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Evaluating the performance of parallel subsurface simulators: An illustrative example with PFLOTRAN.

Hammond GE, Lichtner PC, Mills RT - Water Resour Res (2014)

Bottom Line: [1] To better inform the subsurface scientist on the expected performance of parallel simulators, this work investigates performance of the reactive multiphase flow and multicomponent biogeochemical transport code PFLOTRAN as it is applied to several realistic modeling scenarios run on the Jaguar supercomputer.PFLOTRAN scales well (with regard to strong scaling) for three realistic problem scenarios: (1) in situ leaching of copper from a mineral ore deposit within a 5-spot flow regime, (2) transient flow and solute transport within a regional doublet, and (3) a real-world problem involving uranium surface complexation within a heterogeneous and extremely dynamic variably saturated flow field.Weak scalability is discussed in detail for the regional doublet problem, and several difficulties with its interpretation are noted.

View Article: PubMed Central - PubMed

Affiliation: Applied Systems Analysis and Research, Sandia National Laboratories Albuquerque, New Mexico, USA.

ABSTRACT

[1] To better inform the subsurface scientist on the expected performance of parallel simulators, this work investigates performance of the reactive multiphase flow and multicomponent biogeochemical transport code PFLOTRAN as it is applied to several realistic modeling scenarios run on the Jaguar supercomputer. After a brief introduction to the code's parallel layout and code design, PFLOTRAN's parallel performance (measured through strong and weak scalability analyses) is evaluated in the context of conceptual model layout, software and algorithmic design, and known hardware limitations. PFLOTRAN scales well (with regard to strong scaling) for three realistic problem scenarios: (1) in situ leaching of copper from a mineral ore deposit within a 5-spot flow regime, (2) transient flow and solute transport within a regional doublet, and (3) a real-world problem involving uranium surface complexation within a heterogeneous and extremely dynamic variably saturated flow field. Weak scalability is discussed in detail for the regional doublet problem, and several difficulties with its interpretation are noted.

No MeSH data available.


Number of flow and geochemical transport linear BCGS solver iterations in simulation versus number of processes employed for the IFRC scenario.
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fig15: Number of flow and geochemical transport linear BCGS solver iterations in simulation versus number of processes employed for the IFRC scenario.

Mentions: [70]From Figure 3, it is clear that, although superlinear at small numbers of processes (see also Figure 11), the scaling of the flow solution is far from ideal at large process counts, tailing off at 128 processes ( dofs per process). The figure demonstrates that the degradation in parallel performance is mainly attributable to performance degradation in the linear Krylov solver likely due to increased time spent in global reductions and a growth in linear solver iterations (see Figure 15). Note that growing linear solver iterations increases the number of global reductions, compounding performance degradation attributable to global reductions. The residual and Jacobian evaluations scale well out to 1024–2048 processes.


Evaluating the performance of parallel subsurface simulators: An illustrative example with PFLOTRAN.

Hammond GE, Lichtner PC, Mills RT - Water Resour Res (2014)

Number of flow and geochemical transport linear BCGS solver iterations in simulation versus number of processes employed for the IFRC scenario.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4257577&req=5

fig15: Number of flow and geochemical transport linear BCGS solver iterations in simulation versus number of processes employed for the IFRC scenario.
Mentions: [70]From Figure 3, it is clear that, although superlinear at small numbers of processes (see also Figure 11), the scaling of the flow solution is far from ideal at large process counts, tailing off at 128 processes ( dofs per process). The figure demonstrates that the degradation in parallel performance is mainly attributable to performance degradation in the linear Krylov solver likely due to increased time spent in global reductions and a growth in linear solver iterations (see Figure 15). Note that growing linear solver iterations increases the number of global reductions, compounding performance degradation attributable to global reductions. The residual and Jacobian evaluations scale well out to 1024–2048 processes.

Bottom Line: [1] To better inform the subsurface scientist on the expected performance of parallel simulators, this work investigates performance of the reactive multiphase flow and multicomponent biogeochemical transport code PFLOTRAN as it is applied to several realistic modeling scenarios run on the Jaguar supercomputer.PFLOTRAN scales well (with regard to strong scaling) for three realistic problem scenarios: (1) in situ leaching of copper from a mineral ore deposit within a 5-spot flow regime, (2) transient flow and solute transport within a regional doublet, and (3) a real-world problem involving uranium surface complexation within a heterogeneous and extremely dynamic variably saturated flow field.Weak scalability is discussed in detail for the regional doublet problem, and several difficulties with its interpretation are noted.

View Article: PubMed Central - PubMed

Affiliation: Applied Systems Analysis and Research, Sandia National Laboratories Albuquerque, New Mexico, USA.

ABSTRACT

[1] To better inform the subsurface scientist on the expected performance of parallel simulators, this work investigates performance of the reactive multiphase flow and multicomponent biogeochemical transport code PFLOTRAN as it is applied to several realistic modeling scenarios run on the Jaguar supercomputer. After a brief introduction to the code's parallel layout and code design, PFLOTRAN's parallel performance (measured through strong and weak scalability analyses) is evaluated in the context of conceptual model layout, software and algorithmic design, and known hardware limitations. PFLOTRAN scales well (with regard to strong scaling) for three realistic problem scenarios: (1) in situ leaching of copper from a mineral ore deposit within a 5-spot flow regime, (2) transient flow and solute transport within a regional doublet, and (3) a real-world problem involving uranium surface complexation within a heterogeneous and extremely dynamic variably saturated flow field. Weak scalability is discussed in detail for the regional doublet problem, and several difficulties with its interpretation are noted.

No MeSH data available.