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[CK] [CK_Tile] Add FMHA scaffolding to CK kernel dispatcher (#5260) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit ## Motivation The CK Tile dispatcher currently supports GEMM and Grouped Convolution but has no support for Fused Multi-Head Attention (FMHA). The example/ck_tile/01_fmha folder contains a comprehensive FMHA implementation with forward, backward, split-KV, paged-KV, append-KV, and batch-prefill kernels across multiple GPU architectures — but there is no unified dispatch layer for it. This PR ports the FMHA stack into the dispatcher, following the same architectural patterns established by GEMM and Grouped Convolution, enabling runtime kernel selection, JIT compilation from Python, and a declarative C++ example flow. Autotuning heuristics to follow. ## Technical Details This PR adds FMHA scaffolding to the CK dispatcher framework, mirroring GEMM's layered architecture. Seven new C++ runtime headers provide type definitions (coexisting with upstream headers via __has_include, requiring zero modifications to example/ck_tile/01_fmha/), a problem builder with 18+ setters, Signature + Algorithm kernel key matching, a virtual kernel instance, a DECL_FMHA_KERNEL_SET macro with wildcard support and named tile/wave/warp setters, arch-aware registry with JSON export, and a dispatcher with seqtune-aware selection, configurable timing, and multi-stage execution plans for split-KV (two-stage) and backward (three-stage). The codegen pipeline is driven by a fmha_arch_specs.json capturing per-arch tile tables and pipeline constraints for five architectures (gfx90a/942/950/1100/1201), migrated from hardcoded logic in 01_fmha/codegen/, with supporting modules for C++ symbol mappings, validation rules, and named receipt profiles (ck_default, flash, pytorch, aiter, fp32, fp8). Python integration (fmha_utils.py) mirrors the C++ layer with JIT compilation, parallel multi-kernel builds, HIP memory management via ctypes, tolerance-based validation, and a NumPy CPU reference with GQA support. Twenty-seven C++ and thirty-two Python examples cover the full feature surface — forward, split-KV, masks, bias, dropout, GQA, backward, append-KV, batch prefill, fp8, logits soft cap, sink tokens, and parameter sweeps — all JIT-compiled on the fly. ## Test Plan Seven test files cover the runtime types, codegen, and end-to-end correctness. C++ unit tests validate the problem builder, dispatcher planning (single-stage for forward/paged-KV/append-KV; multi-stage for split-KV and backward), registry operations, and the kernel-set declaration macro. Python unit tests verify codegen emission, profile filtering, and 15 validation rules for masks, hdim constraints, and pipeline requirements. GPU execution validation in 01_basic_fmha --validate reports zero errors across 65,536 elements with max absolute error of 7.29e-05. A gold-standard parity suite (test_fmha_parity.py) runs 14 configurations through both the upstream tile_example_fmha_fwd and the dispatcher, comparing exit codes to confirm behavioral parity — all 14 match. ## Test Result The C++ smoke test builds and passes all 9 compiled examples, and a Python JIT sweep (29_sweep_seqlen.py) passes 7/7 configurations reaching up to 375 TFLOPS at seqlen 2048. ## Submission Checklist - [x] Look over the contributing guidelines at https://github.com/ROCm/ROCm/blob/develop/CONTRIBUTING.md#pull-requests.
CK Tile Unified Code Generators
Single source of truth for GEMM and Grouped Convolution kernel generation.
See also: Main Dispatcher README for installation and core concepts.
Shared Infrastructure
Both GEMM and Grouped Conv generators share common code via codegen_common.py:
TileConfig- Dataclass for tile dimensionsTraitConfigBase- Base for kernel trait configurations with arch-aware validationCommonTypeMappings- Dtype-to-C++ type mappingsparallel_generate()- Parallel kernel generation with per-kernel progress logging- Arch-aware expansion helpers (
valid_wave_configs,valid_warp_configs, etc.)
Quick Start
GEMM
cd dispatcher/codegen
# Generate standard FP16 kernels
python3 unified_gemm_codegen.py \
--output-dir ../build/generated_kernels \
--datatype fp16 \
--layout rcr \
--variants standard
# Generate all variants
python3 unified_gemm_codegen.py \
--output-dir ../build/generated_kernels \
--variants standard preshuffle multi_d
Grouped Convolution
cd dispatcher/codegen
# Generate forward FP16 grouped conv kernels
python3 unified_grouped_conv_codegen.py \
--output-dir ../build/generated_kernels \
--datatype fp16 \
--variant forward \
--ndim-spatial 2
# Generate backward data kernels
python3 unified_grouped_conv_codegen.py \
--output-dir ../build/generated_kernels \
--variant backward_data \
--ndim-spatial 2
Using from Python
from ctypes_utils import CodegenRunner, KernelConfig
# Generate from specific config
config = KernelConfig(tile_m=256, tile_n=256, tile_k=64)
codegen = CodegenRunner()
result = codegen.generate_from_config(config)
# Generate variant
result = codegen.generate("preshuffle")
# Generate all
results = codegen.generate_all()
Command Line Options
| Option | Values | Description |
|---|---|---|
--output-dir |
path | Output directory |
--datatype |
fp16, bf16, fp32, int8 |
Data type |
--layout |
rcr, rrr, crr, ccr |
Matrix layouts |
--gpu-target |
gfx942, gfx90a, gfx950 |
Target GPU |
--variants |
standard, preshuffle, multi_d |
Kernel variants |
--preselected |
fp16_rcr_essential, etc. |
Predefined kernel set |
Layout Notation
R= Row-major,C= Column-major- Order: A, B, C (e.g.,
rcr= A row, B col, C row)
Variants
Standard
Basic GEMM: C = A x B
PreShuffle
Optimized weight access with LDS pre-shuffling. Best for large matrices.
Multi-D
Element-wise fusion: C = op(A x B + D0 + D1 + ...)
Supported ops: PassThrough, MultiDAdd, Relu, Gelu, Sigmoid, Tanh
Output Structure
generated_kernels/
|---- gemm_fp16_rcr_compv4_..._128x128x32_....hpp # GEMM kernels
|---- gemm_fp16_rcr_compv4_..._preshuffle.hpp
|---- gemm_fp16_rcr_compv4_..._multid_Relu_d1.hpp
|---- grouped_conv_fwd_fp16_nhwgc_..._128x128x32_....hpp # Grouped conv kernels
+---- ...
Configuration Files
arch_specs.json
GPU architecture specifications (single source of truth):
{
"architectures": {
"gfx942": {
"family": "cdna3",
"warp_size": 64,
"warp_configs": [[2, 2, 1], [4, 4, 1]],
...
}
}
}
preselected_kernels.py
Curated kernel sets for common use cases.
Adding New GPU Support
See ADDING_NEW_GPU.md for complete guide.
Quick steps:
- Edit
arch_specs.json - Run
python generate_arch_specs.py - Rebuild
Troubleshooting
| Issue | Solution |
|---|---|
| "Arguments not supported" | Check tile config validity |
| Missing element-wise op | Check elementwise_ops.hpp |
| Compilation errors | Verify C++17, include paths |
More info: See ../README.md for full documentation.