UPC at LBNL/U.C. Berkeley Overview

1
UPC at LBNL/U.C. BerkeleyOverview

• Kathy Yelick
• U.C. Berkeley, EECS
• LBNL, Future Technologies Group

2
Unified Parallel C (UPC) at LBNL/UCB

• Unified Parallel C is a parallel language
  designed to
• Make parallel machines more accessible to users
• Enable better efficiency and scalability than
  other models
• Based on research languages from Berkeley, DoD,
  and DOE labs
• UPC has broad support
• UPC compilers available on Cray, SGI, and HP
  machines
• Over 100 attendees at the last UPC meeting
• The Berkeley UPC Compiler is a joint LBNL/UCB
  effort
• Lead by Kathy Yelick, with 4 LBNL staff, 2 UCB
  students, and 2 both
• About 1M in annual funding (through the DOE
  Programming Models Center, DOE base program
  funding, and DoD funding)
• Goals
• Enable wide-spread use of UPC by providing a
  portable open source compiler for UPC
  (gcc-like)
• Identify and demonstrate optimizations for this
  class of languages, which are relatively
  unstudied in the compiler community

3
Berkeley UPC Compiler Results

• First release scheduled for this month, March 03
• Based on Open64 open source C and Fortran
  compiler
• Generates C as portable assembly language and
  one-sided communication a layer called GASNet,
  developed by the group
• Tuned networking layers for Myrinet, IBM-SP, and
  Quadrics, with reference implementation for MPI
• Initial benchmarks show
• In spite of portability constraints, such as
  generating C, the Berkeley compiler often beats
  the HP compiler on HP hardware!
• Performance is comparable to MPI on the NAS
  Parallel Benchmarks (within a few percent)
• Several optimization opportunities exist