AMD GCN Function Attributes#
These function attributes are supported by the AMD GCN back end:
- amdgpu_hsa_kernel#
This attribute indicates that the corresponding function should be compiled as a kernel function, that is an entry point that can be invoked from the host via the HSA runtime library. By default functions are only callable only from other GCN functions.
This attribute is implicitly applied to any function named
main
, using default parameters.Kernel functions may return an integer value, which will be written to a conventional place within the HSA “kernargs” region.
The attribute parameters configure what values are passed into the kernel function by the GPU drivers, via the initial register state. Some values are used by the compiler, and therefore forced on. Enabling other options may break assumptions in the compiler and/or run-time libraries.
private_segment_buffer
Set
enable_sgpr_private_segment_buffer
flag. Always on (required to locate the stack).dispatch_ptr
Set
enable_sgpr_dispatch_ptr
flag. Always on (required to locate the launch dimensions).queue_ptr
Set
enable_sgpr_queue_ptr
flag. Always on (required to convert address spaces).kernarg_segment_ptr
Set
enable_sgpr_kernarg_segment_ptr
flag. Always on (required to locate the kernel arguments, “kernargs”).dispatch_id
Set
enable_sgpr_dispatch_id
flag.flat_scratch_init
Set
enable_sgpr_flat_scratch_init
flag.private_segment_size
Set
enable_sgpr_private_segment_size
flag.grid_workgroup_count_X
Set
enable_sgpr_grid_workgroup_count_x
flag. Always on (required to use OpenACC/OpenMP).grid_workgroup_count_Y
Set
enable_sgpr_grid_workgroup_count_y
flag.grid_workgroup_count_Z
Set
enable_sgpr_grid_workgroup_count_z
flag.workgroup_id_X
Set
enable_sgpr_workgroup_id_x
flag.workgroup_id_Y
Set
enable_sgpr_workgroup_id_y
flag.workgroup_id_Z
Set
enable_sgpr_workgroup_id_z
flag.workgroup_info
Set
enable_sgpr_workgroup_info
flag.private_segment_wave_offset
Set
enable_sgpr_private_segment_wave_byte_offset
flag. Always on (required to locate the stack).work_item_id_X
Set
enable_vgpr_workitem_id
parameter. Always on (can’t be disabled).work_item_id_Y
Set
enable_vgpr_workitem_id
parameter. Always on (required to enable vectorization.)work_item_id_Z
Set
enable_vgpr_workitem_id
parameter. Always on (required to use OpenACC/OpenMP).