futhark-hip¶
SYNOPSIS¶
futhark hip [options…] <program.fut>
DESCRIPTION¶
futhark hip
translates a Futhark program to C code invoking HIP
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 hip
uses -lhiprtc -lamdhip64
to link. If using
--library
, you will need to do the same when linking the final
binary. Although the HIP backend can be made to work on NVIDIA GPUs,
you are probably better off using the very similar
futhark-cuda.
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 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-hip=FILE
Don’t run the program, but instead dump the embedded HIP kernels to the indicated file. Useful if you want to see what is actually being executed.
- --load-hip=FILE
Instead of using the embedded HIP kernels, load them from the indicated file.
- --build-option=OPT
Add an additional build option to the string passed to the kernel compiler (HIPRTC). Refer to the HIP documentation for which options are supported. Be careful - some options can easily result in invalid results.
ENVIRONMENT¶
If run without --library
, futhark hip
will invoke a C
compiler to compile the generated C program into a binary. This only
works if the C compiler can find the necessary HIP libraries.