NERSCPowering Scientific Discovery Since 1974

Christopher Daley

Christopher Steven Daley
HPC Performance Engineer
Advanced Technology Group
Phone: (510) 486-4504
Fax: (510) 486-6459
National Energy Research Scientific Computing Center
1 Cyclotron Rd
Mailstop: 59R4010A (office 59-3072B)
Berkeley, California 94720 US

Biographical Sketch

Chris Daley is a member of the Advanced Technology Group (ATG).  Before joining ATG, Chris was a Scientific Programmer at the Flash Center for Computational Science at the University of Chicago.  He has a M.Sc. in High Performance Computing from the University of Edinburgh and a B.Sc. in Physics from the University of Surrey.

Journal Articles

J. Park, M. Smelyanskiy, K. Vaidyanathan, A. Heinecke, D Kalamkar, M Patwary, V. Pirogov, P. Dubey, X. Liu, C. Rosales, C. Mazauric, C. Daley, "Optimizations in a high-performance conjugate gradient benchmark for IA-based multi- and many-core processors", International Journal of High Performance Computing Applications, 2015, doi: 10.1177/1094342015593157

Jack Deslippe, Brian Austin, Chris Daley, Woo-Sun Yang, "Lessons learned from optimizing science kernels for Intel's "Knights-Corner" architecture", CISE, April 1, 2015,

A. Dubey, K. Antypas, A. C. Calder, C. Daley, B. Fryxell, J. B. Gallagher, D. Q. Lamb, D. Lee, K. Olson, L. B. Reid, P. Rich, P. M. Ricker, K. M. Riley, R. Rosner, A. Siegel, N. T. Taylor, K. Weide, F. X. Timmes, N. Vladimirova, and J. ZuHone, "Evolution of FLASH, a multi-physics scientific simulation code for high-performance computing", International Journal of High Performance Computing Applications, May 2014, doi: 10.1177/1094342013505656

A. Dubey, K. Weide, D. Lee, J. Bachan, C. Daley, S. Olofin, N. Taylor, P. M. Rich, and L. B. Reid, "Ongoing verification of a multiphysics community code: FLASH", Software: Practice and Experience, September 2013, doi: 10.1002/spe.2220

A. Dubey, A. Calder, C. Daley, C., R. Fisher, Jordan, D.Q. Lamb, L.B. Reid, D.M. Townsley, K. Weide, "Pragmatic Optimizations for Best Scientific Utilization of Large Supercomputers", International Journal of High Performance Computing Applications, July 2013, doi: 10.1177/1094342012464404

A. Dubey, C. Daley, J. ZuHone, P. M. Ricker, K. Weide, C. Graziani, "Imposing a Lagrangian Particle Framework on an Eulerian Hydrodynamics Infrastructure in FLASH", The Astrophysical Journal Supplements, 2012, 201:27, doi: 10.1088/0067-0049/201/2/27

C. Daley, M. Vanella, K. Weide, A. Dubey, E. Balaras, "Optimization of Multigrid Based Elliptic Solver for Large Scale Simulations the FLASH Code", Concurrency and Computation: Practice and Experience, 2012, 24:2346--2361, doi: 10.1002/cpe.2821

R. Latham, C. Daley, W.K. Liao, K. Gao, R. Ross, A. Dubey, A. Choudhary, "A case study for scientific I/O: improving the FLASH astrophysics code", Computational Science and Discovery, 2012, 5:015001, doi: 10.1088/1749-4699/5/1/015002

D. Lee, G. Xia, C. Daley, A. Dubey, S., C. Graziani, D.Q. Lamb, K. Weide, "Progress in development of HEDP capabilities in FLASH's Unsplit Staggered Mesh MHD solver", Astrophysics and Space Science, 2011, 336:157-162, doi: 10.1007/s10509-011-0654-5

B. R. de Supinski, S. Alam, D. H. Bailey, L., C. Daley, A. Dubey, T., D. Gunter, P. D. Hovland, H., K. Karavanic, G. Marin, J., S. Moore, B. Norris, L., C. Olschanowsky, P. C. Roth, M., S. Shende, A. Snavely, Spear, M. Tikir, J. Vetter, P. Worley, N. Wright, "Modeling the Office of Science ten year facilities plan: The PERI Architecture Tiger Team", Journal of Physics: Conference Series, 2009, 180:012039,

Conference Papers

W. Bhimji, D. Bard, M. Romanus, D. Paul, A. Ovsyannikov, B. Friesen, M. Bryson, J. Correa, G. K. Lockwood, V. Tsulaia, S. Byna, S. Farrell, D. Gursoy, C. Daley, V. Beckner, B. Van Straalen, D. Trebotich, C. Tull, G. Weber, N. J. Wright, K. Antypas, Prabhat, "Accelerating Science with the NERSC Burst Buffer Early User Program", Cray User Group, May 11, 2016, LBNL LBNL-1005736,

NVRAM-based Burst Buffers are an important part of the emerging HPC storage landscape. The National Energy Research Scientific Computing Center (NERSC) at Lawrence Berkeley National Laboratory recently installed one of the first Burst Buffer systems as part of its new Cori supercomputer, collaborating with Cray on the development of the DataWarp software. NERSC has a diverse user base comprised of over 6500 users in 700 different projects spanning a wide variety of scientific computing applications. The use-cases of the Burst Buffer at NERSC are therefore also considerable and diverse. We describe here performance measurements and lessons learned from the Burst Buffer Early User Program at NERSC, which selected a number of research projects to gain early access to the Burst Buffer and exercise its capability to enable new scientific advancements. To the best of our knowledge this is the first time a Burst Buffer has been stressed at scale by diverse, real user workloads and therefore these lessons will be of considerable benefit to shaping the developing use of Burst Buffers at HPC centers.

C.S. Daley, L. Ramakrishnan, S. Dosanjh, N.J. Wright, "Analyses of Scientific Workflows for Effective Use of Future Architectures", The 6th International Workshop on Big Data Analytics: Challenges, and Opportunities (BDAC-15), 2015,

M. J. Cordery, B. Austin, H. J. Wasserman, C. S. Daley, N. J. Wright, S. D. Hammond, D. Doerfler, "Analysis of Cray XC30 Performance using Trinity-NERSC-8 benchmarks and comparison with Cray XE6 and IBM BG/Q", SC'13, November 11, 2013,

P. Mohapatra, A Dubey, C. Daley, M. Vanella, and E. Balaras, "Parallel Algorithms for Using Lagrangian Markers in Immersed Boundary Method with Adaptive Mesh Refinement in FLASH", Computer Architecture and High Performance Computing (SBAC-PAD), October 2013, doi: 10.1109/SBAC-PAD.2013.27

C. Daley, J. Bachan, S. Couch, A. Dubey, M., B. Gallagher, D. Lee, K. Weide, "Adding shared memory parallelism to FLASH for many-core architectures", TACC-Intel Highly Parallel Computing Symposium, 2012,

V. Vishwanath, M. Hereld, M. E. Papka, R. Hudson, G. Jordan, C. Daley, "In Situ Data Analytics and I/O Acceleration of FLASH simulations on leadership-class systems with GLEAN", SciDAC, Journal of Physics: Conference Series, 2011,

A. Dubey, C. Daley, K. Weide, "Challenges of Computing with FLASH on Largest HPC Platforms", AIP Conference Proceedings, 2010, 1281:1773, doi:


C. Daley, Preparing for Mira: experience with FLASH multiphysics simulations, Mira Community Conference, 2013,