J.J. KeijserNikhefAmsterdamGrid Group

GPU Computing

Jan Just KeijserNikhef Jamboree, Utrecht10 December 2012

J.J. KeijserNikhefAmsterdamGrid Group

What is a GPU?

J.J. KeijserNikhefAmsterdamGrid Group

J.J. KeijserNikhefAmsterdamGrid Group

GPUs are excellent for performing the Same operation (Instruction) on

Multiple Data elements (SIMD)Vector processing, anyone?

What can you do with a GPU?

From: Massively Parallel Computing with CUDA

J.J. KeijserNikhefAmsterdamGrid Group

How do you program a GPU?

From: An Introduction to GPU Computing and CUDA Architecture

J.J. KeijserNikhefAmsterdamGrid Group

How do you program a GPU?

From: An Introduction to GPU Computing and CUDA Architecture

J.J. KeijserNikhefAmsterdamGrid Group

How do you program a GPU?

From: An Introduction to GPU Computing and CUDA Architecture

J.J. KeijserNikhefAmsterdamGrid Group

Programming languagesNVIDIA CUDAAMD/ATI Stream ComputingOpen standard: OpenCL

◦ Supported by NVIDIA, AMD, Intel, ARM

Language bindingsC/C++FORTRANPython, PerlR, MATLAB, Mathematica

J.J. KeijserNikhefAmsterdamGrid Group

Possible applicationsFluid dynamicsTomographyMonte Carlo simulationsChroma Library for Lattice Field Theory ... ?

At Nikhef:ANTARES/KM3NETVIRGO ... ?

J.J. KeijserNikhefAmsterdamGrid Group

No silver bulletRequires code

rewrite and optimization

GPU architectures rapidly change, so do the optimization techniques

Limited by amount of memory on the GPU card (≤ 8 GB)

Number of cores on a CPU is also rapidly increasing

J.J. KeijserNikhefAmsterdamGrid Group

Available GPUs @ NikhefSome desktops already have a GPU!

◦ NVIDIA Quadro NVS290 (low end)◦ AMD Firepro V5900

1 server with 2 x NVIDIA Tesla M2070

Q2 2013: Intel Xeon Phi testboard

Elsewhere in the Netherlands:SARA: GPU cluster (Tesla C1070)RuG: GPU cluster Successor to Huygens will use GPUsLeiden: Little Green Machine

J.J. KeijserNikhefAmsterdamGrid Group