Ramprasad Venkataraman
Staff
ramv at illinois.edu
Profile

I am a research staff member at the lab, where my work focuses on evolving and scaling the core components of the Charm++ runtime system as well as helping Charm++ applications parallelize and scale their algorithms.

I've worked on several aspects of the programming framework and adaptive runtime system, and have a good understanding of how to build and scale runtime components for managed, distributed parallelism. I've also worked on scaling parallel applications here at PPL; and at the Computational Simulation Lab and the Section on Statistical Genetics, both at the University of Alabama at Birmingham.

Interests

My interests lie at the confluence of scalable algorithms for application domains, programming models for expressing these parallel algorithms, runtime systems for managing the parallelism, and extracting performance at extreme scale. There are several research questions in each of these, and I hope to find and express some of the answers in a useful form by building massively parallel software systems.

I strongly believe that managed parallelism is key to performance. Parallel programs should just express domain logic with annotations that permit other software components to manage execution and extract performance. This has already been demonstrated by several successful parallel programming frameworks in industry and research. Such managed parallelism becomes possible when algorithms express only the dependencies and minimum requirements of when a computation can execute, instead of dictating when a computation should execute. This approach, coupled with the expression of more parallelism than available hardware concurrency (overdecomposition), permits high performance.

The general-purpose, Charm++ programming model embodies many of these principles: overdecomposed, migratable objects, driven by asynchronous methods, and orchestrated by a runtime system that observes and adapts for better performance.

Application Domain Experience
Here are some of the things I've spent time developing/optimizing software for:
  • Quantum chemistry
  • Stochastic optimization for resource allocation
  • Parallel, dense, linear algebra
  • Bayesian methods for gene-trait mapping
  • Haplotype reconstruction from genetic data
  • Atomistic, rarefied gas dynamics
  • Continuum fluid dynamics
  • Equilibrium and finite-rate combustion chemistry
  • Hybrid continuum-atomistic fluid flows
Publications and Talks outside PPL
2008
[Thesis]
Enabling the Direct Simulation (Monte Carlo) of Physical Vapor Deposition [Thesis 2008]
Ramprasad Venkataraman
Master's Thesis, Dept. of Mechanical Engineering, University of Alabama at Birmingham
2007
[Paper]
R/qtlbim: QTL with Bayesian Interval Mapping in experimental crosses [Bioinformatics 2007]
Yandell BS, Mehta T, Banerjee S, Shriner D, Venkataraman R, Moon JY, Neely WW, Wu H, Smith R, Yi N;
Bioinformatics 23(5):641-643, 2007
2005
[Talk]
Direct Simulation Monte Carlo: From Atmospheric Re-entry to Thin Film Deposition [GSRD 2005]
Ramprasad Venkataraman
Graduate Student Research Day, University of Alabama at Birmingham
2004
[Paper]
Towards a Hybrid DSMC/Navier-Stokes Method for High Speed Re-entry Flow Simulations[HSC 2004]
Ramprasad Venkataraman, Y.Y.Lian, J.S.Wu, Gary Cheng, Roy P. Koomullil;
Huntsville Simulation Conference, Oct 2004
2004
[Paper]
Three Dimensional Parallel DSMC Method for High-Speed Re-entry Flow Simulation[SECTAM 2004]
Ramprasad Venkataraman, Y.Y.Lian, J.S.Wu, Gary Cheng, Roy P. Koomullil;
Developments in Theoretical and Applied Mechanics; Proceedings of the 22nd SECTAM; Vol XXII; 125:137; Aug 2004
Research Areas
Papers
13-42
2013
[Paper]
Parallel Science and Engineering Applications: The Charm++ Approach: Chapter 5: OpenAtom: Ab-initio Molecular Dynamics for Petascale Platforms [Book 2013]
13-29
2013
[Paper]
Parallel Branch-and-Bound for Two-Stage Stochastic Integer Optimization [HiPC 2013]
13-08
2013
[Paper]
In Search of a Scalable, Parallel Branch-and-Bound for Two-Stage Stochastic Integer Optimization [PPL Technical Report 2013]
12-47
2012
[Paper]
Migratable Objects + Active Messages + Adaptive Runtime = Productivity + Performance: A Submission to the 2012 HPC Class II Challenge [SC 2012]
12-36
2012
[Paper]
Performance Optimization of a Parallel, Two Stage Stochastic Linear Program: The Military Aircraft Allocation Problem [ICPADS 2012]
| Akhil Langer | Ramprasad Venkataraman | Udatta Palekar | Laxmikant Kale | Steven Baker
12-22
2012
[Paper]
Scalable Algorithms for Constructing Balanced Spanning Trees on System-ranked Process Groups [EuroMPI 2012]
12-07
2012
[Paper]
Parallel Computing for DoD Airlift Allocation [PPL Technical Report 2012]
| Steven Baker | Udatta Palekar | Gagan Gupta | Laxmikant Kale | Akhil Langer | Mark Surina | Ramprasad Venkataraman
11-51
2012
[Paper]
Mapping Dense LU Factorization on Multicore Supercomputer Nodes [IPDPS 2012]
11-49
2011
[Paper]
Charm++ for Productivity and Performance: A Submission to the 2011 HPC Class II Challenge [SC 2011]
11-34
2011
[Paper]
Exploring Partial Synchrony in an Asynchronous Environment Using Dense LU [PPL Technical Report 2011]
09-30
2009
[Paper]
Patterns for Overlapping Communication and Computation [ParaPLoP 2009]
Talks/Posters
13-57
2013
[Talk]
Parallel Branch-and-Bound for Two-stage Stochastic Integer Optimization [HiPC 2013]
13-03
2013
[Poster]
Charm++: Migratable Objects + Active Messages + Adaptive Runtime = Productivity + Performance [PSAAP Site-visit 2013]
12-49
2012
[Talk]
Performance Optimization of a Parallel, Two Stage Stochastic Linear Program: The Military Aircraft Allocation Problem [ICPADS 2012]
| Akhil Langer | Ramprasad Venkataraman | Udatta Palekar | Laxmikant Kale | Steven Baker
12-40
2012
[Talk]
Scalable Algorithms for Constructing Balanced Spanning Trees on System-ranked Process Groups [EuroMPI 2012]
12-23
2012
[Talk]
Mapping Dense LU Factorization on Multicore Supercomputer Nodes [IPDPS 2012]
11-33
2011
[Poster]
Enabling Massive Parallelism for Stochastic Optimization [SC 2011]
| Akhil Langer | Ramprasad Venkataraman | Gagan Gupta | Laxmikant Kale | Udatta Palekar | Steven Baker | Mark Surina