vllm/csrc/quantization/cutlass_w8a8/scaled_mm_c2x.cuh
Luka Govedič 8d59dbb000
[Kernel] Add per-tensor and per-token AZP epilogues (#5941)
Co-authored-by: Tyler Michael Smith <tyler@neuralmagic.com>
2024-08-06 18:17:08 +00:00

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#pragma once
#include <stddef.h>
#include <torch/all.h>
#include <ATen/cuda/CUDAContext.h>
// clang-format will break include orders
// clang-format off
#include "cute/tensor.hpp"
#include "cute/atom/mma_atom.hpp"
#include "cutlass/numeric_types.h"
#include "cutlass/cutlass.h"
#include "cutlass/gemm_coord.h"
#include "cutlass/arch/mma_sm75.h"
#include "cutlass/arch/arch.h"
#include "cutlass/arch/mma.h"
#include "cutlass/gemm/device/gemm.h"
#include "cutlass/gemm/device/gemm_universal_adapter.h"
#include "cutlass/epilogue/threadblock/fusion/visitors.hpp"
#include "cutlass/gemm/kernel/default_gemm_universal_with_visitor.h"
#include "broadcast_load_epilogue_c2x.hpp"
#include "common.hpp"
// clang-format on
using namespace cute;
/*
Epilogue functions can be defined to post-process the output before it is
written to GPU memory.
Epilogues must contain a public type named EVTCompute of type Sm80EVT,
as well as a static prepare_args function that constructs an
EVTCompute::Arguments struct.
*/
namespace vllm {
// Wrappers for the GEMM kernel that is used to guard against compilation on
// architectures that will never use the kernel. The purpose of this is to
// reduce the size of the compiled binary.
// __CUDA_ARCH__ is not defined in host code, so this lets us smuggle the ifdef
// into code that will be executed on the device where it is defined.
template <typename Kernel>
struct enable_sm75_to_sm80 : Kernel {
template <typename... Args>
CUTLASS_DEVICE static void invoke(Args&&... args) {
#if defined __CUDA_ARCH__ && __CUDA_ARCH__ >= 750 && __CUDA_ARCH__ < 800
Kernel::invoke(std::forward<Args>(args)...);
#endif
}
};
template <typename Kernel>
struct enable_sm80_to_sm89 : Kernel {
template <typename... Args>
CUTLASS_DEVICE static void invoke(Args&&... args) {
#if defined __CUDA_ARCH__ && __CUDA_ARCH__ >= 800 && __CUDA_ARCH__ < 890
Kernel::invoke(std::forward<Args>(args)...);
#endif
}
};
template <typename Kernel>
struct enable_sm89_to_sm90 : Kernel {
template <typename... Args>
CUTLASS_DEVICE static void invoke(Args&&... args) {
#if defined __CUDA_ARCH__ && __CUDA_ARCH__ >= 890 && __CUDA_ARCH__ < 900
Kernel::invoke(std::forward<Args>(args)...);
#endif
}
};
/*
* This class provides the common load descriptors for the
* ScaledEpilogue[...] classes
*/
template <typename ElementD, typename OutputTileThreadMap>
struct ScaledEpilogueBase {
protected:
using Accum = cutlass::epilogue::threadblock::VisitorAccFetch;
template <typename T>
using ColOrScalarLoad =
cutlass::epilogue::threadblock::VisitorColOrScalarBroadcast<
OutputTileThreadMap, T, Stride<Int<1>, Int<0>, Int<0>>>;
template <typename T>
using RowOrScalarLoad =
cutlass::epilogue::threadblock::VisitorRowOrScalarBroadcast<
OutputTileThreadMap, T, Stride<Int<0>, Int<1>, Int<0>>>;
template <typename T>
using ColLoad = cutlass::epilogue::threadblock::VisitorColBroadcast<
OutputTileThreadMap, T, Stride<Int<1>, Int<0>, Int<0>>>;
template <typename T>
using RowLoad = cutlass::epilogue::threadblock::VisitorRowBroadcast<
OutputTileThreadMap, T, Stride<Int<0>, Int<1>, Int<0>>>;
template <typename T>
using RowOrZeroLoad =
cutlass::epilogue::threadblock::VisitorRowOrZeroBroadcast<
OutputTileThreadMap, T, Stride<Int<0>, Int<1>, Int<0>>>;
// This utility function constructs the arguments for the load descriptors
// from a tensor. It can handle both row and column, as well as row/column or
// scalar cases.
template <typename Descriptor, typename T>
static auto args_from_tensor(torch::Tensor const& tensor) {
using Arguments = typename Descriptor::Arguments;
auto* data_ptr = static_cast<T*>(tensor.data_ptr());
if constexpr (std::is_same_v<Descriptor, ColOrScalarLoad<T>> ||
std::is_same_v<Descriptor, RowOrScalarLoad<T>>) {
return Arguments{data_ptr, tensor.numel() != 1};
} else {
// it would technically work but no use case as data_ptr is never nullptr
static_assert(!std::is_same_v<Descriptor, RowOrZeroLoad<T>>);
return Arguments{data_ptr};
}
}
// This overload handles the case where there might not be a tensor, in which
// case a nullptr is passed and a constant (0) is used.
template <typename Descriptor, typename T>
static auto args_from_tensor(c10::optional<torch::Tensor> const& tensor) {
static_assert(std::is_same_v<Descriptor, RowOrZeroLoad<T>>);
using Arguments = typename Descriptor::Arguments;
auto* data_ptr = tensor ? static_cast<T*>(tensor->data_ptr()) : nullptr;
return Arguments{data_ptr};
}
};
/*
This epilogue function defines a quantized GEMM operation similar to
torch._scaled_mm.
A and B may be both either int8 or fp8_e4m3. A can be quantized per-tensor or
per-row. B can be quantized per-tensor or per-column.
Any combination of per-tensor and per-row or column is supported.
A and B must have symmetric quantization (zero point == 0).
So the GEMM operation is D = (a_scales * A) (b_scales * B), where the
scales are applied elementwise with numpy-style broadcasting.
ScaleA and ScaleB define the epilogue functions that apply the scales for
the A and B operands respectively. These scales may be either per-tensor or
per row or column.
*/
template <typename ElementD, typename OutputTileThreadMap>
struct ScaledEpilogue
: private ScaledEpilogueBase<ElementD, OutputTileThreadMap> {
private:
using SUPER = ScaledEpilogueBase<ElementD, OutputTileThreadMap>;
using Accum = typename SUPER::Accum;
using ScaleA = typename SUPER::template ColOrScalarLoad<float>;
using ScaleB = typename SUPER::template RowOrScalarLoad<float>;
using Compute0 = cutlass::epilogue::threadblock::VisitorCompute<
cutlass::multiplies, float, float,
cutlass::FloatRoundStyle::round_to_nearest>;
using EVTCompute0 =
cutlass::epilogue::threadblock::Sm80EVT<Compute0, ScaleB, Accum>;
using Compute1 = cutlass::epilogue::threadblock::VisitorCompute<
cutlass::multiplies, ElementD, float,
cutlass::FloatRoundStyle::round_to_nearest>;
public:
using EVTCompute =
cutlass::epilogue::threadblock::Sm80EVT<Compute1, ScaleA, EVTCompute0>;
using ArgumentType = typename EVTCompute::Arguments;
static ArgumentType prepare_args(torch::Tensor const& a_scales,
torch::Tensor const& b_scales) {
auto a_args = SUPER::template args_from_tensor<ScaleA, float>(a_scales);
auto b_args = SUPER::template args_from_tensor<ScaleB, float>(b_scales);
typename EVTCompute0::Arguments evt0_args{b_args};
return ArgumentType{a_args, evt0_args};
}
};
/*
* This epilogue performs the same operation as ScaledEpilogue, but adds a bias.
* This bias can also be used in the per-tensor azp case, where the activation
* zero point (azp) is used to compute an azp correction term,
* which is folded into the bias.
*
* The bias tensor must be per-output channel.
* ScaleA and ScaleB can be per-tensor or per-token/per-channel.
*/
template <typename ElementD, typename OutputTileThreadMap>
struct ScaledEpilogueBias
: protected ScaledEpilogueBase<ElementD, OutputTileThreadMap> {
protected:
using SUPER = ScaledEpilogueBase<ElementD, OutputTileThreadMap>;
using Accum = typename SUPER::Accum;
using ScaleA = typename SUPER::template ColOrScalarLoad<float>;
using ScaleB = typename SUPER::template RowOrScalarLoad<float>;
using Bias = typename SUPER::template RowLoad<ElementD>;
using Compute0 = cutlass::epilogue::threadblock::VisitorCompute<
cutlass::multiplies, float, float,
cutlass::FloatRoundStyle::round_to_nearest>;
using EVTCompute0 =
cutlass::epilogue::threadblock::Sm80EVT<Compute0, ScaleB, Accum>;
using Compute1 = cutlass::epilogue::threadblock::VisitorCompute<
cutlass::multiply_add, ElementD, float,
cutlass::FloatRoundStyle::round_to_nearest>;
public:
using EVTCompute = cutlass::epilogue::threadblock::Sm80EVT<Compute1, ScaleA,
EVTCompute0, Bias>;
using ArgumentType = typename EVTCompute::Arguments;
static ArgumentType prepare_args(torch::Tensor const& a_scales,
torch::Tensor const& b_scales,
torch::Tensor const& bias) {
auto a_args = SUPER::template args_from_tensor<ScaleA, float>(a_scales);
auto b_args = SUPER::template args_from_tensor<ScaleB, float>(b_scales);
auto bias_args = SUPER::template args_from_tensor<Bias, ElementD>(bias);
typename EVTCompute0::Arguments evt0_args{b_args};
return ArgumentType{a_args, evt0_args, bias_args};
}
};
/*
* This epilogue directly supports per-tensor azp in int32 form.
* As opposed to the per-token epilogue below, this epilogue only has an azp_adj
* term, which should already be multiplied with the scalar azp.
* The azp_adj term is a 1D tensor of shape (1,n), computed as azp * J @ B.
*
* This epilogue also supports bias, which remains per-channel.
*/
template <typename ElementD, typename OutputTileThreadMap>
struct ScaledEpilogueBiasAzp
: protected ScaledEpilogueBase<ElementD, OutputTileThreadMap> {
private:
using SUPER = ScaledEpilogueBase<ElementD, OutputTileThreadMap>;
using Accum = typename SUPER::Accum;
using ScaleA = typename SUPER::template ColOrScalarLoad<float>;
using ScaleB = typename SUPER::template RowOrScalarLoad<float>;
using Bias = typename SUPER::template RowOrZeroLoad<ElementD>;
// This is the full AZP term, azp * J @ B, shape (1,n)
using AzpWithAdj = typename SUPER::template RowLoad<int32_t>;
// Compute float(accum - azp_adj), both operands are int32_t
using ComputeAzp = cutlass::epilogue::threadblock::VisitorCompute<
cutlass::minus, float, int32_t,
cutlass::FloatRoundStyle::round_to_nearest>;
using EVTComputeAzp =
cutlass::epilogue::threadblock::Sm80EVT<ComputeAzp, Accum, AzpWithAdj>;
using ComputeScaleB = cutlass::epilogue::threadblock::VisitorCompute<
cutlass::multiplies, float, float,
cutlass::FloatRoundStyle::round_to_nearest>;
using EVTComputeScaleB =
cutlass::epilogue::threadblock::Sm80EVT<ComputeScaleB, ScaleB,
EVTComputeAzp>;
using ComputeScaleBiasA = cutlass::epilogue::threadblock::VisitorCompute<
cutlass::multiply_add, ElementD, float,
cutlass::FloatRoundStyle::round_to_nearest>;
public:
using EVTCompute =
cutlass::epilogue::threadblock::Sm80EVT<ComputeScaleBiasA, ScaleA,
EVTComputeScaleB, Bias>;
using ArgumentType = typename EVTCompute::Arguments;
static ArgumentType prepare_args(torch::Tensor const& a_scales,
torch::Tensor const& b_scales,
torch::Tensor const& azp_adj,
c10::optional<torch::Tensor> const& bias) {
auto a_args = SUPER::template args_from_tensor<ScaleA, float>(a_scales);
auto b_args = SUPER::template args_from_tensor<ScaleB, float>(b_scales);
auto bias_args = SUPER::template args_from_tensor<Bias, ElementD>(bias);
auto azp_adj_args =
SUPER::template args_from_tensor<AzpWithAdj, int32_t>(azp_adj);
typename EVTComputeAzp::Arguments evt_azp_args{{}, azp_adj_args};
typename EVTComputeScaleB::Arguments evt_scale_b_args{b_args, evt_azp_args};
return ArgumentType{a_args, evt_scale_b_args, bias_args};
}
};
/*
* This epilogue supports per-token azp by computing and applying
* the correction term using a rank-1 update. If the term were materialized,
* it would require O(m*n) space, and this way it only requires O(m+n) space.
* The azp term is a 1D tensor of shape (m,1), and represents the unscaled zero
* point for each row of A.
* The azp_adj term is a 1D tensor of shape (1,n), computed as J @ B.
*
* This epilogue also supports bias, which remains per-channel.
*/
template <typename ElementD, typename OutputTileThreadMap>
struct ScaledEpilogueBiasAzpToken
: protected ScaledEpilogueBase<ElementD, OutputTileThreadMap> {
private:
using SUPER = ScaledEpilogueBase<ElementD, OutputTileThreadMap>;
using Accum = typename SUPER::Accum;
using ScaleA = typename SUPER::template ColOrScalarLoad<float>;
using ScaleB = typename SUPER::template RowOrScalarLoad<float>;
using Bias = typename SUPER::template RowOrZeroLoad<ElementD>;
// Per-token azp term, shape (m,1)
using Azp = typename SUPER::template ColLoad<int32_t>;
// This is the AZP adjustment term, J @ B, shape (1,n)
using AzpAdj = typename SUPER::template RowLoad<int32_t>;
// Compute azp * azp_adj
using ComputeAzp = cutlass::epilogue::threadblock::VisitorCompute<
cutlass::multiplies, int32_t, int32_t,
cutlass::FloatRoundStyle::round_to_nearest>;
using EVTComputeAzp =
cutlass::epilogue::threadblock::Sm80EVT<ComputeAzp, Azp, AzpAdj>;
// Compute float(accum - azp*azp_adj), all operands are int32_t
using ComputeAcc = cutlass::epilogue::threadblock::VisitorCompute<
cutlass::minus, float, int32_t,
cutlass::FloatRoundStyle::round_to_nearest>;
using EVTComputeAcc =
cutlass::epilogue::threadblock::Sm80EVT<ComputeAcc, Accum, EVTComputeAzp>;
using ComputeScaleB = cutlass::epilogue::threadblock::VisitorCompute<
cutlass::multiplies, float, float,
cutlass::FloatRoundStyle::round_to_nearest>;
using EVTComputeScaleB =
cutlass::epilogue::threadblock::Sm80EVT<ComputeScaleB, ScaleB,
EVTComputeAcc>;
using ComputeScaleBiasA = cutlass::epilogue::threadblock::VisitorCompute<
cutlass::multiply_add, ElementD, float,
cutlass::FloatRoundStyle::round_to_nearest>;
public:
using EVTCompute =
cutlass::epilogue::threadblock::Sm80EVT<ComputeScaleBiasA, ScaleA,
EVTComputeScaleB, Bias>;
using ArgumentType = typename EVTCompute::Arguments;
static ArgumentType prepare_args(torch::Tensor const& a_scales,
torch::Tensor const& b_scales,
torch::Tensor const& azp_adj,
torch::Tensor const& azp,
c10::optional<torch::Tensor> const& bias) {
auto a_args = SUPER::template args_from_tensor<ScaleA, float>(a_scales);
auto b_args = SUPER::template args_from_tensor<ScaleB, float>(b_scales);
auto bias_args = SUPER::template args_from_tensor<Bias, ElementD>(bias);
auto azp_args = SUPER::template args_from_tensor<Azp, int32_t>(azp);
auto azp_adj_args =
SUPER::template args_from_tensor<AzpAdj, int32_t>(azp_adj);
typename EVTComputeAzp::Arguments evt_azp_args{azp_args, azp_adj_args};
typename EVTComputeAcc::Arguments evt_acc_args{{}, evt_azp_args};
typename EVTComputeScaleB::Arguments evt_scale_b_args{b_args, evt_acc_args};
return ArgumentType{a_args, evt_scale_b_args, bias_args};
}
};
template <typename Arch, template <typename> typename ArchGuard,
typename ElementAB_, typename ElementD_,
template <typename, typename> typename Epilogue_, typename TileShape,
typename WarpShape, typename InstructionShape, int32_t MainLoopStages,
typename FP8MathOperator = cutlass::arch::OpMultiplyAdd>
struct cutlass_2x_gemm {
using ElementAB = ElementAB_;
using ElementD = ElementD_;
using ElementAcc =
typename std::conditional<std::is_same_v<ElementAB, int8_t>, int32_t,
float>::type;
using Operator =
typename std::conditional<std::is_same_v<ElementAB, int8_t>,
cutlass::arch::OpMultiplyAddSaturate,
FP8MathOperator>::type;
using OutputTileThreadMap =
cutlass::epilogue::threadblock::OutputTileThreadLayout<
TileShape, WarpShape, float, 4, 1 /* epilogue stages */
>;
using Epilogue = Epilogue_<ElementD, OutputTileThreadMap>;
using EVTCompute = typename Epilogue::EVTCompute;
using D = cutlass::epilogue::threadblock::VisitorAuxStore<
OutputTileThreadMap, ElementD, cutlass::FloatRoundStyle::round_to_nearest,
Stride<int64_t, Int<1>, Int<0>>>;
using EVTD = cutlass::epilogue::threadblock::Sm80EVT<D, EVTCompute>;
// clang-format off
using RowMajor = typename cutlass::layout::RowMajor;
using ColumnMajor = typename cutlass::layout::ColumnMajor;
using KernelType =
ArchGuard<typename cutlass::gemm::kernel::DefaultGemmWithVisitor<
ElementAB, RowMajor, cutlass::ComplexTransform::kNone, 16,
ElementAB, ColumnMajor, cutlass::ComplexTransform::kNone, 16,
float, cutlass::layout::RowMajor, 4,
ElementAcc, float, cutlass::arch::OpClassTensorOp,
Arch,
TileShape, WarpShape, InstructionShape,
EVTD,
cutlass::gemm::threadblock::ThreadblockSwizzleStreamK,
MainLoopStages, Operator,
1 /* epilogue stages */
>::GemmKernel>;
// clang-format on
using Op = cutlass::gemm::device::GemmUniversalAdapter<KernelType>;
};
template <typename Gemm, typename... EpilogueArgs>
inline void cutlass_gemm_caller(torch::Tensor& out, torch::Tensor const& a,
torch::Tensor const& b,
EpilogueArgs&&... epilogue_params) {
using ElementAB = typename Gemm::ElementAB;
using ElementD = typename Gemm::ElementD;
int32_t m = a.size(0);
int32_t n = b.size(1);
int32_t k = a.size(1);
cutlass::gemm::GemmCoord problem_size{m, n, k};
int64_t lda = a.stride(0);
int64_t ldb = b.stride(1);
int64_t ldc = out.stride(0);
using StrideC = Stride<int64_t, Int<1>, Int<0>>;
StrideC c_stride{ldc, Int<1>{}, Int<0>{}};
auto a_ptr = static_cast<ElementAB const*>(a.data_ptr());
auto b_ptr = static_cast<ElementAB const*>(b.data_ptr());
auto c_ptr = static_cast<ElementD*>(out.data_ptr());
typename Gemm::D::Arguments d_args{c_ptr, c_stride};
using Epilogue = typename Gemm::Epilogue;
auto evt_args =
Epilogue::prepare_args(std::forward<EpilogueArgs>(epilogue_params)...);
typename Gemm::EVTD::Arguments epilogue_args{
evt_args,
d_args,
};
typename Gemm::Op::Arguments args{
cutlass::gemm::GemmUniversalMode::kGemmSplitKParallel, // universal mode
problem_size, // problem size
1, // batch count
epilogue_args,
a_ptr,
b_ptr,
nullptr,
nullptr,
0,
0,
0,
0,
lda,
ldb,
ldc,
ldc};
// Launch the CUTLASS GEMM kernel.
typename Gemm::Op gemm_op;
size_t workspace_size = gemm_op.get_workspace_size(args);
auto const workspace_options =
torch::TensorOptions().dtype(torch::kUInt8).device(a.device());
auto workspace = torch::empty(workspace_size, workspace_options);
auto stream = at::cuda::getCurrentCUDAStream(a.get_device());
CUTLASS_CHECK(gemm_op.can_implement(args));
cutlass::Status status = gemm_op(args, workspace.data_ptr(), stream);
CUTLASS_CHECK(status);
}
template <typename Gemm, typename FallbackGemm, typename... EpilogueArgs>
inline void fallback_cutlass_gemm_caller(torch::Tensor& out,
torch::Tensor const& a,
torch::Tensor const& b,
EpilogueArgs&&... args) {
// In some cases, the GPU isn't able to accommodate the
// shared memory requirements of the Gemm. In such cases, use
// the FallbackGemm instead.
static const int max_shared_mem_per_block_opt_in =
get_cuda_max_shared_memory_per_block_opt_in(0);
size_t const gemm_shared_mem_size =
sizeof(typename Gemm::KernelType::SharedStorage);
size_t const fallback_gemm_shared_mem_size =
sizeof(typename FallbackGemm::KernelType::SharedStorage);
if (gemm_shared_mem_size <= max_shared_mem_per_block_opt_in) {
return cutlass_gemm_caller<Gemm>(out, a, b,
std::forward<EpilogueArgs>(args)...);
} else {
TORCH_CHECK(fallback_gemm_shared_mem_size <=
max_shared_mem_per_block_opt_in);
return cutlass_gemm_caller<FallbackGemm>(
out, a, b, std::forward<EpilogueArgs>(args)...);
}
}
} // namespace vllm