title: Saving time and energy with oversubscription and semi-direct Møller-Plesset second order perturbation methods.
abstract: In this work, the effect of oversubscription is evaluated, via calling 2n, 3n, or 4n processes for n physical cores, on semi-direct MP2 energy and gradient calculations and RI-MP2 energy calculations with the cc-pVTZ basis using NWChem. Results indicate that on both Intel and AMD platforms, oversubscription reduces total time to solution on average for semi-direct MP2 energy calculations by 25-45% and reduces total energy consumed by the CPU and DRAM on average by 10-15% on the Intel platform. Semi-direct gradient time to solution is shortened on average by 8-15% and energy consumption is decreased by 5-10%. Linear regression analysis shows a strong correlation between time to solution and total energy consumed. Oversubscribing during RI-MP2 calculations results in performance degradations of 30-50% at the 4n level. © 2017 Wiley Periodicals, Inc.
authors.affiliation: Department of Chemistry, Iowa State University, Ames, Iowa, 50011.
authors.forename: Ellie L
authors.identifier: 0000-0002-8135-5641
authors.initials: EL
authors.lastname: Fought
authors.affiliation: Department of Modeling, Simulation, and Visualization Engineering, Old Dominion University, Norfolk, Virginia, 23529.
authors.forename: Vaibhav
authors.initials: V
authors.lastname: Sundriyal
authors.affiliation: Department of Modeling, Simulation, and Visualization Engineering, Old Dominion University, Norfolk, Virginia, 23529.
authors.forename: Masha
authors.initials: M
authors.lastname: Sosonkina
authors.affiliation: Department of Chemistry, Iowa State University, Ames, Iowa, 50011.
authors.forename: Theresa L
authors.initials: TL
authors.lastname: Windus
keywords: MP2; energy savings; multithreading; oversubscription; semi-direct algorithms