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pytorch/torch/_inductor/codegen/triton_utils.py
Jason Ansel 3e1b1a30f2 Revert "[inductor] Fix issue with scalar arg handling" (#163737)
This reverts commit a8cd437183142e17ba6fc8d7b5e9dcee462d7904.

See https://github.com/pytorch/pytorch/pull/163481#issuecomment-3326310774

This PR might also cause issues with cudagraphs.

Pull Request resolved: https://github.com/pytorch/pytorch/pull/163737
Approved by: https://github.com/ezyang
ghstack dependencies: #163386, #163398, #163387, #163414, #163415, #163419, #163434, #163393, #163412, #163422, #163481, #163520, #163482
2025-09-24 07:33:12 +00:00

260 lines
8.8 KiB
Python

# mypy: allow-untyped-defs
from typing import Any, Optional
import sympy
import torch
from .. import config
from ..runtime.hints import AttrsDescriptorWrapper
from ..utils import _type_of, expr_fits_within_32bit, triton_version_uses_attrs_dict
from ..virtualized import V
from .common import (
ArgName,
ConstexprArg,
KernelArgType,
SizeArg,
TensorArg,
TMADescriptorArg,
WorkspaceArg,
)
def should_unwrap_unspec_arg(name: str):
if V.graph.is_unspec_arg(name):
# Unwrap on all devices except CPU
if V.graph.get_current_device_or_throw().type != "cpu":
return True
# Only unwrap on CPU if the input is not used as an output
if name not in V.graph.mutated_buffers:
return True
return False
def signature_of(arg: KernelArgType, *, size_dtype: Optional[str]) -> str:
if isinstance(arg, TensorArg):
# TODO: Remove fp8 special handling when Triton supports PyTorch fp8 dtypes.
# Related PR: https://github.com/triton-lang/triton/pull/2279/
if arg.dtype == torch.float8_e4m3fn:
typ = "*fp8e4nv"
elif arg.dtype == torch.float8_e5m2:
typ = "*fp8e5"
elif arg.dtype == torch.float8_e4m3fnuz:
typ = "*fp8e4b8"
elif arg.dtype == torch.float8_e5m2fnuz:
typ = "*fp8e5b16"
else:
typ = _type_of(arg.dtype)
if should_unwrap_unspec_arg(arg.buffer):
# had unwrapped 0d tensor as scalar
new_typ = typ.lstrip("*")
if new_typ in ["fp16", "bf16"]:
return "fp32"
else:
return new_typ
else:
return typ
if isinstance(arg, SizeArg):
if arg.expr is None:
if triton_version_uses_attrs_dict():
# In newer versions of Triton, the signature includes "None" args
# and their type is marked as "constexpr"
return "constexpr"
else:
# In older versions of Triton...
# From triton/runtime/jit.py
# `None` is nullptr. Implicitly convert to *i8.
return "*i8"
elif _arg_equals_1(arg) and triton_version_uses_attrs_dict():
# In new versions of Triton, if we have an equal-to-1 arg that's marked as a constant,
# it should be marked as "constexpr" in the signature.
return "constexpr"
elif isinstance(arg.expr, (float, sympy.Float)):
return "fp32"
elif isinstance(arg.expr, bool):
return "i1"
# if this is a integer
if size_dtype == "tl.int32":
return "i32"
elif size_dtype == "tl.int64":
return "i64"
elif size_dtype is None:
# no hint: we'll see if we know that this is a 32-bit int, and guard if possible.
int_max = torch.iinfo(torch.int32).max
if expr_fits_within_32bit(arg.expr):
V.graph.sizevars.check_leq(arg.expr, int_max)
return "i32"
else:
return "i64"
else:
raise NotImplementedError(f"unhandled size_dtype {size_dtype}")
if isinstance(arg, WorkspaceArg):
return _type_of(arg.dtype)
if isinstance(arg, TMADescriptorArg):
if arg.api_type == "experimental":
return "nvTmaDesc"
else:
# https://github.com/triton-lang/triton/blob/9695baed9b46cf957e08b157bb4133f4a4b331c5/python/triton/runtime/jit.py#L360-L363
assert arg.api_type == "stable"
assert arg.block_shape is not None
assert arg.dtype is not None
inner = _type_of(arg.dtype)[1:] # strip the `*`: *fp32 -> fp32
return f"tensordesc<{inner}{list(arg.block_shape)}>"
if isinstance(arg, ConstexprArg):
return "constexpr"
raise NotImplementedError(f"unhandled {type(arg)}: {arg}")
def non_constexpr_signature(signature):
new_signature = []
for arg in signature:
if not isinstance(arg, ConstexprArg):
new_signature.append(arg)
return new_signature
def signature_to_meta(
signature: list[KernelArgType],
*,
size_dtype: Optional[str],
argdefs: list[ArgName],
indices: Optional[list[int]] = None,
is_template: bool = False,
) -> dict[str, str]:
if indices is None:
indices = list(range(len(signature)))
def _decide_tl_dtype(arg):
# Even if the ks0 symbol itself is within tl.int32 range, it's
# risky to use tl.int32 dtype since we may have ks0*ks1 later
# for kernels like torch.mean when dynamic shape is enabled.
#
# Check config.triton.use_block_ptr, since Triton block pointer
# does not support 64bit indexing:
# https://gist.github.com/shunting314/6a41c776171720ce4561f202dcde0ad6
#
# If the triton metadata is for a template, don't use tl.int64 index.
# Templates like flex attention/decoding uses block pointers which
# does not support 64 bit indexing.
if (
not config.triton.use_block_ptr
and not is_template
and isinstance(arg, SizeArg)
and arg.name.startswith("ks")
):
return "tl.int64"
return size_dtype
return {
argdefs[i].name: signature_of(arg, size_dtype=_decide_tl_dtype(arg))
for i, arg in zip(indices, signature)
}
def is_unaligned_buffer(arg: TensorArg):
buf_name = arg.buffer
if buf_name in V.graph.unaligned_buffers:
return True
if buf_name in V.graph.graph_inputs:
# See Note: [Input Alignment handling in Inductor]
# For graph inputs that is not recorded in V.graph.unaligned_buffers,
# we know for sure the tensor is aligned.
return False
if buf_name in V.graph.constants:
# all constants are assumed to be aligned
return False
if V.graph.scheduler:
layout = V.graph.scheduler.get_buffer_layout(buf_name)
else:
buffer = V.graph.try_get_buffer(buf_name)
# output arg
if not buffer:
assert buf_name == V.kernel.output_node.name
layout = V.kernel.output_node.layout
else:
layout = buffer.get_layout()
if isinstance(layout, torch._inductor.ir.NonOwningLayout):
return not layout.maybe_guard_aligned()
else:
return False
def _arg_equals_1(arg: KernelArgType) -> bool:
return (
isinstance(arg, SizeArg)
and isinstance(arg.expr, (int, sympy.Integer))
and V.graph.sizevars.statically_known_equals(arg.expr, 1) # type: ignore[arg-type]
)
def equal_1_arg_indices(
args: list[KernelArgType],
*,
indices: Optional[list[int]] = None,
) -> tuple[int, ...]:
if indices is None:
indices = list(range(len(args)))
equal_to_1 = tuple(i for i, arg in zip(indices, args) if _arg_equals_1(arg))
return equal_to_1
def config_of(
args: list[KernelArgType],
*,
indices: Optional[list[int]] = None,
) -> Any:
if indices is None:
indices = list(range(len(args)))
def is_aligned(x: KernelArgType, alignment: int, include_tensor: bool) -> bool:
"""
Roughly follow triton code here:
https://github.com/triton-lang/triton/blob/5282ed890d453e10b9ee30076ef89115dd197761/python/triton/runtime/jit.py#L208-L222
"""
if isinstance(x, TensorArg):
if include_tensor:
offset_aligned = V.graph.sizevars.statically_known_multiple_of(
x.offset * x.dtype.itemsize,
alignment, # type: ignore[arg-type]
)
return offset_aligned and not is_unaligned_buffer(x)
else:
return False
if isinstance(x, SizeArg):
# TODO(voz): These are kinda redundant, if we can solve out statically_known_multiple_of with
# _maybe_evaluate_static...
if x.name.startswith("load_seed_offset"):
return False
if x.expr is None:
return False
if isinstance(x.expr, float):
return False
return V.graph.sizevars.statically_known_multiple_of(x.expr, alignment) # type: ignore[arg-type]
if isinstance(x, WorkspaceArg):
# We allocate the workspace ourselves, so it is always aligned
return True
if isinstance(x, (TMADescriptorArg, ConstexprArg)):
return False
raise NotImplementedError(f"unhandled {type(x)}: {x}")
if config.triton.divisible_by_16:
divisible_by_16 = tuple(
i
for i, arg in zip(indices, args)
if is_aligned(arg, alignment=16, include_tensor=True)
)
else:
divisible_by_16 = ()
equal_to_1 = equal_1_arg_indices(args, indices=indices)
return AttrsDescriptorWrapper(divisible_by_16, equal_to_1)