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U.S. Department of Energy’s
Office of Science
High Performance ComputingChallenges and Opportunities
Dr. Daniel [email protected]/5/2005
Office of Science
U.S. Department of Energy
2
Why is high performance computing hard?
Amdahl’s Law (No Free Lunch) Moore’s Law (Even when you think
there’s a free lunch there isn’t) Software Complexity
Office of Science
U.S. Department of Energy
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Amdahl’s Law
The time needed to complete a task is about the same as the sum of the times required to
complete the subtasks.
T ~ Tcpu + Tcomm + Ti/o
T ~ Tmesh + Tcomp + Tinterpret
T ~ Tgrowth + Texp + Tanalysis
Office of Science
U.S. Department of Energy
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Moore’s Law
The number of transistors on an integrated circuit doubles about every 2 years.
A business principle not a law of nature!
Contributes to but not directly responsible for increases in performance!
In combination with Amdahl yields increased software complexity! Memory slower than CPU’s I/O slower than memory
Office of Science
U.S. Department of Energy
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CPU Performance
Increases in clock rate but power goes as square of frequency.
Multiple instructions per clock cycle. Memory management
Caches Pin management
Clock rate increases are expected to slow and all chips will go to 4 or more cpu’s by
2010.
Office of Science
U.S. Department of Energy
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Computer Architecture PrimerComputers are like cities!
Vector Interface
Serial Interface
CPU
Cache
Interconnection Network
Office of Science
U.S. Department of Energy
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It’s all so complicated,
maybe I’ll just go infect someone
Stop Complaining! Plague…You
won’t catch me from computer
scientists or mathematicians
I’m way more dangerous than either of you or
them!
If I get to them first there’ll be no flesh to infect!!!
What does this have to do with biology?
Office of Science
U.S. Department of Energy
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Software and Hardware Complexity
The desktop of 2010 will have 4-8 processors.
Today’s 64 processor clusters will have over 500 processors
Petascale systems may have hundreds of thousands of processors. How to divide up the work Dealing with hardware failure Managing the software Enabling science
Office of Science
U.S. Department of Energy
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How to Succeed in High Performance Computing without really dying…
Never forget Amdahl Remember Willy Sutton (Go where the
money is.) The least expensive piece of software
to develop is the one you can use from someone else.
Use wetware…Collaborate
Office of Science
U.S. Department of Energy
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SciDAC Wetware for Scientific Discovery
Computers and Networks
Integrated SoftwareInfrastructure Centers
(ISICs)
Collaboratory Tools & Middleware
Scientific Application Partnerships Collaboratory Pilot Projects
Scientific Teams
ASCR
BES,BER,FES,HEP,NP
I love Wetware!!!
