Improving System Turnaround Time with Intel CAT by Identifying LLC Critical Applications

Abstract

Resource sharing is a major concern in current multicore processors. Among the shared system resources, the Last Level Cache (LLC) is one of the most critical, since destructive interference between applications accessing it implies more off-chip accesses to main memory, which incur long latencies that can severely impact the overall system performance. To help alleviate this issue, current processors implement huge LLCs, but even so, inter-application interference can harm the performance of a subset of the running applications when executing multiprogram workloads. For this reason, recent Intel processors feature Cache Allocation Technologies (CAT) to partition the cache and assign subsets of cache ways to groups of applications. This paper proposes the Critical-Aware (CA) LLC partitioning approach, which leverages CAT and improves the performance of multiprogram workloads, by identifying and protecting the applications whose performance is more damaged by LLC sharing. Experimental results show that CA improves turnaround time on average by 15%, and up to 40% compared to a baseline system without partitioning.