Files
LTX-2/packages/ltx-kernels/setup.py
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2026-07-07 16:57:50 +00:00

229 lines
10 KiB
Python

import os
import re
import subprocess
from pathlib import Path
import setuptools
import torch
from torch.utils.cpp_extension import CUDA_HOME, BuildExtension, CUDAExtension
ROOT = Path(__file__).resolve().parent
# cutlass headers for the blockwise GEMM kernels. Pinned to the upstream commit the
# build was validated against and fetched into a cache dir, rather than carried as a
# git submodule (keeps the public-repo sync clean and the clone CI-cacheable).
CUTLASS_REPO = "https://github.com/NVIDIA/cutlass.git"
CUTLASS_REF = "afa1772203677c5118fcd82537a9c8fefbcc7008" # v3.8.0
def _nvidia_include_dirs() -> list[str]:
"""Include dirs from pip-installed nvidia packages (e.g. cusparse headers)."""
try:
import nvidia # noqa: PLC0415
return [str(p) for pkg in Path(nvidia.__path__[0]).iterdir() if (p := pkg / "include").is_dir()]
except ImportError:
return []
def _arch_tokens() -> list[str]:
"""Normalized entries from TORCH_CUDA_ARCH_LIST (e.g. ['8.9', '9.0'])."""
raw = os.environ.get("TORCH_CUDA_ARCH_LIST", "")
return [re.sub(r"\+PTX$", "", tok).strip() for tok in raw.replace(",", " ").split() if tok.strip()]
# Arch codes the blockwise FP8 GEMM kernels support, as nvcc `sm_<code>` targets.
# SM89 ("geforce") is the generic fp8 kernel: it runs on Ada and is also the kernel
# dispatched on Blackwell (sm_100a datacenter / sm_120 consumer), so it is compiled for
# those too. The SM90 ("deep_gemm") kernel is Hopper-only and needs sm_90a (wgmma/TMA);
# it is declared-always / defined-conditionally, so it stubs out on every non-Hopper
# pass and can share a multi-arch fat binary. Ampere has no fp8 path. Entries are
# filtered to what the local nvcc can actually target (see _nvcc_arch_nums), so the
# Blackwell codes are inert until built with CUDA 12.8+.
# NOTE: the Blackwell (100a/120) path is implemented but not yet validated on real
# Blackwell hardware -- needs a B200 + CUDA 12.8 build/run pass.
_BLOCKWISE_ARCHES = ["89", "90a", "100a", "120"]
def _nvcc_arch_nums() -> set[str]:
"""Architecture numbers this nvcc can target, e.g. {'80', '86', '89', '90'}."""
try:
out = subprocess.check_output([f"{CUDA_HOME}/bin/nvcc", "--list-gpu-arch"], text=True)
except (OSError, subprocess.CalledProcessError):
return set()
return {m.group(1) for tok in out.split() if (m := re.match(r"compute_(\d+a?)$", tok.strip()))}
def _blockwise_gencode() -> tuple[list[str], bool]:
"""Return (``-gencode`` flags for blockwise_cpp, build_sm90).
Honors ``TORCH_CUDA_ARCH_LIST`` when set (mapping 8.9 -> sm_89, 9.0/9.0a -> sm_90a,
ignoring arches the kernels do not support); unset builds for every supported arch
this nvcc can target. The flags apply uniformly to all sources -- safe because the
SM90 source stubs itself out on non-sm_90a passes.
"""
supported = _nvcc_arch_nums()
# nvcc may report an arch either plain ("90") or suffixed ("90a"); accept either.
base = [a for a in _BLOCKWISE_ARCHES if a in supported or a.rstrip("a") in supported]
env = _arch_tokens()
if env:
sel = []
for tok in env:
if tok.startswith("8.9"):
sel.append("89")
elif tok.startswith("9.0"):
sel.append("90a")
elif tok.startswith("10.0"):
sel.append("100a")
elif tok.startswith("12.0"):
sel.append("120")
# Ampere (8.0/8.6) and other arches have no fp8 blockwise kernel.
archs = [a for a in dict.fromkeys(sel) if a in base] or base
else:
archs = base
flags = [f"-gencode=arch=compute_{a},code=sm_{a}" for a in archs]
return flags, ("90a" in archs)
def _cutlass_include() -> str:
"""Return the cutlass include dir, fetching the pinned commit on first use.
Honors ``CUTLASS_DIR`` (a prebuilt cutlass checkout, e.g. a system copy) and
otherwise caches a shallow clone of ``CUTLASS_REF`` under
``LTX_KERNELS_CACHE_DIR`` (default ``~/.cache/ltx-kernels``), so it is reused
across builds and can be restored from a CI cache. Keeps ``uv sync`` /
``pip install -e`` self-contained without a git submodule.
"""
if env := os.environ.get("CUTLASS_DIR"):
return str(Path(env) / "include")
cache_root = Path(os.environ.get("LTX_KERNELS_CACHE_DIR", Path.home() / ".cache" / "ltx-kernels"))
dest = cache_root / f"cutlass-{CUTLASS_REF}"
if not (dest / "include" / "cutlass" / "cutlass.h").is_file():
dest.mkdir(parents=True, exist_ok=True)
# Blobless partial clone of the exact pinned commit (GitHub allows fetching an
# arbitrary SHA), sparse-checked-out to include/ only: cutlass is header-only and
# the rest of the repo (tools/test/examples/python, ~85% by size) is unused.
subprocess.run(["git", "init", "-q", str(dest)], check=True)
subprocess.run(["git", "-C", str(dest), "remote", "add", "origin", CUTLASS_REPO], check=True)
# Cone-mode sparse checkout of just include/. Use init + set (not "set --cone",
# whose inline flag postdates git 2.35 and is silently parsed as a pattern on older git).
subprocess.run(["git", "-C", str(dest), "sparse-checkout", "init", "--cone"], check=True)
subprocess.run(["git", "-C", str(dest), "sparse-checkout", "set", "include"], check=True)
subprocess.run(
["git", "-C", str(dest), "fetch", "-q", "--depth", "1", "--filter=blob:none", "origin", CUTLASS_REF],
check=True,
)
subprocess.run(["git", "-C", str(dest), "checkout", "-q", "FETCH_HEAD"], check=True)
return str(dest / "include")
if __name__ == "__main__":
if CUDA_HOME is None:
raise RuntimeError(
"CUDA toolkit not found (CUDA_HOME is None). ltx-kernels compiles CUDA extensions "
"and must be built on a host with the CUDA toolkit installed (nvcc on PATH or "
"CUDA_HOME set)."
)
ext_modules = []
# all2all_cpp -- unchanged.
all2all_args = ["-O3", "-Wall", "-Wextra", "-Werror", "-Wno-unused-parameter", "-Wno-attributes"]
ext_modules.append(
CUDAExtension(
name="all2all_cpp",
include_dirs=[str(ROOT / "csrc/all2all"), str(ROOT / "csrc/include"), *_nvidia_include_dirs()],
sources=[
"csrc/all2all/all2all.cpp",
"csrc/all2all/cuda/all2all_heads.cu",
"csrc/all2all/cuda/allgather.cu",
],
extra_compile_args={"cxx": all2all_args, "nvcc": ["-O3"]},
)
)
# ops_cpp -- arch-independent element ops (rms_norm_rope, rms_norm_split_rope,
# fp6 pack/unpack). Arch is driven by TORCH_CUDA_ARCH_LIST / torch defaults.
ext_modules.append(
CUDAExtension(
name="ops_cpp",
sources=[
"csrc/ops/ops_api.cpp",
"csrc/ops/fp6_bitpack.cpp",
"csrc/ops/fp6_pack.cu",
"csrc/ops/rms_norm_rope.cpp",
"csrc/ops/rms_norm_rope_cuda.cu",
"csrc/ops/rms_norm_split_rope.cpp",
"csrc/ops/rms_norm_split_rope_cuda.cu",
],
include_dirs=[str(ROOT / "csrc/ops/include"), *_nvidia_include_dirs()],
extra_compile_args={
"cxx": ["-O3", "-std=c++17"],
"nvcc": [
"-O3",
"-std=c++17",
"-U__CUDA_NO_HALF_OPERATORS__",
"-U__CUDA_NO_HALF_CONVERSIONS__",
"-U__CUDA_NO_HALF2_OPERATORS__",
"-U__CUDA_NO_BFLOAT16_CONVERSIONS__",
"--expt-relaxed-constexpr",
"--expt-extended-lambda",
"--use_fast_math",
],
},
)
)
# blockwise_cpp -- FP8 GEMM. The SM89 (GeForce) kernel is always built; the SM90
# (deep_gemm) kernel + -D__SM90__ are added whenever sm_90a is among the targets.
# Arches are an explicit -gencode list (see _blockwise_gencode): TORCH_CUDA_ARCH_LIST
# when set, else every supported arch this nvcc can target ("build for everything").
# The list is uniform across sources -- the SM90 source declares-always /
# defines-conditionally, so it compiles (as a stub) for non-sm_90a arches too. Note
# blockwise is unsupported on Ampere and fails at *runtime* there, by design.
cutlass_include = _cutlass_include()
gencode, build_sm90 = _blockwise_gencode()
blockwise_sources = [
"csrc/blockwise/api.cpp",
"csrc/blockwise/kernels/geforce/gemm.cu",
]
abi = f"-D_GLIBCXX_USE_CXX11_ABI={int(torch.compiled_with_cxx11_abi())}"
blockwise_cxx = ["-O3", "-std=c++17", "-fPIC", "-Wno-psabi", "-Wno-deprecated-declarations", abi]
blockwise_nvcc = [
"-O3",
"-std=c++17",
"--ptxas-options=-O2",
"--expt-relaxed-constexpr",
"--expt-extended-lambda",
"-U__CUDA_NO_HALF_OPERATORS__",
"-U__CUDA_NO_HALF_CONVERSIONS__",
"-U__CUDA_NO_HALF2_OPERATORS__",
"-U__CUDA_NO_BFLOAT16_CONVERSIONS__",
*gencode,
]
if build_sm90:
blockwise_sources.append("csrc/blockwise/kernels/deep_gemm/include/deep_gemm/impls/sm90_fp8_gemm_1d2d_bias.cu")
blockwise_cxx.append("-D__SM90__")
blockwise_nvcc.append("-D__SM90__")
ext_modules.append(
CUDAExtension(
name="blockwise_cpp",
sources=blockwise_sources,
include_dirs=[
f"{CUDA_HOME}/include",
f"{CUDA_HOME}/include/cccl",
str(ROOT / "csrc/blockwise"),
str(ROOT / "csrc/blockwise/kernels/deep_gemm/include"),
cutlass_include,
*_nvidia_include_dirs(),
],
libraries=["cuda", "cudart", "nvrtc"],
library_dirs=[f"{CUDA_HOME}/lib64", f"{CUDA_HOME}/lib64/stubs"],
extra_compile_args={"cxx": blockwise_cxx, "nvcc": blockwise_nvcc},
)
)
setuptools.setup(
ext_modules=ext_modules,
cmdclass={"build_ext": BuildExtension},
)