L21: Parallel Programming Language Features

1. L21: Parallel Programming Language Features November 24, 2009

2. Administrative • Schedule for the rest of the semester • “Midterm Quiz” = long homework • Handed out over the holiday (Tuesday, Dec. 1) • Return by Dec. 15 • Projects • 1 page status report on Dec. 3 • Poster session dry run (to see material) Dec. 8 • Mailing list: cs4961@list.eng.utah.edu

3. Outline • SC09 Trip Report • Large (> 11000 people) conference and trade show on High Performance Computation and Communication • Evaluating Parallel Programming Languages • Global View Languages • Chapel Programming Language • Reading: Ch. 8 and 9 in textbook

4. Recall from Lecture 1: The fastest computer in the world today RoadRunner Los Alamos National Laboratory ~19,000 processor chips (~129,600 “processors”) AMD Opterons and IBM Cell/BE (in Playstations) 1.105 Petaflop/second One quadrilion operations/s 1 x 1016 • What is its name? • Where is it located? • How many processors does it have? • What kind of processors? • How fast is it? See http://www.top500.org CS4961

5. The SECOND fastest computer in the world today RoadRunner Los Alamos National Laboratory ~19,000 processor chips (~129,600 “processors”) AMD Opterons and IBM Cell/BE (in Playstations) 1.105 Petaflop/second One quadrilion operations/s 1 x 1016 • What is its name? • Where is it located? • How many processors does it have? • What kind of processors? • How fast is it? See http://www.top500.org CS4961

6. The fastest computer in the world today Jaguar (Cray XT5) Oak Ridge National Laboratory ~37,000 processor chips (224,162 cores) AMD 6-core Opterons 1.759 Petaflop/second One quadrilion operations/s 1 x 1016 • What is its name? • Where is it located? • How many processors does it have? • What kind of processors? • How fast is it? See http://www.top500.org CS4961

7. Keynote: Justin Rattner, Intel CTO • Topic: 3D Internet • Key Idea: • Second Life, and the like represent the 3D Internet • Lots and lots of computation (a purpose for multi-cores in the home environment!) • Focus of talk was on animating cloth • Most Exciting Moment: • Intel Larrabee prototype running sgemm at 1Tflop!

8. Keynote: Al Gore, Former Vice President and Winner of Nobel Prize and Oscar  • Topic: Climate Change and Scientific Leadership • Best Moments • Lots of good jokes! • Integrated a 30-minute briefing from the conference committee into his presentation • Call to Action: • Get rid of combustion engines, more wind and solar power, … • Engaging the scientific community • Engaging the young people to share his passion and get involved

9. Major ACM and IEEE-CS Awards Presented • ACM IEEE-CS Ken Kennedy Award • Recognizes contributions in programmability and productivity of computing systems and mentoring and service Winner: Fran Berman, Vice President for Research, RPI Laying the Groundwork for Success in the Information Age • IEEE-CS Seymour Cray Award • Recognizes innovations in computer architectures for HPC Winner: Ken Miura, Fellow of Fujitsu Laboratories Limited My Adventures in Parallel Computing • IEEE-CS Sidney Fernbach Award • Recognizes application of HPC to solve large-scale problem • Roberto Car (Princeton) and Michele Parrinello (ETH) Molecular-scale modeling: the challenge of quantum simulations Challenges and progress in atomistic simulations

10. Gordon Bell Prize • Recognizes Best Performance on a Real Application • Unlike Top500 • Winner in the Peak Performance Category: A Scalable Method for Ab Initio Computation of Free Energies in Nanoscale Systems Markus Eisenbach, Donald M. Nicholson (Oak Ridge National Laboratory), Chenggang Zhou (J.P. Morgan Chase & Co), Gregory Brown (Florida State University), Jeff Larkin (Cray Inc), and Thomas C. Schulthess (ETH Zurich)

11. Best Paper Millisecond-Scale Molecular Dynamics Simulations on Anton David E. Shaw, Ron O. Dror, John K. Salmon, J.P. Grossman, Kenneth M. Mackenzie, Joseph A. Bank, Cliff Young, Martin M. Deneroff, Brannon Batson, Kevin J. Bowers, Edmond Chow, Michael P. Eastwood, Douglas J. Ierardi, John L. Klepeis, Jeffrey S. Kuskin, Richard H. Larson, Kresten Lindorff-Larsen, Paul Maragakis, Mark A. Moraes, Stefano Piana, Yibing Shan, and Brian Towles (D.E. Shaw Research)

12. Shifting Gears And what about ease of programming? • What are some important features of parallel programming languages (Ch. 9)? • Correctness • Performance • Scalability • Portability

13. Global View Versus Local View • P-Independence • If and only if a program always produces the same output on the same input regardless of number or arrangement of processors • Global view • A language construct that preserves P-independence • Example (today’s lecture) • Local view • Does not preserve P-independent program behavior • Example from previous lecture?

14. What is a PGAS Language? • PGAS = Partitioned Global Address Space • Present a global address space to the application developer • May still run on a distributed memory architecture • Examples: Co-Array Fortran, Unified Parallel C • Modern parallel programming languages present a global address space abstraction • Performance? Portability? • A closer look at a NEW global view language, Chapel • From DARPA High Productivity Computing Systems program • Language design initiated around 2003 • Also X10 (IBM) and Fortress (Sun)