DragonFly On-Line Manual Pages

LIBOPENCL(7)                                                      LIBOPENCL(7)

NAME
       libOpenCL, libOpenCL.so - OCL-ICD implementation of OpenCL ICD loader

DESCRIPTION
       libOpenCL.so is the library linked by OpenCL programs. It does not
       contains any OpenCL implementation itself, but merly act as a
       dispatcher to real OpenCL implementations provided as OpenCL
       Installable Client Driver (ICD). An ICD loader should be able to load
       ICDs provided by any vendors.

       According to OpenCL specifications from Khronos (see [Khronos]), the
       ICD Loader looks for files into /usr/local/etc/OpenCL/vendors/
       directory and, for each file whose name ends with .icd, the ICD Loader
       loads with dlopen(3) the shared library whose name is on the first line
       of the .icd file.

       Shared library name in ".icd" files can have its path, or it can be a
       plain filename. In the latter case, the ICD shared library will be look
       for into the standard dynamic loader paths.

ENVIRONMENT
       Some environment variables can be used modify the default behavior of
       libOpenCL.

       OCL_ICD_VENDORS
           This variable allows one to change the way ICD are searched on the
           system. Several cases are considered:

            1. if $OCL_ICD_VENDORS is a directory path, then this path
               replaces the "/usr/local/etc/OpenCL/vendors" path in the
               standard behavior: the loader will use the .icd files in this
               directory;

            2. else, if $OCL_ICD_VENDORS ends with .icd, libOpenCL.so will
               only load the ICD whose shared library name is wrote into the
               specified ".icd" file;

               If there is no slash into $OCL_ICD_VENDORS, libOpenCL.so will
               first try to use
               /usr/local/etc/OpenCL/vendors/$OCL_ICD_VENDORS. If this fail,
               it uses $OCL_ICD_VENDORS (as a relative or absolute file name
               path).

            3. else libOpenCL.so will try to load $OCL_ICD_VENDORS as the ICD
               shared library itself (i.e. to load it directly with
               dlopen(3)).

       OCL_ICD_ASSUME_ICD_EXTENSION
           If set, contrary the Khronos specification, the loader will not
           check that the loaded ICDs declare the cl_khr_icd extension. You
           may need to define this environment variable if you are using the
           Intel ICD together with optirun(1). Else, a bug into the Intel ICD
           will make the application crash.

       OCL_ICD_PLATFORM_SORT
           Allows to choose the way platforms are sorted when presented to
           programs through clGetPlatformIDs(3). Current provided algorithms
           are:

           o    devices: first, list platforms that support most GPU, then
               most CPU then most accelerators. If OCL_ICD_PLATFORM_SORT is
               not set or set to an unknown value, this algorithm is used.

           o    none: no sort is done and the order can very at each run.

       OCL_ICD_DEFAULT_PLATFORM
           Number of the platform to choose as defaut platform. Note that
           using this environment variable without specifying a sort algorithm
           for platforms is not really useful.

       OCL_ICD_DEBUG
           If ocl-icd has been compiled with debug support, you can set this
           environment variable to a value where each bit display some kind of
           informations. Defined values are:

           o    1: warnings (enabled by default if debug support is present
               and OCL_ICD_DEBUG is not set)

           o    2: informative messages

           o    4: entering/exiting for some OpenCL functions

           o    8: dump of the internal structure of loaded ICDs

           OCL_ICD_DEBUG is mainly useful for ocl-icd development itself
           and/or for ICD development.

SEE ALSO
       Khronos OpenCL registry website

AUTHOR
       Vincent Danjean <Vincent.Danjean@ens-lyon.org>
           Author.

                                  10/06/2015                      LIBOPENCL(7)