1. QCD Project Overview Ying Zhang September 26, 2005

2. DOE SciDAC Program  Scientific Discovery through advanced Computing  Funded by Department of Energy, the Office of Science (SC)  http://www.scidac.org/  Goals:  Translate the computing technology advances in 21 st century into corresponding increases in the capabilities of scientific codes  Research, development and deployment of software to accelerate the development of scientific codes and to achieve maximum efficiency on high-end computers  Research on network technologies and software to link researchers and to facilitate movement of large data sets

3. DOE SciDAC Program Source: SciDAC web site

4. DOE SciDAC Program  Several programs under SciDAC  Under Advanced Scientific Computing (MICS)  High-End Computer System Performance: PERC  And others…  Under High Energy Nuclear Physics (HENP)  National Infrastructure for Lattice Gauge Computing (Lattice QCD)  And others…  Several others on Biology, Fusion Energy, Basic Energy, …

5. SciDAC Lattice QCD  Involves most U.S. lattice theorists  funding primarily for software, but also clusters  integration of disparate activities  software structure for code/data interoperability  Two, complementary hardware approaches  commodity clusters at FermiLab and Jefferson Lab  QCDOC hardware at Columbia/Brookhaven  Software  QMP, communication library optimized for QCD Myrinet GM, QCDOC mesh and MPI  QLA, lattice-aware single node linear algebra  QDP, lattice wide data parallel computations  QIO, parallel file I/O  optimized inverters

6. Lattice QCD  Quantum Chromodynamics (QCD)  strong interaction between quarks, mediated by gluons  Both nuclear physicists and high-energy physicists are involoved  PI: Bob Sugar at UCSB  Lattice QCD  numerical simulation of QCD via discretized space/time quarks at lattice points, with gluons mediating along edges –SU(3) matrix operations dominate the calculation  yields complex, sparse matrices solution via conjugate gradient techniques  MILC (MIMD Lattice Computation)  one lattice QCD implementation  http://www.usqcd.org/

7. Lattice QCD Source: Richard C. Brower & Robert Edwards

8. Optimized Dirac Operators, Inverters Level 3 QDP (QCD Data Parallel) Lattice Wide Operations, Data shifts Level 2 QMP (QCD Message Passing) QLA (QCD Linear Algebra) Level 1 QIO XML I/O DIME Lattice QCD Software Plans C/C++ implementation supports MPI, GM, QCDOC and gigabit Ethernet C/C++ implementation Optimized for Pentium 4 and QCDOC Source: Richard C. Brower & Robert Edwards

9. Current Work  Application benchmarking  MILC and Chroma(C++) codes  Opteron, Intel, Power, SGI, BG/L, QCDOC, Cray, …  10-100/GigE/10-GigE Ethernet, Quadrics, Myrinet, Infiniband  Bottleneck and scalability analysis  processor count, cache size, and lattice size  Total cost of ownership  power-performance products and scaling  Multiversion code selection  CG configuration and tuning  Performance optimization  Performance profiling library development