relation: http://eprints.imtlucca.it/3573/ title: Workload Change Point Detection for Runtime Thermal Management of Embedded Systems creator: Das, Anup creator: Merrett, Geoff V. creator: Tribastone, Mirco creator: Al-Hashimi, Bashir M. subject: QA76 Computer software description: Applications executed on multicore embedded systems interact with system software [such as the operating system (OS)] and hardware, leading to widely varying thermal profiles which accelerate some aging mechanisms, reducing the lifetime reliability. Effectively managing the temperature therefore requires: 1) autonomous detection of changes in application workload and 2) appropriate selection of control levers to manage thermal profiles of these workloads. In this paper, we propose a technique for workload change detection using density ratio-based statistical divergence between overlapping sliding windows of CPU performance statistics. This is integrated in a runtime approach for thermal management, which uses reinforcement learning to select workload-specific thermal control levers by sampling on-board thermal sensors. Identified control levers override the OSs native thread allocation decision and scale hardware voltage-frequency to improve average temperature, peak temperature, and thermal cycling. The proposed approach is validated through its implementation as a hierarchical runtime manager for Linux, with heuristic-based thread affinity selected from the upper hierarchy to reduce thermal cycling and learningbased voltage-frequency selected from the lower hierarchy to reduce average and peak temperatures. Experiments conducted with mobile, embedded, and high performance applications on ARM-based embedded systems demonstrate that the proposed approach increases workload change detection accuracy by an average 3.4×, reducing the average temperature by 4 °C-25 °C, peak temperature by 6 °C-24 °C, and thermal cycling by 7%-35% over state-of-the-art approaches. publisher: IEEE date: 2016 type: Article type: PeerReviewed identifier: Das, Anup and Merrett, Geoff V. and Tribastone, Mirco and Al-Hashimi, Bashir M. Workload Change Point Detection for Runtime Thermal Management of Embedded Systems. IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems, 35 (8). pp. 1358-1371. ISSN 0278-0070 (2016) relation: http://doi.org/10.1109/TCAD.2015.2504875 relation: doi:10.1109/TCAD.2015.2504875