L21: Parallel Programming Language Features November 24, 2009

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: 11/24/09

Outline SC09 Trip Report -Large (> 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 11/24/09

Recall from Lecture 1: The fastest computer in the world today What is its name? Where is it located? How many processors does it have? What kind of processors? How fast is it? RoadRunner Los Alamos National Laboratory ~19,000 processor chips (~129,600 “processors”) AMD Opterons and IBM Cell/BE (in Playstations) Petaflop/second One quadrilion operations/s 1 x See 08/25/2009CS49614

The SECOND fastest computer in the world today What is its name? Where is it located? How many processors does it have? What kind of processors? How fast is it? RoadRunner Los Alamos National Laboratory ~19,000 processor chips (~129,600 “processors”) AMD Opterons and IBM Cell/BE (in Playstations) Petaflop/second One quadrilion operations/s 1 x See 08/25/2009CS49615

The fastest computer in the world today What is its name? Where is it located? How many processors does it have? What kind of processors? How fast is it? Jaguar (Cray XT5) Oak Ridge National Laboratory ~37,000 processor chips (224,162 cores) AMD 6-core Opterons Petaflop/second One quadrilion operations/s 1 x See 08/25/2009CS49616

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! 11/24/09

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 11/24/09

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 11/24/09

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) 11/24/09

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) 11/24/09

Shifting Gears What are some important features of parallel programming languages (Ch. 9)? -Correctness -Performance -Scalability -Portability 11/24/09 And what about ease of programming?

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? 11/24/09

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 Also X10 (IBM) and Fortress (Sun) 11/24/09