Doctoral Retreat 2015 HPC Software: Synthesis, Analysis, and - PowerPoint PPT Presentation

Doctoral Retreat 2015 HPC Software: Synthesis, Analysis, and Optimization Hosting Projects: ExaStencils + FFMK Location: Universität Passau 14-18 September 2015 SPPEXA Doctoral Retreat 2015, Universität Passau, Christian Lengauer

Tw o Alternative Approaches in SPPEXA The evolutionary approach:  Fortran MPI + ) ++ ( C OpenMP Java Threads The revolutionary approach:  HPC cluster linear transformations linear algebra domain-specific Manycores stencil codes refinement and . optimization GPGPUs . . FPGAs SPPEXA Doctoral Retreat 2015, Universität Passau, Christian Lengauer

What Makes a Domain Suitable for the Revolutionary Approach? Size  Considerably smaller than by contemporary expectations  Theoretical basis  Algebra  Conditional equations  Significance  Stable abstract view  Stable, sustained user community  Examples  FFTW: the fastest Fourier transform in the West  Spiral: discrete linear transforms  DBMSs: relational query optimization  cpp: Linux operating system configuration  ExaStencils: Multigrid stencil codes  SPPEXA Doctoral Retreat 2015, Universität Passau, Christian Lengauer

Our Project in the Revolutionary Tier of SPPEXA http://www.exastencils.org/ A tool-assisted, fully automated domain-specific design approach for stencil codes Jürgen Teich, Ulrich Rüde, Matthias Bolten, Christian Lengauer, Sven Apel, Frank Hannig, Harald Köstler, Hannah Rittich Armin Größlinger, Alexander Grebhahn Christian Schmitt Sebastian Kuckuk Stefan Kronawitter SPPEXA Doctoral Retreat 2015, Universität Passau, Christian Lengauer 4

Work Areas of ExaStencils A: Algorithm design B: Domain-specific representation und modeling C: Domain-specific optimization and generation D: Polyhedral optimization and code generation E: Platform-specific code optimization and generation SPPEXA Doctoral Retreat 2015, Universität Passau, Christian Lengauer

Work Areas of ExaStencils A: Algorithm design B: Domain-specific representation and modeling C: Domain-specific optimization and generation D: Polyhedral optimization and code generation E: Platform-specific code optimization and generation Present scope: • scalar elliptic PDEs • cuboid domains • equispaced grids Future scope: • more complex classes of PDEs and suitable discretizations This week: Analysis of PDE solvers SPPEXA Doctoral Retreat 2015, Universität Passau, Christian Lengauer

Work Areas of ExaStencils A: Algorithm design B: Domain-specific representation and modeling C: Domain-specific optimization and generation D: Polyhedral optimization and code generation E: Platform-specific code optimization and generation • Domain-specific language ExaSlang • Target-Platform Description Language This week: Domain-specific programming with Julia SPPEXA Doctoral Retreat 2015, Universität Passau, Christian Lengauer

Work Areas of ExaStencils A: Algorithm design B: Domain-specific representation and modeling C: Domain-specific optimization and generation D: Polyhedral optimization and code generation E: Platform-specific code optimization and generation Empirical prediction of well- performing configurations This week: Software product lines SPPEXA Doctoral Retreat 2015, Universität Passau, Christian Lengauer

Work Areas of ExaStencils A: Algorithm design B: Domain-specific representation and modeling C: Domain-specific optimization and generation D: Polyhedral optimization and code generation E: Platform-specific code optimization and generation Polyhedral optimization steps:  model extraction  dependence computation  dead-code elimination  schedule optimization  tiling  abstract syntax tree creation This week: The polyhedron model for loop parallelization SPPEXA Doctoral Retreat 2015, Universität Passau, Christian Lengauer

Work Areas in ExaStencils A: Algorithm design B: Domain-specific representation and modeling C: Domain-specific optimization and generation D: Polyhedral optimization and code generation E: Platform-specific code optimization and generation Mean Time per V-Cycle 700 600 500 Mean Time [ms] This week: 400 Score-P and 300 200 Vampir 100 0 512 1k 2k 4k 8k 16k 32k 64k 128k 256k 448k Number of Cores Pure MPI 32 MPI x 2 OMP 16 MPI x 4 OMP 8 MPI x 8 OMP 4 MPI x 16 OMP 2 MPI x 32 OMP 1 MPI x 64 OMP SPPEXA Doctoral Retreat 2015, Universität Passau, Christian Lengauer

Goal of the Retreat: Education and Technology Transfer Education  New w ays of abstraction  New w ays of customizing code for a problem domain  Model-oriented approaches  Multigrid technology  Technology Transfer  What of this material can you leverage in your project?  Is there potential for a cooperation in funding period 2?  Time for discussion on Friday afternoon! SPPEXA Doctoral Retreat 2015, Universität Passau, Christian Lengauer