NAME

       futhark-opencl - compile Futhark to OpenCL

SYNOPSIS

       futhark opencl [options…] <program.fut>

DESCRIPTION

       futhark  opencl translates a Futhark program to C code invoking OpenCL kernels, and either
       compiles that C code with a C compiler to an executable binary program, or produces  a  .h
       and .c file that can be linked with other code. The standard Futhark optimisation pipeline
       is used.

       futhark opencl uses -lOpenCL to link (-framework OpenCL on macOS).   If  using  --library,
       you will need to do the same when linking the final binary.

       The  GPU  terminology used is derived from CUDA nomenclature (e.g.  “thread block” instead
       of “workgroup”), but OpenCL nomenclature is also supported for compatibility.

OPTIONS

       Accepts the same options as futhark-c.

ENVIRONMENT VARIABLES

       CC
          The C compiler used to compile the program.  Defaults to cc if unset.

       CFLAGS
          Space-separated list of options passed to the C compiler.  Defaults to -O  -std=c99  if
          unset.

EXECUTABLE OPTIONS

       Generated executables accept the same options as those generated by futhark-c.  For the -t
       option, The time taken to perform device setup or teardown, including writing the input or
       reading  the  result,  is  not included in the measurement. In particular, this means that
       timing starts after all kernels have been compiled and data has been copied to the  device
       buffers  but  before setting any kernel arguments. Timing stops after the kernels are done
       running, but before data has been read from the buffers or the buffers have been released.

       The following additional options are accepted.

       --build-option=OPT
              Add an additional build option to the string passed to clBuildProgram().  Refer  to
              the  OpenCL  documentation  for  which  options  are  supported.  Be careful - some
              options can easily result in invalid results.

       --default-thread-block-size=INT, --default-group-size=INT
              The default size of thread blocks that are launched. Capped to the  hardware  limit
              if necessary.

       --default-num-thread-blocks,--default-num-groups=INT
              The default number of thread blocks that are launched.

       --default-threshold=INT
              The  default parallelism threshold used for comparisons when selecting between code
              versions  generated  by  incremental  flattening.   Intuitively,  the   amount   of
              parallelism needed to saturate the GPU.

       --default-tile-size=INT
              The  default  tile  size used when performing two-dimensional tiling (the workgroup
              size will be the square of the tile size).

       -d,--device=NAME
              Use the first OpenCL device whose name contains  the  given  string.   The  special
              string  #k,  where  k  is an integer, can be used to pick the k-th device, numbered
              from zero.  If used  in  conjunction  with  -p,  only  the  devices  from  matching
              platforms are considered.

       --dump-opencl=FILE
              Don’t  run  the  program,  but  instead  dump  the  embedded  OpenCL program to the
              indicated file.  Useful if you want to see what is actually being executed.

       --dump-opencl-binary=FILE
              Don’t run the program, but instead dump the compiled version of the embedded OpenCL
              program to the indicated file.  On NVIDIA platforms, this will be PTX code.

       --load-opencl=FILE
              Instead of using the embedded OpenCL program, load it from the indicated file.

       --load-opencl-binary=FILE
              Load an OpenCL binary from the indicated file.

       -p,--platform=NAME
              Use  the  first  OpenCL platform whose name contains the given string.  The special
              string #k, where k is an integer, can be used to pick the k-th  platform,  numbered
              from zero.

       --list-devices
              List all OpenCL devices and platforms available on the system.

SEE ALSO

       futhark-test, futhark-cuda, futhark-c

COPYRIGHT

       2013-2024, DIKU, University of Copenhagen