Techniques to Save Energy in Heterogeneous Multicore Architectures under QoS Constraints
A first contribution of the thesis is a resource management technique for single-threaded applications that uses core type (e.g. big or little cores) and V-F settings as a configuration space to select a configuration, for each iteration, based on the execution-time prediction of future iterations and computational deadlines. The thesis shows that an energy saving of 25% over the race-to-idle state-of-the-art technique is achieved without missing any deadlines. This scheme incurs only 0.6% and 0.8% of timing and energy overheads, respectively. A second contribution of the thesis is a novel resource-management policy for multi-threaded applications. Here, the configuration space is extended to also consider the thread count, i.e., the number of cores assigned to multi-threaded applications. The proposed technique first chooses the most energy-efficient configuration that meets the computational deadline. Since an iteration typically finishes before the deadline, the proposed technique collects the generated execution-time slack over subsequent iterations with the goal of selecting a configuration that can save more energy. To allow for on-line exploration of the configuration space, at low overhead, a third contribution of the thesis is an online, low-overhead prediction method based on interpolation, that measures the execution statistics at end points of each configuration-space dimension and interpolates the values at intermediate configurations. Overall, the proposed technique saves 61% energy compared to the state-of-the-art
race-to-idle technique without missing any deadlines. Further, it only incurs 0.6% and 0.7% of timing and energy overheads, respectively.
Muhammad Waqar Azhar
Chalmers, Data- och informationsteknik, Datorteknik
SLOOP: QoS-Supervised Loop Execution to Reduce Energy on Heterogeneous Architectures
ACM Transactions on Architecture and Code Optimization,; Vol. 14(2017)p. Article No. 41-
Artikel i vetenskaplig tidskrift
M Waqar Azhar, Miquel Pericas, Per Stenström “SaC: Exploiting Execution-Time Slack to Save Energy in Heterogeneous Multicore Sys- tems” Technical report 2019:02, ISSN 1652-926X
Meeting Challenges in Computer Architecture (MECCA)
Europeiska kommissionen (EU) (EC/FP7/340328), 2014-02-01 -- 2019-01-31.
Informations- och kommunikationsteknik
Opponent: Dr. Sven Karlsson, Ericsson Research