Files
2026-07-13 12:40:42 +08:00

178 lines
6.8 KiB
C++

// Copyright (c) 2023 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.
/* Copyright (c) 2022, NVIDIA CORPORATION. All rights reserved. */
/*This code is copied from NVIDIA apex:
* https://github.com/NVIDIA/apex
* with minor changes. */
#pragma once
#include "ln_bwd_kernels.h" // NOLINT
#include "ln_fwd_kernels.h" // NOLINT
#include "ln_utils.h" // NOLINT
namespace phi {
namespace layer_norm {
template <uint32_t HIDDEN_SIZE_,
typename weight_t_,
typename input_t_,
typename output_t_,
typename compute_t_,
typename index_t_,
uint32_t THREADS_PER_CTA_>
struct KernelTraitsBase {
using weight_t = weight_t_;
using input_t = input_t_;
using output_t = output_t_;
using compute_t = compute_t_;
using index_t = index_t_;
enum { HIDDEN_SIZE = HIDDEN_SIZE_ };
enum { THREADS_PER_CTA = THREADS_PER_CTA_ };
enum { THREADS_PER_WARP = 32 };
};
template <uint32_t HIDDEN_SIZE_,
typename weight_t_,
typename input_t_,
typename output_t_,
typename compute_t_,
typename index_t_,
uint32_t THREADS_PER_CTA_,
uint32_t BYTES_PER_LDG_,
typename Base = KernelTraitsBase<HIDDEN_SIZE_,
weight_t_,
input_t_,
output_t_,
compute_t_,
index_t_,
THREADS_PER_CTA_>>
struct KernelTraitsFinalize : public Base {
enum { ROWS_PER_CTA = Base::THREADS_PER_CTA / Base::THREADS_PER_WARP };
static_assert((int)ROWS_PER_CTA <= (int)Base::THREADS_PER_WARP); // NOLINT
// Bytes per global load from the input.
enum { BYTES_PER_LDG = BYTES_PER_LDG_ };
// Number of elements fetched by a global load.
enum { ELTS_PER_LDG = BYTES_PER_LDG / sizeof(compute_t_) };
// Bytes per global store of the weights.
enum { BYTES_PER_STG = ELTS_PER_LDG * sizeof(weight_t_) };
static_assert(
sizeof(BYTES_PER_LDG) == 4,
"Conflict-free smem transpose only implemented for 4B compute type!");
static_assert(Base::THREADS_PER_CTA == ROWS_PER_CTA * Base::THREADS_PER_WARP,
"We assume one warp per row!");
// The total number of BYTES_PER_LDG-wide words in a hidden vector.
enum { COLS = HIDDEN_SIZE_ * sizeof(compute_t_) / BYTES_PER_LDG };
static_assert(COLS * BYTES_PER_LDG == HIDDEN_SIZE_ * sizeof(compute_t_));
// Shared memory size to transpose the CTA result.
enum { SMEM_BYTES_TRANSPOSE = Base::THREADS_PER_CTA * BYTES_PER_LDG };
// Shared memory size to coalesce the CTA result.
enum { SMEM_BYTES_OUTPUT = Base::THREADS_PER_WARP * BYTES_PER_LDG };
// Shared memory requirement per CTA.
enum {
SMEM_BYTES_PER_CTA = 2 * SMEM_BYTES_TRANSPOSE + 2 * SMEM_BYTES_OUTPUT
};
// The type of the reducer.
using Reducer = layer_norm::Reducer<compute_t_, 1, 1, 1>;
// Condition for the whole CTA to participate in syncthreads.
static_assert(COLS % Base::THREADS_PER_WARP == 0);
enum { CTAS = COLS / Base::THREADS_PER_WARP };
};
////////////////////////////////////////////////////////////////////////////////////////////////////
template <typename weight_t_,
typename input_t_,
typename output_t_,
typename compute_t_,
typename index_t_,
uint32_t HIDDEN_SIZE_,
uint32_t CTAS_PER_ROW_,
uint32_t WARPS_M_,
uint32_t WARPS_N_,
uint32_t BYTES_PER_LDG_ = 16,
typename Base =
KernelTraitsBase<HIDDEN_SIZE_,
weight_t_,
input_t_,
output_t_,
compute_t_,
index_t_,
WARPS_M_ * WARPS_N_ * THREADS_PER_WARP>>
struct KernelTraits : public Base {
using input_t = typename Base::input_t;
using weight_t = typename Base::weight_t;
using compute_t = typename Base::compute_t;
using output_t = typename Base::output_t;
using index_t = typename Base::index_t;
enum { CTAS_PER_ROW = CTAS_PER_ROW_ };
enum { WARPS_M = WARPS_M_ };
enum { WARPS_N = WARPS_N_ };
enum { COLS = HIDDEN_SIZE_ };
enum { HIDDEN_SIZE = HIDDEN_SIZE_ };
enum { BYTES_PER_LDG = BYTES_PER_LDG_ };
enum { NUM_ELTS = BYTES_PER_LDG / sizeof(input_t) };
enum { THREADS_PER_ROW = WARPS_N * THREADS_PER_WARP };
enum { THREADS_PER_CTA = WARPS_M * THREADS_PER_ROW };
enum { ROWS_PER_CTA = WARPS_M };
enum { BYTES_PER_ROW = COLS * sizeof(input_t) };
enum { BYTES_PER_ROW_PER_CTA = THREADS_PER_ROW * BYTES_PER_LDG };
// Multi-row per CTA not supported for multi-CTA => no smem for WGRAD needed
enum {
SMEM_BYTES_WGRAD =
CTAS_PER_ROW > 1 ? 0 : ROWS_PER_CTA* COLS * sizeof(compute_t)
};
static_assert(WARPS_M == 1 || CTAS_PER_ROW == 1);
using reduce_t = typename layer_norm::TypeToVec2<compute_t>::Type;
using Reducer = layer_norm::Reducer<reduce_t, CTAS_PER_ROW, WARPS_M, WARPS_N>;
enum { SMEM_BYTES_DGRAD = Reducer::SMEM_BYTES };
enum { SMEM_BYTES = SMEM_BYTES_DGRAD + SMEM_BYTES_WGRAD };
using Ivec = layer_norm::Vec<input_t, NUM_ELTS>;
using Ovec = layer_norm::Vec<output_t, NUM_ELTS>;
using Wvec = layer_norm::Vec<weight_t, NUM_ELTS>;
using Cvec = layer_norm::Vec<compute_t, NUM_ELTS>;
enum { ELTS_PER_LDG = BYTES_PER_LDG / sizeof(input_t) };
// Assume that each thread can handle the same number of elements in the
// output and weights as in the input.
static_assert(sizeof(input_t) >= sizeof(output_t));
static_assert(sizeof(input_t) >= sizeof(weight_t));
// The number of columns fetched per load from input: one per thread.
enum { VEC_COLS_PER_LDG = CTAS_PER_ROW * THREADS_PER_ROW };
// The total number of vectorized loads/stores per hidden vector.
enum { VEC_COLS = COLS / ELTS_PER_LDG };
// The number of loads per thread for the input.
enum { LDGS = VEC_COLS / VEC_COLS_PER_LDG };
static_assert(LDGS * VEC_COLS_PER_LDG == VEC_COLS);
// static_assert(LDGS * BYTES_PER_ROW_PER_CTA * CTAS_PER_ROW == BYTES_PER_ROW,
// "");
using Stats = layer_norm::Stats<compute_t, CTAS_PER_ROW, WARPS_M, WARPS_N>;
enum { SMEM_BYTES_FWD = Stats::SMEM_BYTES };
};
} // namespace layer_norm
} // namespace phi