Files
nvfp4-megamoe-kernel/dsv4/ops/custom_ops.py
biondizzle 3fb3c925af Restructure: cutedsl/ -> dsv4/ with proper layering
- Split bridge.py -> ops/quantize.py, ops/layouts.py, ops/gemm_runner.py
- Renamed classes: CuTeDSLNvfp4Linear -> Nvfp4Linear, etc.
- Moved kernel code to dsv4/kernels/ (gemm, attention, compressor, decode, cuda)
- Moved PyTorch bridges to dsv4/ops/
- Moved nn.Module layers to dsv4layers/
- Moved reference implementations to dsv4/reference/
- Moved vendored CUTLASS code to vendored/
- Archived ~190 debug tests to tests/archive/
- Kept ~15 canonical tests in tests/unit/
- Updated all import paths
- Added stubs for future components (model/, cache/, loader/)
- Updated pyproject.toml: dsv4-inference package name
2026-05-21 17:30:44 +00:00

101 lines
3.4 KiB
Python

"""torch.library.custom_op wrappers for CuTeDSL NVFP4 kernels.
Dynamo (torch.compile fullgraph) cannot trace through CuTeDSL internals
(JIT compilation, cute.compile, etc.). By wrapping the runner calls in
torch.library.custom_op, Dynamo treats them as opaque black boxes.
This is the correct approach per PyTorch's extensibility model:
- custom_op is the supported way to make Dynamo skip tracing
- autograd.Function does NOT work reliably with fullgraph mode
- The runner's _run_impl is already cudagraph-safe
The registry pattern: custom ops can only take tensor/scalar arguments.
We store runners in a global dict keyed by integer ID, and pass the ID
as an int parameter. During Dynamo tracing, the fake impl returns a
correctly-shaped tensor without touching the runner. During execution,
the real impl looks up the runner and calls _run_impl.
"""
import torch
# ---------------------------------------------------------------------------
# Runner registry — maps integer IDs to runner objects
# ---------------------------------------------------------------------------
_next_runner_id = 0
_runner_registry: dict[int, object] = {}
def register_runner(runner) -> int:
"""Register a CuTeDSL runner and return its integer ID."""
global _next_runner_id
rid = _next_runner_id
_next_runner_id += 1
_runner_registry[rid] = runner
return rid
def get_runner(rid: int):
"""Look up a runner by ID."""
return _runner_registry[rid]
# ---------------------------------------------------------------------------
# NVFP4 Linear GEMM custom op (single linear layer)
# ---------------------------------------------------------------------------
@torch.library.custom_op("nvfp4::linear_gemm", mutates_args=())
def nvfp4_linear_gemm(
x: torch.Tensor,
runner_id: int,
out_features: int,
) -> torch.Tensor:
"""Opaque NVFP4 linear GEMM for torch.compile.
Args:
x: (M, K) BF16 input
runner_id: integer key into the runner registry
out_features: output dimension (for shape inference)
Returns:
(M, out_features) BF16 output
"""
runner = get_runner(runner_id)
return runner._run_impl(x)
@nvfp4_linear_gemm.register_fake
def _(x, runner_id, out_features):
return torch.empty(x.shape[0], out_features, dtype=torch.bfloat16, device=x.device)
# ---------------------------------------------------------------------------
# NVFP4 MoE custom op (L1 + SiLU + L2 grouped GEMM)
# ---------------------------------------------------------------------------
@torch.library.custom_op("nvfp4::moe_gemm", mutates_args=())
def nvfp4_moe_gemm(
hidden_states: torch.Tensor,
topk_weights: torch.Tensor,
topk_ids: torch.Tensor,
runner_id: int,
hidden_size: int,
) -> torch.Tensor:
"""Opaque NVFP4 MoE GEMM for torch.compile.
Args:
hidden_states: (M, K) BF16 input
topk_weights: (M, top_k) float32 routing weights
topk_ids: (M, top_k) int32 expert IDs
runner_id: integer key into the runner registry
hidden_size: output dimension (for shape inference)
Returns:
(M, hidden_size) BF16 output
"""
runner = get_runner(runner_id)
return runner._run_impl(hidden_states, topk_weights, topk_ids)
@nvfp4_moe_gemm.register_fake
def _(hidden_states, topk_weights, topk_ids, runner_id, hidden_size):
return torch.empty(
hidden_states.shape[0], hidden_size,
dtype=torch.bfloat16, device=hidden_states.device,
)