futhark-cuda¶
SYNOPSIS¶
futhark cuda [options…] <program.fut>
DESCRIPTION¶
futhark cuda
translates a Futhark program to C code invoking CUDA
kernels, and either compiles that C code with gcc(1) 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, and GCC is invoked with -O
, -lm
, and -std=c99
. The
resulting program will otherwise behave exactly as one compiled with
futhark c
.
futhark cuda
uses -lcuda -lnvrtc
to link. If using
--library
, you will need to do the same when linking the final
binary.
OPTIONS¶
- -h
Print help text to standard output and exit.
- --library
Generate a library instead of an executable. Appends
.c
/.h
to the name indicated by the-o
option to determine output file names.- -o outfile
Where to write the result. If the source program is named
foo.fut
, this defaults tofoo
.- --safe
Ignore
unsafe
in program and perform safety checks unconditionally.- -v verbose
Enable debugging output. If compilation fails due to a compiler error, the result of the last successful compiler step will be printed to standard error.
- -V
Print version information on standard output and exit.
- -W
Do not print any warnings.
- --Werror
Treat warnings as errors.
EXECUTABLE OPTIONS¶
Generated executables accept the same options as those generated by
futhark-c. The -t
option behaves as with
futhark-opencl. For commonality, the options use OpenCL
nomenclature (“group” instead of “thread block”).
The following additional options are accepted.
- --default-group-size=INT
The default size of thread blocks that are launched. Capped to the hardware limit if necessary.
- --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).
- --dump-cuda=FILE
Don’t run the program, but instead dump the embedded CUDA kernels to the indicated file. Useful if you want to see what is actually being executed.
- --dump-ptx=FILE
Don’t run the program, but instead dump the PTX-compiled version of the embedded kernels to the indicated file.
- --load-cuda=FILE
Instead of using the embedded CUDA kernels, load them from the indicated file.
- --load-ptx=FILE
Load PTX code from the indicated file.
- --nvrtc-option=OPT
Add an additional build option to the string passed to NVRTC. Refer to the CUDA documentation for which options are supported. Be careful - some options can easily result in invalid results.
- --print-sizes
Print all sizes that can be set with
-size
or--tuning
.- --size=ASSIGNMENT
Set a configurable run-time parameter to the given value.
ASSIGNMENT
must be of the formNAME=INT
Use--print-sizes
to see which names are available.- --tuning=FILE
Read size=value assignments from the given file.
ENVIRONMENT¶
If run without --library
, futhark cuda
will invoke gcc(1)
to compile the generated C program into a binary. This only works if
gcc
can find the necessary CUDA libraries. On most systems, CUDA
is installed in /usr/local/cuda
, which is not part of the default
gcc
search path. You may need to set the following environment
variables before running futhark cuda
:
LIBRARY_PATH=/usr/local/cuda/lib64
LD_LIBRARY_PATH=/usr/local/cuda/lib64/
CPATH=/usr/local/cuda/include