[sgl-kernel] support hadamard (#11663)

scripts/ci/ci_install_dependency.sh

@@ -62,7 +62,7 @@ fi
 $PIP_CMD list
 
 # Install additional dependencies
-$PIP_CMD install mooncake-transfer-engine==0.3.6.post1 nvidia-cuda-nvrtc-cu12 py-spy huggingface_hub[hf_xet] $PIP_INSTALL_SUFFIX
+$PIP_CMD install mooncake-transfer-engine==0.3.6.post1 nvidia-cuda-nvrtc-cu12 py-spy scipy huggingface_hub[hf_xet] $PIP_INSTALL_SUFFIX
 
 if [ "$IS_BLACKWELL" != "1" ]; then
     # For lmms_evals evaluating MMMU

sgl-kernel/CMakeLists.txt

@@ -60,6 +60,7 @@ FetchContent_Declare(
 )
 FetchContent_Populate(repo-deepgemm)
 
+# fmt
 FetchContent_Declare(
     repo-fmt
     GIT_REPOSITORY https://github.com/fmtlib/fmt
@@ -113,6 +114,15 @@ FetchContent_Declare(
 )
 FetchContent_Populate(repo-mscclpp)
 
+# fast-hadamard-transform
+FetchContent_Declare(
+    repo-fast-hadamard-transform
+    GIT_REPOSITORY https://github.com/sgl-project/fast-hadamard-transform.git
+    GIT_TAG 48f3c13764dc2ec662ade842a4696a90a137f1bc
+    GIT_SHALLOW OFF
+)
+FetchContent_Populate(repo-fast-hadamard-transform)
+
 # ccache option
 option(ENABLE_CCACHE "Whether to use ccache" ON)
 find_program(CCACHE_FOUND ccache)
@@ -138,6 +148,7 @@ include_directories(
     ${repo-flashinfer_SOURCE_DIR}/include
     ${repo-flashinfer_SOURCE_DIR}/csrc
     ${repo-mscclpp_SOURCE_DIR}/include
+    ${repo-fast-hadamard-transform}/csrc
 )
 
 set(SGL_KERNEL_CUDA_FLAGS
@@ -329,6 +340,9 @@ set(SOURCES
     "${repo-flashinfer_SOURCE_DIR}/csrc/renorm.cu"
     "${repo-flashinfer_SOURCE_DIR}/csrc/sampling.cu"
 
+    "${repo-fast-hadamard-transform_SOURCE_DIR}/csrc/fast_hadamard_transform_cuda.cu"
+    "${repo-fast-hadamard-transform_SOURCE_DIR}/csrc/fast_hadamard_transform.cpp"
+
     "${repo-flash-attention_SOURCE_DIR}/csrc/flash_attn/src/flash_fwd_sparse_hdim128_bf16_causal_sm80.cu"
     "${repo-flash-attention_SOURCE_DIR}/csrc/flash_attn/src/flash_fwd_sparse_hdim128_bf16_sm80.cu"
     "${repo-flash-attention_SOURCE_DIR}/csrc/flash_attn/src/flash_fwd_sparse_hdim128_fp16_causal_sm80.cu"

sgl-kernel/csrc/common_extension.cc

@@ -540,6 +540,24 @@ TORCH_LIBRARY_FRAGMENT(sgl_kernel, m) {
       "stride_a, Tensor stride_b, Tensor stride_d, Tensor problem_sizes, Tensor expert_offsets, Tensor workspace) -> "
       "()");
   m.impl("es_fp8_blockwise_scaled_grouped_mm", &es_fp8_blockwise_scaled_grouped_mm);
+
+  /*
+   * From hadamard-transform
+   */
+  m.def("fast_hadamard_transform(Tensor x, float scale) -> Tensor");
+  m.impl("fast_hadamard_transform", torch::kCUDA, &fast_hadamard_transform);
+
+  m.def("fast_hadamard_transform_12N(Tensor x, float scale) -> Tensor");
+  m.impl("fast_hadamard_transform_12N", torch::kCUDA, &fast_hadamard_transform_12N);
+
+  m.def("fast_hadamard_transform_20N(Tensor x, float scale) -> Tensor");
+  m.impl("fast_hadamard_transform_20N", torch::kCUDA, &fast_hadamard_transform_20N);
+
+  m.def("fast_hadamard_transform_28N(Tensor x, float scale) -> Tensor");
+  m.impl("fast_hadamard_transform_28N", torch::kCUDA, &fast_hadamard_transform_28N);
+
+  m.def("fast_hadamard_transform_40N(Tensor x, float scale) -> Tensor");
+  m.impl("fast_hadamard_transform_40N", torch::kCUDA, &fast_hadamard_transform_40N);
 }
 
 REGISTER_EXTENSION(common_ops)

sgl-kernel/include/sgl_kernel_ops.h

@@ -837,3 +837,11 @@ void es_fp8_blockwise_scaled_grouped_mm(
     const torch::Tensor& problem_sizes,
     const torch::Tensor& expert_offsets,
     const torch::Tensor& workspace);
+/*
+ * From fast-hadamard-transform
+ */
+torch::Tensor fast_hadamard_transform(torch::Tensor& x, double scale);
+torch::Tensor fast_hadamard_transform_12N(torch::Tensor& x, double scale);
+torch::Tensor fast_hadamard_transform_20N(torch::Tensor& x, double scale);
+torch::Tensor fast_hadamard_transform_28N(torch::Tensor& x, double scale);
+torch::Tensor fast_hadamard_transform_40N(torch::Tensor& x, double scale);

sgl-kernel/python/sgl_kernel/__init__.py

@@ -270,6 +270,13 @@ from sgl_kernel.gemm import (
     silu_and_mul_scaled_fp4_grouped_quant,
 )
 from sgl_kernel.grammar import apply_token_bitmask_inplace_cuda
+from sgl_kernel.hadamard import (
+    hadamard_transform,
+    hadamard_transform_12n,
+    hadamard_transform_20n,
+    hadamard_transform_28n,
+    hadamard_transform_40n,
+)
 from sgl_kernel.kvcacheio import (
     transfer_kv_all_layer,
     transfer_kv_all_layer_mla,

sgl-kernel/python/sgl_kernel/hadamard.py

@@ -0,0 +1,21 @@
+import torch
+
+
+def hadamard_transform(x: torch.Tensor, scale: float = 1.0) -> torch.Tensor:
+    return torch.ops.sgl_kernel.fast_hadamard_transform.default(x, scale)
+
+
+def hadamard_transform_12n(x: torch.Tensor, scale: float = 1.0) -> torch.Tensor:
+    return torch.ops.sgl_kernel.fast_hadamard_transform_12N.default(x, scale)
+
+
+def hadamard_transform_20n(x: torch.Tensor, scale: float = 1.0) -> torch.Tensor:
+    return torch.ops.sgl_kernel.fast_hadamard_transform_20N.default(x, scale)
+
+
+def hadamard_transform_28n(x: torch.Tensor, scale: float = 1.0) -> torch.Tensor:
+    return torch.ops.sgl_kernel.fast_hadamard_transform_28N.default(x, scale)
+
+
+def hadamard_transform_40n(x: torch.Tensor, scale: float = 1.0) -> torch.Tensor:
+    return torch.ops.sgl_kernel.fast_hadamard_transform_40N.default(x, scale)

sgl-kernel/tests/test_hadamard.py

@@ -0,0 +1,78 @@
+import math
+
+import pytest
+import torch
+import torch.nn.functional as F
+from einops import rearrange, repeat
+from scipy.linalg import hadamard
+from sgl_kernel import hadamard_transform
+
+
+def hadamard_transform_ref(x, scale=1.0):
+    """
+    x: (..., dim)
+    out: (..., dim)
+    """
+    if hadamard is None:
+        raise ImportError("Please install scipy")
+    x_shape = x.shape
+    dim = x.shape[-1]
+    x = x.reshape(-1, dim)
+    log_dim = math.ceil(math.log2(dim))
+    dim_padded = 2**log_dim
+    if dim != dim_padded:
+        x = F.pad(x, (0, dim_padded - dim))
+    out = F.linear(
+        x,
+        torch.tensor(hadamard(dim_padded, dtype=float), dtype=x.dtype, device=x.device),
+    )
+    out = out * scale
+    return out[..., :dim].reshape(*x_shape)
+
+
+@pytest.mark.parametrize("dtype", [torch.float32, torch.float16, torch.bfloat16])
+@pytest.mark.parametrize(
+    "dim",
+    [1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 137, 1024, 2048, 4096, 8192, 16384, 32768],
+)
+def test_fast_hadamard_transform(dim, dtype):
+    device = "cuda"
+
+    if dtype == torch.float32:
+        rtol, atol = 3e-4, 3e-3
+    elif dtype == torch.bfloat16:
+        rtol, atol = 1e-2, 5e-2
+    else:  # float16
+        rtol, atol = 3e-3, 5e-3
+
+    torch.random.manual_seed(0)
+    batch_size = 15
+
+    x = torch.randn(batch_size, dim, device=device, dtype=dtype)
+    x_ref = x.detach().clone().to(torch.float32)
+    x_pt = x.detach().clone()
+
+    scale = 1 / math.sqrt(dim)
+
+    out = hadamard_transform(x, scale=scale)
+    out_ref = hadamard_transform_ref(x_ref, scale=scale)
+    out_pt = hadamard_transform_ref(x_pt, scale=scale)
+
+    torch.testing.assert_close(
+        out_pt.float(),
+        out_ref,
+        rtol=rtol,
+        atol=atol,
+        msg="Reference implementations mismatch",
+    )
+    torch.testing.assert_close(
+        out.float(),
+        out_ref,
+        rtol=rtol,
+        atol=atol,
+        msg="fast_hadamard_transform output mismatch",
+    )
+
+
+if __name__ == "__main__":
+    pytest.main([__file__])