Improving efficiency of semi‐direct møller–plesset second‐order perturbation methods through oversubscription on multiple nodes

The purpose of this work is to evaluate the efficacy of oversubscription, at the 1n, 2n, and 3n levels for n physical cores, on semi‐direct MP2 methods within NWChem when using two and three Intel nodes. Semi‐direct MP2 energy and gradient calculations were performed on chemical systems ranging from 824 to 1626 basis functions using the cc‐pVDZ basis set. Wall times for semi‐direct MP2 energies were reduced by as much as 36% using two nodes and 44% using three nodes compared to no oversubscription. Total energy consumed by the CPU and DRAM was also reduced by as much as 12% using two nodes and as much as 20% using three nodes when oversubscribing. MP2 gradient wall times improved by as much as 16% using two nodes and 18% using three nodes compared to execution at the 1n level; however, energy savings were insignificant. Intel performance‐counter data show a strong correlation between total wall time saved and less time spent in the idle state, indicating a more efficient use of the processors when oversubscribing. © 2019 Wiley Periodicals, Inc. A simple and effective method of oversubscription is used with semi‐direct Møller–Plesset second‐order perturbation (MP2) calculations on multiple nodes. Oversubscription is calling more virtual processes than physical CPUs. On two and three nodes, oversubscription significantly reduces execution times of semi‐direct MP2 energy and gradient calculations and total energy consumed of MP2 energy jobs. Oversubscribing leads to more efficient use of the CPUs, less idling and more work accomplished in a shorter period.