CXL-Enabled QoS-Aware Tiered Memory System
Research Assistant, Advisor: Prof. Mosharaf Chowdhury
Sep 2023-Now
Tiered memory systems have widely been adopted to provide larger memory capacity in response to increasing memory demands from memory-intensive workloads. Although increased memory capacity allows more applications to be deployed, existing solutions for tiered memory systems are not built with Quality-of-Service (QoS) support. As a result, they often cannot meet service-level objectives (SLOs) when multiple applications share a tiered memory system. Specifically, applications suffer from local memory contention and memory bandwidth interference, two sources of performance unpredictability unique to tiered memory systems. Indeed, we observe application performance drops by 43% and 70% during severe memory contention and interference. This paper presents Mercury, a QoS-aware tiered memory system that provides predictable performance for coexisting memory-intensive applications, each with different SLOs. Mercury enables per-tier page reclamation to enforce application-level resource management. It leverages a novel admission control and real-time adaptation algorithm to maximize local memory utilization while mitigating memory interference. Evaluations with real-world applications show that Mercury can provide QoS guarantees among multiple applications sharing a tiered memory system with up to 53.4% improvement in performance.
Materials