StarPU: A Unified Runtime System for Heterogeneous Multicore Architectures

What is StarPU?

StarPU is a runtime system that offers support for heterogeneous multicore machines. While many efforts are devoted to design efficient computation kernels for those architectures (e.g. to implement BLAS kernels on GPUs), StarPU not only takes care of offloading such kernels (and implementing data coherency across the machine), but it also makes sure the kernels are executed as efficiently as possible.

What StarPU is not

StarPU is not a new language, and it does not extend existing languages either. StarPU does not help to write computation kernels.

(How) Could StarPU help me?

While StarPU will not make it easier to write computation kernels, it does simplify their actual offloading as StarPU handle most low level aspects transparently.

Obviously, it is crucial to have efficient kernels, but it must be noted that the way those kernels are mapped and scheduled onto the computational resources also affect the overall performance to a great extent.

StarPU is especially helpful when considering multiple heterogeneous processing resources: statically mapping and synchronizing tasks in such a heterogeneous environment is already very difficult, making it in a portable way is virtually impossible. On the other hand, the scheduling capabilities of StarPU makes it possible to easily exploit all processors at the same time while taking advantage of their specificities in a portable fashion.

Requirements

• make
• gcc (version >= 4.1)
• if CUDA support is enabled
  • CUDA (version >= 2.2)
  • CUBLAS (version >= 2.2)
• if OpenCL support is enabled
  • AMD SDK >= 2.3 if AMD driver is used
  • CUDA >= 3.2 if NVIDIA driver is used
• extra requirements for the git version (we usually use the Debian testing versions)
  • autoconf (version >= 2.60)
  • automake
  • makeinfo
  • libtool (version >= 2)

Remark: It is strongly recommended that you also install the hwloc library before installing StarPU. This permits StarPU to actually map the processing units according to the machine topology. For more details on hwloc, see http://www.open-mpi.org/projects/hwloc/ .

Getting StarPU

StarPU is available on https://gitlab.inria.fr/starpu/starpu

The GIT repository access can be checked out with the following command.

$ git clone https://gitlab.inria.fr/starpu/starpu.git

Building and Installing

For git version only

Please skip this step if you are building from a tarball.

$ ./autogen.sh

For all versions

$ mkdir build && cd build
$ ../configure
$ make
$ make install

Windows build

StarPU can be built using MinGW or Cygwin. To avoid the cygwin dependency, we provide MinGW-built binaries. The build process produces libstarpu.dll, libstarpu.def, and libstarpu.lib, which should be enough to use it from e.g. Microsoft Visual Studio.

Update the video drivers to the latest stable release available for your hardware. Old ATI drivers (< 2.3) contain bugs that cause OpenCL support in StarPU to hang or exhibit incorrect behaviour.

For details on the Windows build process, see the INSTALL file.

Running StarPU Applications on Microsoft Visual C

Batch files are provided to run StarPU applications under Microsoft Visual C. They are installed in path_to_starpu/bin/msvc.

To execute a StarPU application, you first need to set the environment variable STARPU_PATH.

c:\....> cd c:\cygwin\home\ci\starpu\
c:\....> set STARPU_PATH=c:\cygwin\home\ci\starpu\
c:\....> cd bin\msvc
c:\....> starpu_open.bat starpu_simple.c

The batch script will run Microsoft Visual C with a basic project file to run the given application.

The batch script starpu_clean.bat can be used to delete all compilation generated files.

The batch script starpu_exec.bat can be used to compile and execute a StarPU application from the command prompt.

c:\....> cd c:\cygwin\home\ci\starpu\
c:\....> set STARPU_PATH=c:\cygwin\home\ci\starpu\
c:\....> cd bin\msvc
c:\....> starpu_exec.bat ..\..\..\..\examples\basic_examples\hello_world.c

MSVC StarPU Execution
...
/out:hello_world.exe
...
Hello world (params = {1, 2.00000})
Callback function got argument 0000042
c:\....>

Documentation

Doxygen documentation is available in doc/doxygen. If the doxygen tools are available on the machine, pdf and html documentation can be generated by running

$ make -C doc

The documentation for the latest StarPU release is available, as well as the documentation for the StarPU master branch.

Trying

Some examples ready to run are installed into $prefix/lib/starpu/{examples,mpi}

Upgrade

To upgrade your source code from older version (there were quite a few renamings), use the tools/dev/rename.sh script.

Contribute

Contributions are welcome! Both on the main StarPU repository and on the github StarPU mirror

Please see our contribution page for details.

Contact

For any questions regarding StarPU, please contact the starpu-devel mailing-list at [email protected] or browse the StarPU website.