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: [email protected]
11/24/09
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
11/24/09
Recall from Lecture 1: The fastest
computer in the world today
• What is its name?
RoadRunner
• Where is it located?
Los Alamos National
Laboratory
• How many processors does it have? ~19,000 processor chips
(~129,600 “processors”)
• What kind of processors?
• How fast is it?
See http://www.top500.org
08/25/2009
CS4961
AMD Opterons and
IBM Cell/BE (in Playstations)
1.105 Petaflop/second
One quadrilion operations/s
1 x 1016
4
The SECOND fastest computer in the world today
• What is its name?
RoadRunner
• Where is it located?
Los Alamos National
Laboratory
• How many processors does it have? ~19,000 processor chips
(~129,600 “processors”)
• What kind of processors?
• How fast is it?
See http://www.top500.org
08/25/2009
CS4961
AMD Opterons and
IBM Cell/BE (in Playstations)
1.105 Petaflop/second
One quadrilion operations/s
1 x 1016
5
The fastest computer in the world today
• What is its name?
Jaguar (Cray XT5)
• Where is it located?
Oak Ridge National
Laboratory
• How many processors does it have? ~37,000 processor chips
(224,162 cores)
• What kind of processors?
• How fast is it?
See http://www.top500.org
08/25/2009
CS4961
AMD 6-core Opterons
1.759 Petaflop/second
One quadrilion operations/s
1 x 1016
6
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
And what about ease of programming?
11/24/09
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 2003
- Also X10 (IBM) and Fortress (Sun)
11/24/09
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CS267: Introduction