starpu-max/doc/doxygen/chapters/460_socl_opencl_extensions.doxy

/*
 * This file is part of the StarPU Handbook.
 * Copyright (C) 2009--2011  Universit@'e de Bordeaux
 * Copyright (C) 2010, 2011, 2012, 2013, 2016  CNRS
 * Copyright (C) 2011, 2012 INRIA
 * See the file version.doxy for copying conditions.
 */

/*! \page SOCLOpenclExtensions SOCL OpenCL Extensions

SOCL is an OpenCL implementation based on StarPU. It gives a unified access to
every available OpenCL device: applications can now share entities such as
Events, Contexts or Command Queues between several OpenCL implementations.

In addition, command queues that are created without specifying a device provide
automatic scheduling of the submitted commands on OpenCL devices contained in
the context to which the command queue is attached.

Setting the <c>CL_QUEUE_OUT_OF_ORDER_EXEC_MODE_ENABLE</c> flag on a command
queue also allows StarPU to reorder kernels queued on the queue, otherwise they
would be serialized and several command queues would be necessary to see kernels
dispatched on the various OpenCL devices.

Note: this is still an area under development and subject to change.

When compiling StarPU, SOCL will be enabled if a valid OpenCL
implementation is found on your system. To be able to run the SOCL
test suite, the environment variable \ref SOCL_OCL_LIB_OPENCL needs to
be defined to the location of the file <c>libOpenCL.so</c> of the OCL
ICD implementation. You should for example add the following line in
your file <c>.bashrc</c>

\verbatim
export SOCL_OCL_LIB_OPENCL=/usr/lib/x86_64-linux-gnu/libOpenCL.so
\endverbatim

You can then run the test suite in the directory <c>socl/examples</c>.

\verbatim
$ make check
...
PASS: basic/basic
PASS: testmap/testmap
PASS: clinfo/clinfo
PASS: matmul/matmul
PASS: mansched/mansched
==================
All 5 tests passed
==================
\endverbatim

The environment variable \ref OCL_ICD_VENDORS has to point to the directory
where the socl.icd ICD file is installed. When compiling StarPU, the files
are in the directory <c>socl/vendors</c>. With an installed version of
StarPU, the files are installed in the directory
<c>$prefix/share/starpu/opencl/vendors</c>.

To run the tests by hand, you have to call for example,

\verbatim
$ LD_PRELOAD=$SOCL_OCL_LIB_OPENCL OCL_ICD_VENDORS=socl/vendors/ socl/examples/clinfo/clinfo
Number of platforms:	2
  Plaform Profile:	FULL_PROFILE
  Plaform Version:	OpenCL 1.1 CUDA 4.2.1
  Plaform Name:		NVIDIA CUDA
  Plaform Vendor:	NVIDIA Corporation
  Plaform Extensions:	cl_khr_byte_addressable_store cl_khr_icd cl_khr_gl_sharing cl_nv_compiler_options cl_nv_device_attribute_query cl_nv_pragma_unroll 

  Plaform Profile:	FULL_PROFILE
  Plaform Version:	OpenCL 1.0 SOCL Edition (0.1.0)
  Plaform Name:		SOCL Platform
  Plaform Vendor:	INRIA
  Plaform Extensions:	cl_khr_icd
....
$
\endverbatim

To enable the use of CPU cores via OpenCL, one can set the \ref STARPU_OPENCL_ON_CPUS
environment variable to 1 and \ref STARPU_NCPUS to 0 (to avoid using CPUs both via
the OpenCL driver and the normal CPU driver).

*/