Kokkos Tutorials

This repository contains tutorials for the Kokkos C++ programming model (github.com/kokkos/kokkos).

The Kokkos Lectures

We are currently running The Kokkos Lectures - an extended version of our Intro-Full Tutorial, spanning 8 modules. For information on that, Slides and Recordings visit: The Kokkos Lectures Wiki

Other Tutorial Compilations

Tutorials in the Intro-Short directory cover

• simple data parallel patterns and policies
• multidimensional array views
• execution and memory spaces

Tutorials in the Intro-Full directory cover

• simple data parallel patterns and policies
• multidimensional array views
• execution and memory spaces
• thread safety and atomic operations
• hierarchical data parallel patterns

Building the Tutorials

All the tutorial folders can be built using either the Makefile or the CMake CMakeLists.txt file in each folder.

Makefiles

The raw Makefiles require Makefile variables to be properly configured. In most examples, this is KOKKOS_PATH pointing to the Kokkos source directory and KOKKOS_DEVICES which contains the list of device backends to build. This will build a new Kokkos library for each exercise.

If you are on a system compatible to our AWS instances, you can type

make
make test

in the Exercises directory.

Compatible means:

• X86 with a NVIDIA V100 GPU
• kokkos was cloned to ${HOME}/Kokkos/kokkos

CMake + Spack

The CMake files build against an installed Kokkos library. The easiest way to do this is using Spack. There is a spack.sh script that automates most of this. The Spack script can be run in any excercise folder with a CMakeLists.txt.

../../BuildScripts/spack.sh +openmp %gcc@7.3.0

This will make sure Kokkos is installed with the OpenMP backend for the GCC 7.3.0 compiler. It will then configure CMake and create a spack-build folder where make can be run. The spack.sh accepts the full list of variants and specs as the parent Kokkos package, which can be viewed by running:

spack info kokkos

The spack.sh script uses the special DIY mode of Spack to install dependencies and configure the current source folder to build.

For Kokkos Kernels tutorials, there is similarly a kk-spack.sh script, e.g.

../../BuildScripts/kk-spack.sh +openmp %gcc@7.3.0 ^kokkos+aggressive_vectorization

All the arguments to the script get passed as a spec for the tutorial. We are indirectly configuring Kokkos, hence the ^ notation for specifying the exact Kokkos dependency spec.