Publications

Clausen, Jonathan C.; Brunini, Victor B.; Forster, Christopher J.; Noble, David R.; Trott, Christian R.; Hammond, Simon D.; Hoemmen, Mark F.; Lin, Paul L.

Abstract not provided.

Bennett, Janine C.; Wilke, Jeremiah J.; Slattengren, Nicole S.; Teranishi, Keita T.; Lin, Paul L.; Sjaardema, Gregory D.; Kolla, Hemanth K.; Knight, Samuel K.

Abstract not provided.

Lin, Paul L.; Shadid, John N.; Phillips, Edward G.; Pawlowski, Roger P.

Abstract not provided.

Lecture Notes in Computational Science and Engineering

Sala, Marzio; Lin, Paul L.; Shadid, John N.; Tuminaro, Raymond S.

We report on algebraic multilevel preconditioners for the parallel solution of linear systems arising from a Newton procedure applied to the finite-element (FE) discretization of the incompressible Navier-Stokes equations. We focus on the issue of how to coarsen FE operators produced from high aspect ratio elements.

Lin, Paul L.; Shadid, John N.; Phillips, Edward G.; Hu, Jonathan J.; Cyr, Eric C.; Pawlowski, Roger P.; Tsuji, Paul T.; Sondak, David S.

Abstract not provided.

Lin, Paul L.; Shadid, John N.; Phillips, Edward G.; Pawlowski, Roger P.

Abstract not provided.

Tuminaro, Raymond S.; Hu, Jonathan J.; Prokopenko, Andrey V.; Siefert, Christopher S.; Tsuji, Paul H.; Boman, Erik G.; Cyr, Eric C.; Lin, Paul L.; Shadid, John N.

Abstract not provided.

Lin, Paul L.; Hammond, Simon D.

Abstract not provided.

Rajan, Mahesh R.; Vaughan, Courtenay T.; Barrett, Richard F.; Doerfler, Douglas W.; Lin, Paul L.; Pedretti, Kevin P.; Hemmert, Karl S.

Abstract not provided.

Rajan, Mahesh R.; Vaughan, Courtenay T.; Doerfler, Douglas W.; Lin, Paul L.; Pedretti, Kevin P.

Abstract not provided.

Rajan, Mahesh R.; Vaughan, Courtenay T.; Doerfler, Douglas W.; Lin, Paul L.; Pedretti, Kevin P.; Barrett, Richard F.; Hemmert, Karl S.

Abstract not provided.

Concurreny and Computation: Practice and Experience

Rajan, Mahesh R.; Vaughan, Courtenay T.; Doerfler, Douglas W.; Barrett, Richard F.; Lin, Paul L.; Pedretti, Kevin P.; Hemmert, Karl S.

Abstract not provided.

Baker, Gavin M.; Bettencourt, Matthew T.; Bova, S.W.; franko, ken f.; Gamell, Marc G.; Grant, Ryan E.; Hammond, Simon D.; Hollman, David S.; Knight, Samuel K.; Kolla, Hemanth K.; Lin, Paul L.; Olivier, Stephen O.; Sjaardema, Gregory D.; Slattengren, Nicole L.; Teranishi, Keita T.; Wilke, Jeremiah J.; Bennett, Janine C.; Clay, Robert L.; kale, laxkimant k.; Jain, Nikhil J.; Mikida, Eric M.; Aiken, Alex A.; Bauer, Michael B.; Lee, Wonchan L.; Slaughter, Elliott S.; Treichler, Sean T.; Berzins, Martin B.; Harman, Todd H.; humphreys, alan h.; schmidt, john s.; sunderland, dan s.; Mccormick, Pat M.; gutierrez, samuel g.; shulz, martin s.; Gamblin, Todd G.; Bremer, Peer-Timo B.

Abstract not provided.

Baker, Gavin M.; Bettencourt, Matthew T.; Bova, S.W.; franko, ken f.; Gamell, Marc G.; Grant, Ryan E.; Hammond, Simon D.; Hollman, David S.; Knight, Samuel K.; Kolla, Hemanth K.; Lin, Paul L.; Olivier, Stephen O.; Sjaardema, Gregory D.; Slattengren, Nicole L.; Teranishi, Keita T.; Wilke, Jeremiah J.; Bennett, Janine C.; Clay, Robert L.; kale, laxkimant k.; Jain, Nikhil J.; Mikida, Eric M.; Aiken, Alex A.; Bauer, Michael B.; Lee, Wonchan L.; Slaughter, Elliott S.; Treichler, Sean T.; Berzins, Martin B.; Harman, Todd H.; humphreys, alan h.; schmidt, john s.; sunderland, dan s.; Mccormick, Pat M.; gutierrez, samuel g.; shulz, martin s.; Gamblin, Todd G.; Bremer, Peer-Timo B.

This report provides in-depth information and analysis to help create a technical road map for developing next-generation programming models and runtime systems that support Advanced Simulation and Computing (ASC) work- load requirements. The focus herein is on asynchronous many-task (AMT) model and runtime systems, which are of great interest in the context of "Oriascale7 computing, as they hold the promise to address key issues associated with future extreme-scale computer architectures. This report includes a thorough qualitative and quantitative examination of three best-of-class AIM] runtime systems – Charm-++, Legion, and Uintah, all of which are in use as part of the Centers. The studies focus on each of the runtimes' programmability, performance, and mutability. Through the experiments and analysis presented, several overarching Predictive Science Academic Alliance Program II (PSAAP-II) Asc findings emerge. From a performance perspective, AIV runtimes show tremendous potential for addressing extreme- scale challenges. Empirical studies show an AM runtime can mitigate performance heterogeneity inherent to the machine itself and that Message Passing Interface (MP1) and AM11runtimes perform comparably under balanced conditions. From a programmability and mutability perspective however, none of the runtimes in this study are currently ready for use in developing production-ready Sandia ASC applications. The report concludes by recommending a co- design path forward, wherein application, programming model, and runtime system developers work together to define requirements and solutions. Such a requirements-driven co-design approach benefits the community as a whole, with widespread community engagement mitigating risk for both application developers developers. and high-performance computing runtime systein

Bettencourt, Matthew T.; Kramer, Richard M.; Cartwright, Keith C.; Phillips, Edward G.; Ober, Curtis C.; Pawlowski, Roger P.; Swan, Matthew S.; Kalashnikova, Irina; Phipps, Eric T.; Conde, Sidafa C.; Cyr, Eric C.; Ulmer, Craig D.; Kordenbrock, Todd H.; Levy, Scott L.; Templet, Gary J.; Hu, Jonathan J.; Lin, Paul L.; Glusa, Christian A.; Siefert, Christopher S.; Glass, Micheal W.

This report documents the outcome from the ASC ATDM Level 2 Milestone 6358: Assess Status of Next Generation Components and Physics Models in EMPIRE. This Milestone is an assessment of the EMPIRE (ElectroMagnetic Plasma In Realistic Environments) application and three software components. The assessment focuses on the electromagnetic and electrostatic particle-in-cell solu- tions for EMPIRE and its associated solver, time integration, and checkpoint-restart components. This information provides a clear understanding of the current status of the EMPIRE application and will help to guide future work in FY19 in order to ready the application for the ASC ATDM L 1 Milestone in FY20. It is clear from this assessment that performance of the linear solver will have to be a focus in FY19.

Cook, Jeanine C.; Edwards, Harold C.; Dinge, Dennis D.; Glass, Micheal W.; Hammond, Simon D.; Hoekstra, Robert J.; Lin, Paul L.; Rajan, Mahesh R.; Trott, Christian R.; Vaughan, Courtenay T.

Abstract not provided.

Hammond, Simon D.; Trott, Christian R.; Lin, Paul L.; Vaughan, Courtenay T.; Cook, Jeanine C.; Dinge, Dennis D.; Pase, Douglas M.; Benner, R.E.; Hoekstra, Robert J.

Abstract not provided.

Trott, Christian R.; Hammond, Simon D.; Dinge, Dennis D.; Lin, Paul L.; Vaughan, Courtenay T.; Cook, Jeanine C.; Rajan, Mahesh R.; Edwards, Harold C.; Hoekstra, Robert J.

For the FY15 ASC L2 Trilab Codesign milestone Sandia National Laboratories performed two main studies. The first study investigated three topics (performance, cross-platform portability and programmer productivity) when using OpenMP directives and the RAJA and Kokkos programming models available from LLNL and SNL respectively. The focus of this first study was the LULESH mini-application developed and maintained by LLNL. In the coming sections of the report the reader will find performance comparisons (and a demonstration of portability) for a variety of mini-application implementations produced during this study with varying levels of optimization. Of note is that the implementations utilized including optimizations across a number of programming models to help ensure claims that Kokkos can provide native-class application performance are valid. The second study performed during FY15 is a performance assessment of the MiniAero mini-application developed by Sandia. This mini-application was developed by the SIERRA Thermal-Fluid team at Sandia for the purposes of learning the Kokkos programming model and so is available in only a single implementation. For this report we studied its performance and scaling on a number of machines with the intent of providing insight into potential performance issues that may be experienced when similar algorithms are deployed on the forthcoming Trinity ASC ATS platform.

Lin, Paul L.; Shadid, John N.; Hu, Jonathan J.; Pawlowski, Roger P.; Cyr, Eric C.; Prokopenko, Andrey V.

Abstract not provided.

Concurrency and Computation. Practice and Experience

Lin, Paul L.; Heroux, Michael A.; Williams, Alan B.; Barrett, Richard F.

The performance of a large-scale, production-quality science and engineering application (‘app’) is often dominated by a small subset of the code. Even within that subset, computational and data access patterns are often repeated, so that an even smaller portion can represent the performance-impacting features. If application developers, parallel computing experts, and computer architects can together identify this representative subset and then develop a small mini-application (‘miniapp’) that can capture these primary performance characteristics, then this miniapp can be used to both improve the performance of the app as well as provide a tool for co-design for the high-performance computing community. However, a critical question is whether a miniapp can effectively capture key performance behavior of an app. This study provides a comparison of an implicit finite element semiconductor device modeling app on unstructured meshes with an implicit finite element miniapp on unstructured meshes. The goal is to assess whether the miniapp is predictive of the performance of the app. Finally, single compute node performance will be compared, as well as scaling up to 16,000 cores. Results indicate that the miniapp can be reasonably predictive of the performance characteristics of the app for a single iteration of the solver on a single compute node.

Barrett, Richard F.; Crozier, Paul C.; Doerfler, Douglas W.; Hammond, Simon D.; Heroux, Michael A.; Lin, Paul L.; Trucano, Timothy G.; Vaughan, Courtenay T.; Williams, Alan B.

Abstract not provided.

Journal of Parallel and Distributed Computing

Barrett, R.F.; Crozier, Paul C.; Doerfler, Douglas W.; Heroux, Michael A.; Lin, Paul L.; Thornquist, Heidi K.; Trucano, Timothy G.; Vaughan, Courtenay T.

Computational science and engineering application programs are typically large, complex, and dynamic, and are often constrained by distribution limitations. As a means of making tractable rapid explorations of scientific and engineering application programs in the context of new, emerging, and future computing architectures, a suite of "miniapps" has been created to serve as proxies for full scale applications. Each miniapp is designed to represent a key performance characteristic that does or is expected to significantly impact the runtime performance of an application program. In this paper we introduce a methodology for assessing the ability of these miniapps to effectively represent these performance issues. We applied this methodology to three miniapps, examining the linkage between them and an application they are intended to represent. Herein we evaluate the fidelity of that linkage. This work represents the initial steps required to begin to answer the question, "Under what conditions does a miniapp represent a key performance characteristic in a full app?"

Wilke, Jeremiah J.; Bettencourt, Matthew T.; Bova, S.W.; franko, ken f.; Gamell, Marc G.; Grant, Ryan E.; Hammond, Simon D.; Hollman, David S.; Knight, Samuel K.; Kolla, Hemanth K.; Lin, Paul L.; Olivier, Stephen L.; Sjaardema, Gregory D.; Slattengren, Nicole S.; Teranishi, Keita T.; Bennett, Janine C.; Clay, Robert L.

Abstract not provided.

Bennett, Janine C.; Wilke, Jeremiah J.; Slattengren, Nicole S.; Teranishi, Keita T.; Lin, Paul L.; Sjaardema, Gregory D.; Kolla, Hemanth K.

Abstract not provided.

Bennett, Janine C.; Wilke, Jeremiah J.; Slattengren, Nicole S.; Teranishi, Keita T.; Lin, Paul L.; Sjaardema, Gregory D.; Kolla, Hemanth K.; Hollman, David S.; Knight, Samuel K.; franko, ken f.; Clay, Robert L.

Abstract not provided.