Metal Kernels

Just toying around with compute

Building

mkdir -p build && cd build
cmake ..
ninja

metal-cpp is downloaded automatically on first configure if not already present.

Usage

./metal_kernel <file.metal> <kernel_name> <grid_size> [buffer_specs...]

Grid size

Format	Dispatch mode	Description
N	dispatchThreads	N total threads, auto threadgroup size
N,T	dispatchThreads	N total threads, threadgroup size T
NxT	dispatchThreadgroups	N threadgroups of T threads each

Buffer specs

Format: type:count[:mode[:value]]

• type: float or uint
• count: number of elements
• mode:
  • in (default) — filled with sequential data (0, 1, 2, ...)
  • out — zero-initialized, printed after execution
  • const — filled with value (for constant uniforms)

Examples

# vector_add: two input buffers added element-wise into an output buffer
./metal_kernel vector_add.metal vector_add 1024 \
    float:1024:in float:1024:in float:1024:out

# softmax: 1 threadgroup of 256 threads, with a constant length parameter
./metal_kernel softmax.metal softmax 1x256 \
    float:256:in float:256:out uint:1:const:256

Built-in verification runs automatically for vector_add and softmax kernels.