103 lines
3.4 KiB
Plaintext
103 lines
3.4 KiB
Plaintext
// Copyright (c) 2022 PaddlePaddle Authors. All Rights Reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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// clang-format will try to sort headers according to google c++ style,
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// and that cause compiling problems.
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// clang-format off
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#include "paddle/phi/kernels/gelu_kernel.h"
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#include "paddle/phi/backends/gpu/gpu_context.h"
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#include "paddle/phi/common/amp_type_traits.h"
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#include "paddle/phi/core/dense_tensor.h"
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#include "paddle/phi/core/kernel_registry.h"
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#include "paddle/phi/kernels/funcs/broadcast_function.h"
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#include "paddle/phi/kernels/gpu/gelu_funcs.h"
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// clang-format on
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COMMON_DECLARE_bool(use_fast_math);
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COMMON_DECLARE_bool(use_accuracy_compatible_kernel);
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namespace phi {
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template <typename T>
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struct GeluWithApproximateFunctor {
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using MT = typename MPTypeTrait<T>::Type;
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inline HOSTDEVICE T operator()(T arg_x) {
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// this function is tanh approximation of gelu
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MT x = static_cast<MT>(arg_x);
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MT one = static_cast<MT>(1);
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MT half = static_cast<MT>(0.5);
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MT kAlpha = M_SQRT2 * M_2_SQRTPI * MT(0.5);
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auto tanh_out =
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tanh(kAlpha * (x + static_cast<MT>(GELU_CONSTANT) * (x * x * x)));
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MT out = half * x * (one + tanh_out);
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return static_cast<T>(out);
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}
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};
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template <typename T>
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struct GeluWithoutApproximateFunctor {
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using MT = typename MPTypeTrait<T>::Type;
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inline HOSTDEVICE T operator()(T arg_x) {
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// actual gelu with approximation = false
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MT x = static_cast<MT>(arg_x);
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// return static_cast<T>(x * normcdf(x));
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constexpr MT kAlpha = M_SQRT1_2;
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return static_cast<T>(x * MT(0.5) * (MT(1) + std::erf(x * kAlpha)));
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}
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};
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template <typename T, typename Context>
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void GeluKernel(const Context& dev_ctx,
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const DenseTensor& x,
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bool approximate,
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DenseTensor* out) {
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dev_ctx.template Alloc<T>(out);
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if (out && out->numel() == 0) {
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return;
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}
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std::vector<const DenseTensor*> ins = {&x};
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std::vector<DenseTensor*> outs = {out};
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if (approximate) {
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#if defined(__NVCC__) || defined(__HIPCC__)
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if (std::is_same<T, dtype::float16>::value &&
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!FLAGS_use_accuracy_compatible_kernel) {
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size_t n = x.numel();
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const auto* in_ptr = reinterpret_cast<const __half*>(x.data<T>());
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auto* out_ptr = reinterpret_cast<__half*>(out->data<T>());
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if (TryLaunchFP16FastGeluFwdVectorizeCUDAKernel(
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dev_ctx, in_ptr, out_ptr, n)) {
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return;
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}
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}
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#endif
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using Functor = GeluWithApproximateFunctor<T>;
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funcs::ElementwiseKernel<T, Functor, 1>(dev_ctx, ins, &outs, Functor());
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} else {
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using Functor = GeluWithoutApproximateFunctor<T>;
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funcs::ElementwiseKernel<T, Functor, 1>(dev_ctx, ins, &outs, Functor());
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}
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}
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} // namespace phi
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PD_REGISTER_KERNEL(gelu,
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GPU,
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ALL_LAYOUT,
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phi::GeluKernel,
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float,
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double,
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phi::float16,
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phi::bfloat16) {}
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