thread parallelism when MSHRs utilization is high. Our proposed technique shows better performance compared with LRR and GTO policy since it selects efficient scheduling policy dynamically. According to our experimental results, our proposed technique provides IPC improvement by 12.8% and 3.5% over LRR and GTO on average, respectively.