Flexdcp: a qos framework for cmp architectures

Current multicore architectures offer high throughput by increasing hardware resource utilization. As the number of cores in a multi-core system increases, providing Quality of Service (QoS) to appli-cations in addition to throughput is becoming an important prob-lem. In this work, we present FlexDCP, a framework that allows the Operating System (OS) to guarantee a QoS for each applica-tion running in a chip multiprocessor. FlexDCP directly estimates the performance of applications for different cache configurations instead of using indirect measures of performance like the num-ber of misses. This information allows the OS to convert QoS re-quirements into resource assignments. Consequently, it offers more flexibility to the OS as it can optimize different QoS metrics like per-application performance or global performance metrics such as fairness, weighted speed up or throughput. Our results show that FlexDCP is able to force applications in a workload to run at a certain percentage of their maximum performance in 94 % of the cases considered, being on average 1.48 % under the objective for remaining cases. When optimizing a global QoS metric like fairness, FlexDCP consistently outperforms traditional eviction policies like LRU, pseudo LRU and previous dynamic cache partitioning proposals for two-, four- and eight-core configurations. In an eight-core architecture FlexDCP obtains a fairness improvement of 10.1 % over Fair, the best policy in the literature optimizing fairness