Files
paddlepaddle--paddle/paddle/phi/kernels/gpu/layer_norm_grad_kernel.cu
T
2026-07-13 12:40:42 +08:00

304 lines
13 KiB
Plaintext

// Copyright (c) 2022 PaddlePaddle Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "paddle/phi/kernels/layer_norm_grad_kernel.h"
#include "paddle/common/flags.h"
#include "paddle/phi/backends/gpu/gpu_context.h"
#include "paddle/phi/core/kernel_registry.h"
#include "paddle/phi/kernels/cast_kernel.h"
#include "paddle/phi/kernels/full_kernel.h"
#include "paddle/phi/kernels/funcs/layer_norm_impl.cu.h"
#include "paddle/phi/kernels/funcs/layer_norm_util.h"
#if defined(PADDLE_WITH_CUDA) && !defined(PADDLE_WITH_HIP) && !defined(_WIN32)
#include "paddle/phi/kernels/funcs/fast_ln_v2.h"
#endif
#ifdef PADDLE_WITH_CUDA
#include "paddle/phi/kernels/gpu/rms_norm_cuda_kernel.h"
#endif
COMMON_DECLARE_bool(use_apex_layer_norm_kernel);
namespace phi {
enum class LayerNormGadKernelVariant { FAST_LN_V2, GENERIC };
static inline LayerNormGadKernelVariant LayerNormGradKernelDispatch(
const DataType weight_type,
const DataType input_type,
const DataType output_type,
const DataType compute_type,
const uint32_t hidden_size,
const int64_t x_numel,
const DenseTensor* scale,
const DenseTensor* bias) {
#if defined(PADDLE_WITH_CUDA) && !defined(PADDLE_WITH_HIP) && !defined(_WIN32)
if (FLAGS_use_apex_layer_norm_kernel) {
if (funcs::fast_ln_v2::has_fast_ln_v2_bwd_kernel(
weight_type, input_type, output_type, compute_type, hidden_size)) {
return LayerNormGadKernelVariant::FAST_LN_V2;
}
PADDLE_THROW(common::errors::InvalidArgument(
"FLAGS_use_apex_layer_norm_kernel requires inputs supported by "
"fast_ln_v2 backward kernel."));
}
if (FLAGS_use_accuracy_compatible_kernel) {
return LayerNormGadKernelVariant::GENERIC;
}
if (scale != nullptr && bias != nullptr && input_type != DataType::FLOAT32 &&
hidden_size != 4096 && hidden_size > 1024 && hidden_size <= 10240 &&
x_numel <= std::numeric_limits<uint32_t>::max()) {
// using fast_ln_v2 only sm > 70 and x_numel <= uint32_max
auto prop = funcs::fast_ln_v2::GetDeviceProp();
if (prop->major > 7 &&
funcs::fast_ln_v2::has_fast_ln_v2_bwd_kernel(
weight_type, input_type, output_type, compute_type, hidden_size)) {
return LayerNormGadKernelVariant::FAST_LN_V2;
}
}
#endif
return LayerNormGadKernelVariant::GENERIC;
}
template <typename T, typename Context>
void LayerNormGradKernel(const Context& dev_ctx,
const DenseTensor& x,
const optional<DenseTensor>& scale_opt,
const optional<DenseTensor>& bias_opt,
const DenseTensor& mean,
const DenseTensor& variance,
const DenseTensor& out_grad,
double epsilon,
int begin_norm_axis,
DenseTensor* x_grad,
DenseTensor* scale_grad,
DenseTensor* bias_grad) {
if (x.numel() == 0) {
dev_ctx.template Alloc<T>(x_grad);
if (scale_grad) {
Full<T, Context>(dev_ctx, scale_grad->dims(), 0, scale_grad);
if (scale_opt.get_ptr() && x.dtype() != scale_opt.get().dtype()) {
CastKernel<T, Context>(
dev_ctx, *scale_grad, scale_opt.get().dtype(), scale_grad);
}
}
if (bias_grad) {
Full<T, Context>(dev_ctx, bias_grad->dims(), 0, bias_grad);
if (bias_opt.get_ptr() && x.dtype() != bias_opt.get().dtype()) {
CastKernel<T, Context>(
dev_ctx, *bias_grad, bias_opt.get().dtype(), bias_grad);
}
}
return;
}
using U = funcs::LayerNormParamType<T>;
// d_x, d_scale, d_bias may be nullptr
auto* d_x = x_grad;
auto* d_scale = scale_grad;
auto* d_bias = bias_grad;
auto* scale = scale_opt.get_ptr();
auto* bias = bias_opt.get_ptr();
auto* d_y = &out_grad;
const auto& x_dims = x.dims();
auto matrix_dim = common::flatten_to_2d(x_dims, begin_norm_axis);
int64_t batch_size = static_cast<int64_t>(matrix_dim[0]);
int64_t feature_size = static_cast<int64_t>(matrix_dim[1]);
auto* x_data = x.data<T>();
auto* d_y_data = d_y->data<T>();
auto* mean_data = mean.data<U>();
auto* var_data = variance.data<U>();
auto* d_x_data = (d_x == nullptr ? nullptr : dev_ctx.template Alloc<T>(d_x));
auto x_dtype = x.dtype();
DataType scale_bias_dtype;
if (scale != nullptr) {
scale_bias_dtype = scale->dtype();
} else {
// FIXME(zengjinle): do not find a better way to get the right
// data type of the d_scale and d_bias if scale == nullptr.
if (bias != nullptr) {
scale_bias_dtype = bias->dtype();
} else {
scale_bias_dtype = x_dtype;
}
}
#define PADDLE_LAUNCH_LAYERNORM_BWD(ScaleBiasT, IsScaleBiasSameDTypeWithX) \
do { \
auto* scale_data = \
(scale == nullptr ? nullptr : scale->data<ScaleBiasT>()); \
auto* d_scale_data = \
(d_scale == nullptr ? nullptr \
: dev_ctx.template Alloc<ScaleBiasT>(d_scale)); \
auto* d_bias_data = \
(d_bias == nullptr ? nullptr \
: dev_ctx.template Alloc<ScaleBiasT>(d_bias)); \
auto* d_x_data = \
(d_x == nullptr ? nullptr : dev_ctx.template Alloc<T>(d_x)); \
funcs::LayerNormBackward<T, U, IsScaleBiasSameDTypeWithX>(x_data, \
d_y_data, \
scale_data, \
mean_data, \
var_data, \
d_x_data, \
d_scale_data, \
d_bias_data, \
epsilon, \
batch_size, \
feature_size, \
dev_ctx); \
} while (0)
#define PADDLE_LAUNCH_FAST_LAYERNORM_V2_BWD(ScaleBiasT) \
do { \
auto stream = dev_ctx.stream(); \
auto place = x.place(); \
auto* scale_data = \
(scale == nullptr ? nullptr : scale->data<ScaleBiasT>()); \
auto* d_scale_data = \
(d_scale == nullptr ? nullptr \
: dev_ctx.template Alloc<ScaleBiasT>(d_scale)); \
auto* d_bias_data = \
(d_bias == nullptr ? nullptr \
: dev_ctx.template Alloc<ScaleBiasT>(d_bias)); \
auto* d_x_data = \
(d_x == nullptr ? nullptr : dev_ctx.template Alloc<T>(d_x)); \
funcs::fast_ln_v2::LaunchNormBwd<T, Context>(dev_ctx, \
stream, \
place, \
x_data, \
scale_data, \
mean_data, \
var_data, \
d_y_data, \
d_x_data, \
d_scale_data, \
d_bias_data, \
scale_bias_dtype, \
x_dtype, \
x_grad->dtype(), \
compute_dtype, \
feature_size, \
batch_size, \
feature_size, \
epsilon); \
} while (0)
auto compute_dtype = CppTypeToDataType<U>::Type();
auto kernel_variant = LayerNormGradKernelDispatch(scale_bias_dtype,
x_dtype,
x_dtype,
compute_dtype,
feature_size,
x.numel(),
scale,
bias);
switch (kernel_variant) {
#if defined(PADDLE_WITH_CUDA) && !defined(PADDLE_WITH_HIP) && !defined(_WIN32)
case LayerNormGadKernelVariant::FAST_LN_V2:
if (scale_bias_dtype == x_dtype) {
PADDLE_LAUNCH_FAST_LAYERNORM_V2_BWD(T);
} else {
PADDLE_LAUNCH_FAST_LAYERNORM_V2_BWD(U);
}
break;
#endif
case LayerNormGadKernelVariant::GENERIC:
default:
#ifdef PADDLE_WITH_CUDA
if ((FLAGS_use_accuracy_compatible_kernel ||
(!isPowerOfTwo(feature_size) && feature_size > 1024)) &&
scale_bias_dtype == x_dtype) {
auto* scale_data = (scale == nullptr ? nullptr : scale->data<T>());
auto* d_scale_data =
(d_scale == nullptr ? nullptr : dev_ctx.template Alloc<T>(d_scale));
auto* d_bias_data =
(d_bias == nullptr ? nullptr : dev_ctx.template Alloc<T>(d_bias));
auto* d_x_data =
(d_x == nullptr ? nullptr : dev_ctx.template Alloc<T>(d_x));
LayerNormBwdCompatKernel<T, Context>(dev_ctx,
d_y_data,
x_data,
scale_data,
mean_data,
var_data,
d_x_data,
d_scale_data,
d_bias_data,
epsilon,
batch_size,
feature_size);
} else {
#endif
if (scale_bias_dtype == x_dtype) {
PADDLE_LAUNCH_LAYERNORM_BWD(T, true);
} else {
PADDLE_LAUNCH_LAYERNORM_BWD(U, false);
}
#ifdef PADDLE_WITH_CUDA
}
#endif
}
#undef PADDLE_LAUNCH_LAYERNORM_BWD
#undef PADDLE_LAUNCH_FAST_LAYERNORM_V2_BWD
}
} // namespace phi
#ifdef PADDLE_WITH_HIP
// MIOPEN do not support double
PD_REGISTER_KERNEL(layer_norm_grad,
GPU,
ALL_LAYOUT,
phi::LayerNormGradKernel,
float,
phi::float16) {
if (kernel_key.dtype() == phi::DataType::FLOAT16) {
kernel->OutputAt(1).SetDataType(phi::DataType::FLOAT32);
kernel->OutputAt(2).SetDataType(phi::DataType::FLOAT32);
}
}
#elif CUDNN_VERSION_MIN(8, 1, 0)
PD_REGISTER_KERNEL(layer_norm_grad,
GPU,
ALL_LAYOUT,
phi::LayerNormGradKernel,
float,
double,
phi::float16,
phi::bfloat16) {
if (kernel_key.dtype() == phi::DataType::FLOAT16) {
kernel->OutputAt(1).SetDataType(phi::DataType::FLOAT32);
kernel->OutputAt(2).SetDataType(phi::DataType::FLOAT32);
}
}
#else
PD_REGISTER_KERNEL(layer_norm_grad,
GPU,
ALL_LAYOUT,
phi::LayerNormGradKernel,
float,
double,
phi::float16) {
if (kernel_key.dtype() == phi::DataType::FLOAT16) {
kernel->OutputAt(1).SetDataType(phi::DataType::FLOAT32);
kernel->OutputAt(2).SetDataType(phi::DataType::FLOAT32);
}
}
#endif