TensorRT-LLMs/cpp/tensorrt_llm/kernels/beamSearchTopkKernels.cu
Kaiyu Xie 4bb65f216f
Update TensorRT-LLM (#1274)
* Update TensorRT-LLM

---------

Co-authored-by: meghagarwal <16129366+megha95@users.noreply.github.com>
Co-authored-by: Shixiaowei02 <39303645+Shixiaowei02@users.noreply.github.com>
2024-03-12 18:15:52 +08:00

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/*
* Copyright (c) 2020-2023, NVIDIA CORPORATION. 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.
*/
#ifndef CUDART_VERSION
#error CUDART_VERSION Undefined!
#elif (CUDART_VERSION >= 11050)
#include <cub/cub.cuh>
#else
#include "3rdparty/cub/cub.cuh"
#endif
#include "tensorrt_llm/common/assert.h"
#include "tensorrt_llm/common/cudaTypeUtils.cuh"
#include "tensorrt_llm/common/cudaUtils.h"
#include "tensorrt_llm/common/reduceKernelUtils.cuh"
#include "tensorrt_llm/common/stringUtils.h"
#include "tensorrt_llm/kernels/beamSearchTopkKernels.h"
using namespace tensorrt_llm::common;
namespace tensorrt_llm
{
namespace kernels
{
template <typename T>
__device__ __forceinline__ T apply_length_penalty(T log_prob, int length, float length_penalty)
{
// score = log(prob) / (length ^ length_penalty)
if (length_penalty == 0.0f || length == 1)
{
return log_prob;
}
return log_prob / static_cast<T>(powf((float) length, length_penalty));
}
template <typename T, int MAX_K, int THREADBLOCK_SIZE>
__launch_bounds__(THREADBLOCK_SIZE) __global__
void beam_topK_kernel(T const* log_probs, int* topk_tmp_id_buf, T* topk_tmp_val_buf, bool const* finished,
int const* sequence_lengths, int const vocab_size, T diversity_rate, float length_penalty)
{
typedef cub::BlockReduce<TopK<T, MAX_K>, THREADBLOCK_SIZE> BlockReduce;
__shared__ typename BlockReduce::TempStorage temp_storage;
int thread_id = threadIdx.x;
int block_id = blockIdx.x; // batch beam index.
TopK<T, MAX_K> partial;
bool const IS_FP16 = std::is_same<T, half>::value;
const T MAX_T_VAL = (IS_FP16) ? HALF_FLT_MAX : FLT_MAX;
#pragma unroll
for (int i = 0; i < MAX_K; ++i)
{
partial.p[i] = -1;
partial.u[i] = -MAX_T_VAL;
}
#pragma unroll
for (int elem_id = thread_id; elem_id < vocab_size; elem_id += THREADBLOCK_SIZE)
{
int index = elem_id + block_id * vocab_size;
T score = length_penalty == 0.0f
? log_probs[index]
: apply_length_penalty(log_probs[index],
finished[block_id] ? sequence_lengths[block_id] : sequence_lengths[block_id] + 1, length_penalty);
partial.insert(score, index);
}
TopK<T, MAX_K> total = BlockReduce(temp_storage).Reduce(partial, reduce_topk_op<T, MAX_K>);
if (thread_id == 0)
{
int index = block_id * MAX_K;
#pragma unroll
for (int i = 0; i < MAX_K; ++i)
{
topk_tmp_id_buf[index + i] = total.p[i];
topk_tmp_val_buf[index + i] = total.u[i] + diversity_rate * (T) i;
}
}
}
template <typename T, int MAX_K, int THREADBLOCK_SIZE>
__launch_bounds__(THREADBLOCK_SIZE) __global__
void batch_topK_kernel(int* topk_tmp_id_buf, T* topk_tmp_val_buf, int* id_buf)
{
int thread_id = threadIdx.x;
int block_id = blockIdx.x;
bool const IS_FP16 = std::is_same<T, half>::value;
const T MAX_T_VAL = (IS_FP16) ? HALF_FLT_MAX : FLT_MAX;
TopK<T, MAX_K> partial;
if (thread_id == 0)
{
for (int i = 0; i < MAX_K; ++i)
{
partial.p[i] = -1;
partial.u[i] = -MAX_T_VAL;
}
int index = block_id * MAX_K * MAX_K;
for (int i = 0; i < MAX_K * MAX_K; i++)
{
partial.insert((T) topk_tmp_val_buf[index + i], topk_tmp_id_buf[index + i]);
}
index = block_id * MAX_K;
for (int i = 0; i < MAX_K; i++)
{
id_buf[index + i] = partial.p[i];
}
}
}
template <typename T, int MAX_K, int THREADBLOCK_SIZE>
__launch_bounds__(THREADBLOCK_SIZE) __global__
void batch_topK_kernel_v2(int* topk_tmp_id_buf, T* topk_tmp_val_buf, int* id_buf)
{
typedef cub::BlockReduce<TopK<T, MAX_K>, THREADBLOCK_SIZE> BlockReduce;
__shared__ typename BlockReduce::TempStorage temp_storage;
int tid = threadIdx.x;
int bid = blockIdx.x;
TopK<T, MAX_K> partial;
bool const IS_FP16 = std::is_same<T, half>::value;
const T MAX_T_VAL = (IS_FP16) ? HALF_FLT_MAX : FLT_MAX;
#pragma unroll
for (int i = 0; i < MAX_K; ++i)
{
partial.p[i] = -1;
partial.u[i] = -MAX_T_VAL;
}
int ite = MAX_K * MAX_K / THREADBLOCK_SIZE;
#pragma unroll
for (int i = 0; i < ite; i++)
{
int index = bid * MAX_K * MAX_K + i * THREADBLOCK_SIZE + tid;
partial.insert((T) topk_tmp_val_buf[index], topk_tmp_id_buf[index]);
}
TopK<T, MAX_K> total = BlockReduce(temp_storage).Reduce(partial, reduce_topk_op<T, MAX_K>);
if (tid == 0)
{
#pragma unroll
for (int i = 0; i < MAX_K; i++)
{
id_buf[bid * MAX_K + i] = total.p[i];
}
}
}
template <typename T, int BLOCK_SIZE_, int BLOCKS_PER_BEAM_>
__global__ void topk_stage_1_opt3(T const* __restrict log_probs, T* tmp_log_probs, int* topk_tmp_id_buf,
T* topk_tmp_val_buf, bool const* finished, int const* sequence_lengths, int const k, int const vocab_size,
float const length_penalty, int const* end_ids)
{
typedef cub::BlockReduce<TopK_2<T>, BLOCK_SIZE_> BlockReduce;
__shared__ typename BlockReduce::TempStorage temp_storage;
int const tid = threadIdx.x;
int const bid = blockIdx.x;
int const row_id = bid / BLOCKS_PER_BEAM_; // row id for log_probs (batchbeam index)
int const block_lane = bid % BLOCKS_PER_BEAM_; // block id for a beam
int const tmp_log_buf_index = row_id * vocab_size;
int const tmp_topk_buf_index = row_id * BLOCKS_PER_BEAM_ * k + block_lane * k;
TopK_2<T> partial;
bool const IS_FP16 = std::is_same<T, half>::value;
const T MAX_T_VAL = (IS_FP16) ? HALF_FLT_MAX : FLT_MAX;
if (finished != nullptr && finished[row_id] == true)
{
if (tid < k)
{
int const index = tmp_topk_buf_index + tid;
if (block_lane == 0 && tid == 0)
{
int const end_id = end_ids[row_id / k];
topk_tmp_id_buf[index] = tmp_log_buf_index + end_id;
topk_tmp_val_buf[index] = log_probs[tmp_log_buf_index + end_id];
}
else
{
topk_tmp_id_buf[index] = -1;
topk_tmp_val_buf[index] = -MAX_T_VAL;
}
}
return;
}
for (int elem_id = tid + block_lane * BLOCK_SIZE_; elem_id < vocab_size; elem_id += BLOCK_SIZE_ * BLOCKS_PER_BEAM_)
{
int index = elem_id + tmp_log_buf_index;
tmp_log_probs[index] = log_probs[index];
}
for (int ite = 0; ite < k; ite++)
{
partial.init();
#pragma unroll
for (int elem_id = tid + block_lane * BLOCK_SIZE_; elem_id < vocab_size;
elem_id += BLOCK_SIZE_ * BLOCKS_PER_BEAM_)
{
int index = elem_id + tmp_log_buf_index;
partial.insert(tmp_log_probs[index], index);
}
TopK_2<T> total = BlockReduce(temp_storage).Reduce(partial, reduce_topk_op_2<T>);
if (tid == 0)
{
int const index = tmp_topk_buf_index + ite;
topk_tmp_id_buf[index] = total.p;
topk_tmp_val_buf[index] = total.u;
tmp_log_probs[total.p] = -MAX_T_VAL;
}
__syncthreads();
}
}
template <typename T, int BLOCK_SIZE_, int BLOCKS_PER_BEAM_>
__global__ void topk_stage_2_opt3(int const* __restrict topk_tmp_id_buf, T* topk_tmp_val_buf, int* ids,
BeamHypotheses beam_hyps, int const* end_ids, int const vocab_size, int const k)
{
int const size = k * k * BLOCKS_PER_BEAM_;
int const tid = threadIdx.x;
int const batch_id = blockIdx.x;
bool const IS_FP16 = std::is_same<T, half>::value;
const T MAX_T_VAL = (IS_FP16) ? HALF_FLT_MAX : FLT_MAX;
float const length_penalty{beam_hyps.length_penalties == nullptr ? 1.0f : beam_hyps.length_penalties[batch_id]};
typedef cub::BlockReduce<TopK_2<T>, BLOCK_SIZE_> BlockReduce;
__shared__ typename BlockReduce::TempStorage temp_storage;
extern __shared__ char array[];
T* s_val = topk_tmp_val_buf + batch_id * size;
int* s_id = (int*) (array);
__shared__ int selected_beams;
__shared__ bool is_stop;
if (tid == 0)
{
selected_beams = 0;
is_stop = false;
}
__syncthreads();
if (beam_hyps.num_beams != nullptr)
{
int const global_batch_idx = beam_hyps.ite * beam_hyps.local_batch_size + batch_id;
if (beam_hyps.num_beams[global_batch_idx] == 0 && tid == 0)
{
// initialize the buffer
beam_hyps.min_normed_scores[global_batch_idx] = FLT_MAX;
}
else if (beam_hyps.num_beams[global_batch_idx] == k)
{
return;
}
}
TopK_2<T> partial;
// In some cases, we may encounter k finished sentences, but scores are bad.
// So, the max iteration is 2*k here
for (int ite = 0; ite < 2 * k; ite++)
{
partial.init();
#pragma unroll
for (int i = tid; i < size; i += BLOCK_SIZE_)
{
partial.insert(s_val[i], i);
}
TopK_2<T> total = BlockReduce(temp_storage).Reduce(partial, reduce_topk_op_2<T>);
if (tid == 0)
{
if (beam_hyps.num_beams != nullptr
&& topk_tmp_id_buf[batch_id * size + total.p] % vocab_size == end_ids[batch_id])
{
// if beam_token does not belong to top num_beams tokens, it should not
// be added. Refer from
// https://github.com/huggingface/transformers/blob/v4.24.0/src/transformers/generation_beam_search.py#L257
if (ite >= k)
{
s_val[total.p] = -MAX_T_VAL;
}
else
{
int const global_batch_idx = beam_hyps.ite * beam_hyps.local_batch_size + batch_id;
float const normed_score = apply_length_penalty(s_val[total.p], beam_hyps.step, length_penalty);
int const num_beam = beam_hyps.num_beams[global_batch_idx];
int beam_idx = num_beam;
// If there are beam_width finished sentences, check that the score of
// selected candidatet is higher than min_normed_score or not. If
// current score is better, replace worst one and update the
// min_normed_score.
if (num_beam == k)
{
if (normed_score < beam_hyps.min_normed_scores[global_batch_idx])
{
// end the tracing and exist this for loop
selected_beams = k;
is_stop = true;
break;
}
else
{
// find the beam index which's score = min_normed_score, erase it.
for (int j = 0; j < k; j++)
{
if (beam_hyps.normed_scores[global_batch_idx * k + j]
== beam_hyps.min_normed_scores[global_batch_idx])
{
beam_idx = j;
beam_hyps.num_beams[global_batch_idx]--;
beam_hyps.min_normed_scores[global_batch_idx] = FLT_MAX;
beam_hyps.normed_scores[global_batch_idx * k + j] = normed_score;
for (int l = 0; l < k; l++)
{
beam_hyps.min_normed_scores[global_batch_idx]
= min(beam_hyps.min_normed_scores[global_batch_idx],
beam_hyps.normed_scores[global_batch_idx * k + l]);
}
break;
}
}
}
}
int const tgt_id_offset = ((batch_id + beam_hyps.ite * beam_hyps.local_batch_size) * k + beam_idx)
* beam_hyps.max_seq_len;
beam_hyps.output_ids_tgt[tgt_id_offset + beam_hyps.step] = end_ids[batch_id];
int prev_id = (topk_tmp_id_buf[batch_id * size + total.p] / vocab_size) % k;
for (int j = beam_hyps.step - 1; j >= 0; j--)
{
int const src_idx = j * beam_hyps.batch_size * k
+ beam_hyps.ite * beam_hyps.local_batch_size * k + batch_id * k + prev_id;
beam_hyps.output_ids_tgt[tgt_id_offset + j] = beam_hyps.output_ids_src[src_idx];
prev_id = beam_hyps.parent_ids_src[src_idx];
}
int const tgt_beam_idx = global_batch_idx * k + beam_idx;
beam_hyps.sequence_lengths_tgt[tgt_beam_idx] = beam_hyps.step;
beam_hyps.normed_scores[tgt_beam_idx] = normed_score;
beam_hyps.min_normed_scores[global_batch_idx]
= min(beam_hyps.min_normed_scores[global_batch_idx], beam_hyps.normed_scores[tgt_beam_idx]);
s_val[total.p] = -MAX_T_VAL;
beam_hyps.num_beams[global_batch_idx]++;
}
}
else
{
s_id[selected_beams] = total.p;
s_val[total.p] = -MAX_T_VAL;
selected_beams++;
}
}
__syncthreads();
if (selected_beams >= k)
{
break;
}
}
if (tid < k && is_stop == false)
{
ids[batch_id * k + tid] = topk_tmp_id_buf[batch_id * size + s_id[tid]];
}
}
template <typename T, int BLOCK_SIZE, int BLOCKS_PER_BEAM>
__global__ void topk_stage_1_opt2_general(T const* __restrict log_probs, T* tmp_log_probs, int* topk_tmp_id_buf,
T* topk_tmp_val_buf, bool const* finished, int const* sequence_lengths, int const k, int const vocab_size,
float const length_penalty)
{
bool const IS_FP16 = std::is_same<T, half>::value;
const T MAX_T_VAL = (IS_FP16) ? HALF_FLT_MAX : FLT_MAX;
typedef cub::BlockReduce<TopK_2<T>, BLOCK_SIZE> BlockReduce;
__shared__ typename BlockReduce::TempStorage temp_storage;
int const tid = threadIdx.x;
int const bid = blockIdx.x;
int const row_id = bid / BLOCKS_PER_BEAM; // row id for log_probs
int const block_lane = bid % BLOCKS_PER_BEAM; // block id for a beam
int const tmp_log_buf_index = row_id * vocab_size;
int const tmp_topk_buf_index = row_id * BLOCKS_PER_BEAM * k + block_lane * k;
TopK_2<T> partial;
for (int elem_id = tid + block_lane * BLOCK_SIZE; elem_id < vocab_size; elem_id += BLOCK_SIZE * BLOCKS_PER_BEAM)
{
int index = elem_id + tmp_log_buf_index;
tmp_log_probs[index] = log_probs[index];
}
for (int ite = 0; ite < k; ite++)
{
partial.init();
#pragma unroll
for (int elem_id = tid + block_lane * BLOCK_SIZE; elem_id < vocab_size; elem_id += BLOCK_SIZE * BLOCKS_PER_BEAM)
{
int index = elem_id + tmp_log_buf_index;
partial.insert(tmp_log_probs[index], index);
}
TopK_2<T> total = BlockReduce(temp_storage).Reduce(partial, reduce_topk_op_2<T>);
if (tid == 0)
{
int const index = tmp_topk_buf_index + ite;
topk_tmp_id_buf[index] = total.p;
topk_tmp_val_buf[index] = total.u;
tmp_log_probs[total.p] = -MAX_T_VAL;
}
__syncthreads();
}
}
template <typename T, int BLOCK_SIZE, int BLOCKS_PER_BEAM>
__global__ void topk_stage_2_opt2_general(int const* __restrict topk_tmp_id_buf, T* topk_tmp_val_buf, int* ids,
BeamHypotheses beam_hyps, int const* end_ids, int const k, int const vocab_size)
{
int const size = k * k * BLOCKS_PER_BEAM;
int const tid = threadIdx.x;
int const batch_id = blockIdx.x;
bool const IS_FP16 = std::is_same<T, half>::value;
const T MAX_T_VAL = (IS_FP16) ? HALF_FLT_MAX : FLT_MAX;
float const length_penalty{beam_hyps.length_penalties == nullptr ? 1.0f : beam_hyps.length_penalties[batch_id]};
typedef cub::BlockReduce<TopK_2<T>, BLOCK_SIZE> BlockReduce;
__shared__ typename BlockReduce::TempStorage temp_storage;
extern __shared__ char array[];
T* s_val = topk_tmp_val_buf + batch_id * size;
int* s_id = (int*) (array);
__shared__ int selected_beams;
__shared__ bool is_stop;
if (tid == 0)
{
selected_beams = 0;
is_stop = false;
}
__syncthreads();
if (beam_hyps.num_beams != nullptr)
{
int const global_batch_idx = beam_hyps.ite * beam_hyps.local_batch_size + batch_id;
if (beam_hyps.num_beams[global_batch_idx] == 0 && tid == 0)
{
beam_hyps.min_normed_scores[global_batch_idx] = FLT_MAX;
}
else if (beam_hyps.num_beams[global_batch_idx] == k)
{
return;
}
}
TopK_2<T> partial;
// In some cases, we may encounter k finished sentences, but scores are bad.
// So, the max iteration is 2*k here
for (int ite = 0; ite < 2 * k; ite++)
{
partial.init();
#pragma unroll
for (int i = tid; i < size; i += BLOCK_SIZE)
{
partial.insert(s_val[i], i);
}
TopK_2<T> total = BlockReduce(temp_storage).Reduce(partial, reduce_topk_op_2<T>);
if (tid == 0)
{
if (beam_hyps.num_beams != nullptr
&& topk_tmp_id_buf[batch_id * size + total.p] % vocab_size == end_ids[batch_id])
{
// if beam_token does not belong to top num_beams tokens, it should not
// be added. Refer from
// https://github.com/huggingface/transformers/blob/v4.24.0/src/transformers/generation_beam_search.py#L257
if (ite >= k)
{
s_val[total.p] = -MAX_T_VAL;
}
else
{
int const global_batch_idx = beam_hyps.ite * beam_hyps.local_batch_size + batch_id;
float const normed_score = apply_length_penalty(s_val[total.p], beam_hyps.step, length_penalty);
int const num_beam = beam_hyps.num_beams[global_batch_idx];
int beam_idx = num_beam;
// If there are beam_width finished sentences, check that the score of
// selected candidatet is higher than min_normed_score or not. If
// current score is better, replace worst one and update the
// min_normed_score.
if (num_beam == k)
{
if (normed_score < beam_hyps.min_normed_scores[global_batch_idx])
{
// end the tracing and exist this for loop
selected_beams = k;
is_stop = true;
break;
}
else
{
// find the beam index which's score = min_normed_score, erase it.
for (int j = 0; j < k; j++)
{
if (beam_hyps.normed_scores[global_batch_idx * k + j]
== beam_hyps.min_normed_scores[global_batch_idx])
{
beam_idx = j;
beam_hyps.num_beams[global_batch_idx]--;
beam_hyps.min_normed_scores[global_batch_idx] = FLT_MAX;
beam_hyps.normed_scores[global_batch_idx * k + j] = normed_score;
for (int l = 0; l < k; l++)
{
beam_hyps.min_normed_scores[global_batch_idx]
= min(beam_hyps.min_normed_scores[global_batch_idx],
beam_hyps.normed_scores[global_batch_idx * k + l]);
}
break;
}
}
}
}
int const tgt_id_offset = ((batch_id + beam_hyps.ite * beam_hyps.local_batch_size) * k + beam_idx)
* beam_hyps.max_seq_len;
beam_hyps.output_ids_tgt[tgt_id_offset + beam_hyps.step] = end_ids[batch_id];
int prev_id = (topk_tmp_id_buf[batch_id * size + total.p] / vocab_size) % k;
for (int j = beam_hyps.step - 1; j >= 0; j--)
{
int const src_idx = j * beam_hyps.batch_size * k
+ beam_hyps.ite * beam_hyps.local_batch_size * k + batch_id * k + prev_id;
beam_hyps.output_ids_tgt[tgt_id_offset + j] = beam_hyps.output_ids_src[src_idx];
prev_id = beam_hyps.parent_ids_src[src_idx];
}
int const tgt_beam_idx = global_batch_idx * k + beam_idx;
beam_hyps.sequence_lengths_tgt[tgt_beam_idx] = beam_hyps.step;
beam_hyps.normed_scores[tgt_beam_idx] = normed_score;
beam_hyps.min_normed_scores[global_batch_idx]
= min(beam_hyps.min_normed_scores[global_batch_idx], beam_hyps.normed_scores[tgt_beam_idx]);
s_val[total.p] = -MAX_T_VAL;
beam_hyps.num_beams[global_batch_idx]++;
}
}
else
{
s_id[selected_beams] = total.p;
s_val[total.p] = -MAX_T_VAL;
selected_beams++;
}
}
__syncthreads();
if (selected_beams >= k)
{
break;
}
}
if (tid < k && is_stop == false)
{
ids[batch_id * k + tid] = topk_tmp_id_buf[batch_id * size + s_id[tid]];
}
}
#define CASE_K_DIV(K, BLOCK_SIZE_1, BLOCK_SIZE_2) \
case K: \
beam_topK_kernel<T, K, BLOCK_SIZE_2><<<batch_size * beam_width, BLOCK_SIZE_2, 0, stream>>>(log_probs, \
topk_tmp_id_buf, topk_tmp_val_buf, finished, sequence_lengths, vocab_size, diversity_rate, \
length_penalty); \
if (K < 10) \
batch_topK_kernel<T, K, BLOCK_SIZE_1> \
<<<batch_size, BLOCK_SIZE_1, 0, stream>>>(topk_tmp_id_buf, topk_tmp_val_buf, ids); \
else \
batch_topK_kernel_v2<T, K, 32><<<batch_size, 32, 0, stream>>>(topk_tmp_id_buf, topk_tmp_val_buf, ids); \
break;
#define CASE_K(K, BLOCK_SIZE_1_, BLOCK_SIZE_2_, BLOCKS_PER_BEAM_) \
case K: \
topk_stage_1_opt3<float, BLOCK_SIZE_1_, BLOCKS_PER_BEAM_> \
<<<batch_size * K * BLOCKS_PER_BEAM_, BLOCK_SIZE_1_, 0, stream>>>(log_probs, temp_log_probs, \
topk_tmp_id_buf, topk_tmp_val_buf, finished, sequence_lengths, beam_width, vocab_size, length_penalty, \
end_ids); \
topk_stage_2_opt3<float, BLOCK_SIZE_2_, BLOCKS_PER_BEAM_> \
<<<batch_size, BLOCK_SIZE_2_, K * sizeof(int), stream>>>( \
topk_tmp_id_buf, topk_tmp_val_buf, ids, *beam_hyps, end_ids, vocab_size, beam_width); \
sync_check_cuda_error(); \
break;
template <typename T>
void invokeTopkBeamSearch(void* workspace, size_t& workspace_size, T* log_probs, int* ids, BeamHypotheses* beam_hyps,
bool const* finished, int const* sequence_lengths, int const batch_size, int const beam_width,
int const vocab_size_padded_, const T diversity_rate, float const length_penalty, int const* end_ids,
cudaStream_t stream)
{
// log_probs: (batch, beam, vocab) cumulative log_probs of beams ending with a
// token.
int const vocab_size = vocab_size_padded_;
// Beam size should be less than or equal to vocab size.
assert(beam_width <= vocab_size);
// Beam search needs the sequence lengths of beams to apply length penalty.
assert(length_penalty == 0.0f || sequence_lengths != nullptr);
int const max_block_per_beam = 8;
int temp_log_probs_buf_size = batch_size * beam_width * vocab_size; // type float
int topk_tmp_ids_buf_size = batch_size * beam_width * beam_width * max_block_per_beam; // type int
int topk_tmp_val_buf_size = batch_size * beam_width * beam_width * max_block_per_beam; // type float
// prevent memory misaligned address
temp_log_probs_buf_size = (int) (ceil(temp_log_probs_buf_size / 4.)) * 4;
topk_tmp_ids_buf_size = (int) (ceil(topk_tmp_ids_buf_size / 4.)) * 4;
topk_tmp_val_buf_size = (int) (ceil(topk_tmp_val_buf_size / 4.)) * 4;
if (workspace == nullptr)
{
workspace_size = sizeof(float) * temp_log_probs_buf_size + sizeof(int) * topk_tmp_ids_buf_size
+ sizeof(float) * topk_tmp_val_buf_size;
return;
}
else
{
T* temp_log_probs = (T*) workspace;
int* topk_tmp_id_buf = (int*) (temp_log_probs + temp_log_probs_buf_size);
T* topk_tmp_val_buf = (T*) (topk_tmp_id_buf + topk_tmp_ids_buf_size);
if (diversity_rate == 0.0f)
{
switch (beam_width)
{
CASE_K(1, 128, 128, 8);
CASE_K(4, 128, 128, 8);
CASE_K(10, 128, 128, 8);
CASE_K(16, 128, 128, 5);
CASE_K(32, 256, 128, 1);
CASE_K(64, 256, 256, 1);
default:
topk_stage_1_opt2_general<T, 128, 1><<<batch_size * beam_width * 1, 128, 0, stream>>>(log_probs,
temp_log_probs, topk_tmp_id_buf, topk_tmp_val_buf, finished, sequence_lengths, beam_width,
vocab_size, length_penalty);
topk_stage_2_opt2_general<T, 128, 1>
<<<batch_size, 128, beam_width * beam_width * 1 * sizeof(float) + beam_width * sizeof(int),
stream>>>(topk_tmp_id_buf, topk_tmp_val_buf, ids, *beam_hyps, end_ids, beam_width, vocab_size);
break;
}
}
else
{
switch (beam_width)
{
CASE_K_DIV(1, 256, 256);
CASE_K_DIV(4, 256, 256);
CASE_K_DIV(16, 256, 64);
CASE_K_DIV(32, 256, 64);
CASE_K_DIV(64, 256, 64);
default: TLLM_THROW("Topk kernel does not support beamwidth = %d \n", beam_width);
}
}
return;
}
}
#undef CASE_K
#undef CASE_K_DIV
template void invokeTopkBeamSearch(void* workspace, size_t& workspace_size, float* log_probs, int* ids,
BeamHypotheses* beam_hyps, bool const* finished, int const* sequence_lengths, int const batch_size,
int const beam_width, int const vocab_size_padded_, float const diversity_rate, float const length_penalty,
int const* end_ids, cudaStream_t stream);
template <typename T>
__global__ void tileEncoderResults(T* tiled_output, int* tiled_sequence_length, T const* output,
int const* sequence_length, const uint32_t batch_size, const uint32_t beam_width, const uint32_t d_model)
{
if (blockIdx.x == 0)
{
for (uint32_t i = threadIdx.x; i < batch_size * beam_width; i += blockDim.x)
{
tiled_sequence_length[i] = sequence_length[i / beam_width];
}
}
int tgt_offset
= blockIdx.x * gridDim.y * gridDim.z * d_model + blockIdx.y * gridDim.z * d_model + blockIdx.z * d_model;
int src_offset = blockIdx.x * gridDim.z * d_model + blockIdx.z * d_model;
for (uint32_t i = threadIdx.x; i < d_model; i += blockDim.x)
{
tiled_output[i + tgt_offset] = output[i + src_offset];
}
}
template <typename T>
void invokeTileEncoderResults(T* tiled_output, int* tiled_sequence_length, T const* output, int const* sequence_length,
const size_t batch_size, const size_t beam_width, const size_t mem_max_seq_len, const size_t d_model,
cudaStream_t stream)
{
// tiled_output: [batch_size, beam_width, mem_max_seq_len, d_model]
// tiled_sequence_length: [batch_size, beam_width]
// output: [batch_size, mem_max_seq_len, d_model]
// sequence_length [batch_size]
dim3 grid(batch_size, beam_width, mem_max_seq_len);
bool is_half2 = (std::is_same<T, half>::value) && (d_model % 2 == 0);
if (is_half2)
{
using T2 = typename TypeConverter<T>::Type; // fp16 to half2, bf16 to bf162
dim3 block(min(512, (int) (d_model / 2)));
tileEncoderResults<T2><<<grid, block, 0, stream>>>((T2*) tiled_output, tiled_sequence_length,
(const T2*) output, sequence_length, batch_size, beam_width, d_model / 2);
}
else
{
dim3 block(min(512, (int) d_model));
tileEncoderResults<T><<<grid, block, 0, stream>>>(
tiled_output, tiled_sequence_length, output, sequence_length, batch_size, beam_width, d_model);
}
}
template void invokeTileEncoderResults(float* tiled_output, int* tiled_sequence_length, float const* output,
int const* sequence_length, const size_t batch_size, const size_t beam_width, const size_t mem_max_seq_len,
const size_t d_model, cudaStream_t stream);
template void invokeTileEncoderResults(half* tiled_output, int* tiled_sequence_length, half const* output,
int const* sequence_length, const size_t batch_size, const size_t beam_width, const size_t mem_max_seq_len,
const size_t d_model, cudaStream_t stream);
template void invokeTileEncoderResults(half2* tiled_output, int* tiled_sequence_length, half2 const* output,
int const* sequence_length, const size_t batch_size, const size_t beam_width, const size_t mem_max_seq_len,
const size_t d_model, cudaStream_t stream);
#ifdef ENABLE_BF16
template void invokeTileEncoderResults(__nv_bfloat16* tiled_output, int* tiled_sequence_length,
__nv_bfloat16 const* output, int const* sequence_length, const size_t batch_size, const size_t beam_width,
const size_t mem_max_seq_len, const size_t d_model, cudaStream_t stream);
#endif
__global__ void insertUnfinishedPath(BeamHypotheses beam_hyps, FinishedState const* finished,
float const* cum_log_probs, int const batch_size, int const beam_width)
{
int const bid = blockIdx.x;
int const tgt_start_idx = beam_hyps.num_beams[bid];
int const max_seq_len{beam_hyps.max_seq_len};
float const length_penalty{beam_hyps.length_penalties == nullptr ? 1.0f : beam_hyps.length_penalties[bid]};
if (beam_hyps.is_done[bid])
{
return;
}
for (int beam_idx = 0; beam_idx < beam_width; beam_idx++)
{
if (threadIdx.x == 0)
{
int const src_beam_idx = bid * beam_width + beam_idx;
int const tgt_beam_idx = bid * beam_width * 2 + beam_idx + tgt_start_idx;
int const last_token_idx = beam_hyps.sequence_lengths_src[src_beam_idx] - 1;
beam_hyps.output_ids_tgt[tgt_beam_idx * max_seq_len + last_token_idx]
= beam_hyps.output_ids_src[src_beam_idx * max_seq_len + last_token_idx];
if (beam_hyps.log_probs != nullptr && beam_hyps.log_probs_src != nullptr)
{
beam_hyps.log_probs[tgt_beam_idx * max_seq_len + last_token_idx]
= beam_hyps.log_probs_src[last_token_idx * batch_size * beam_width + src_beam_idx];
}
int prev_id = beam_hyps.parent_ids_src[src_beam_idx * max_seq_len + last_token_idx];
for (int token_idx = last_token_idx - 1; token_idx >= 0; token_idx--)
{
// output_ids_tgt need to use max_seq_len + 1 because its shape is
// [bs, beam_width, max_seq_len + 1]
beam_hyps.output_ids_tgt[tgt_beam_idx * max_seq_len + token_idx]
= beam_hyps.output_ids_src[bid * beam_width * max_seq_len + prev_id * max_seq_len + token_idx];
if (beam_hyps.log_probs != nullptr && beam_hyps.log_probs_src != nullptr)
{
beam_hyps.log_probs[tgt_beam_idx * max_seq_len + token_idx]
= beam_hyps.log_probs_src[token_idx * batch_size * beam_width + bid * beam_width + prev_id];
}
prev_id = beam_hyps.parent_ids_src[bid * beam_width * max_seq_len + prev_id * max_seq_len + token_idx];
}
beam_hyps.sequence_lengths_tgt[tgt_beam_idx] = last_token_idx + 1;
// TODO huggingface uses total length to normalize the scores, instead of number of generated tokens.
// Check that is it reasonable or not.
beam_hyps.normed_scores[tgt_beam_idx] = apply_length_penalty(cum_log_probs[src_beam_idx],
finished[src_beam_idx].isFinished() ? last_token_idx + 1 : last_token_idx, length_penalty);
beam_hyps.cum_log_probs[tgt_beam_idx] = cum_log_probs[src_beam_idx];
beam_hyps.num_beams[bid]++;
}
}
}
void invokeInsertUnfinishedPath(BeamHypotheses beam_hyps, FinishedState const* finished, float const* cum_log_probs,
int const batch_size, int const beam_width, cudaStream_t stream)
{
insertUnfinishedPath<<<batch_size, 256, 0, stream>>>(beam_hyps, finished, cum_log_probs, batch_size, beam_width);
}
__global__ void copyBatchMajorToGeneralPtr(
void* output_ids_ptr, int* output_ids, int batch_size, int beam_width, int max_seq_len)
{
// output_ids_ptr: batch_size int*, each int* has [beam_width, max_seq_len]
// output_ids: [max_seq_len, batch, beam]
int** output_ids_int_ptr = (int**) output_ids_ptr;
for (int idx = threadIdx.x; idx < beam_width * max_seq_len; idx += blockDim.x)
{
auto const src_step = idx % max_seq_len;
auto const src_beam_idx = idx / max_seq_len;
output_ids_int_ptr[blockIdx.x][idx]
= output_ids[src_step * batch_size * beam_width + blockIdx.x * beam_width + src_beam_idx];
}
}
void invokeCopyBatchMajorToGeneralPtr(
void* output_ids_ptr, int* output_ids, int batch_size, int beam_width, int max_seq_len, cudaStream_t stream)
{
copyBatchMajorToGeneralPtr<<<batch_size, 256, 0, stream>>>(
output_ids_ptr, output_ids, batch_size, beam_width, max_seq_len);
}
__global__ void copyGeneralPtrToBatchMajor(
int* output_ids, void* output_ids_ptr, int batch_size, int beam_width, int max_seq_len)
{
// output_ids_ptr: batch_size int*, each int* has [beam_width, max_seq_len]
// output_ids: [max_seq_len, batch, beam]
int** output_ids_int_ptr = (int**) output_ids_ptr;
for (int idx = threadIdx.x; idx < beam_width * max_seq_len; idx += blockDim.x)
{
auto const tgt_step = idx % max_seq_len;
auto const tgt_beam_idx = idx / max_seq_len;
output_ids[tgt_step * batch_size * beam_width + blockIdx.x * beam_width + tgt_beam_idx]
= output_ids_int_ptr[blockIdx.x][idx];
}
}
void invokeCopyGeneralPtrToBatchMajor(
int* output_ids, void* output_ids_ptr, int batch_size, int beam_width, int max_seq_len, cudaStream_t stream)
{
copyGeneralPtrToBatchMajor<<<batch_size, 256, 0, stream>>>(
output_ids, output_ids_ptr, batch_size, beam_width, max_seq_len);
}
__global__ void SeqlenMajorToBatchMajor(
int* batchMajoredIds, int* seqlenMajorIds, int batch_size, int beam_width, int max_seq_len)
{
for (int idx = blockIdx.x * blockDim.x + threadIdx.x; idx < batch_size * beam_width * max_seq_len;
idx += gridDim.x * blockDim.x)
{
auto tmp_idx{idx};
auto const beam_idx{tmp_idx % beam_width};
tmp_idx = (tmp_idx - beam_idx) / beam_width;
auto const batch_idx{tmp_idx % batch_size};
tmp_idx = (tmp_idx - batch_idx) / batch_size;
auto const seqlen_idx{tmp_idx % max_seq_len};
batchMajoredIds[batch_idx * beam_width * max_seq_len + beam_idx * max_seq_len + seqlen_idx]
= seqlenMajorIds[idx];
}
}
void invokeSeqlenMajorToBatchMajor(
int* batchMajoredIds, int* seqlenMajorIds, int batch_size, int beam_width, int max_seq_len, cudaStream_t stream)
{
SeqlenMajorToBatchMajor<<<batch_size, 256, 0, stream>>>(
batchMajoredIds, seqlenMajorIds, batch_size, beam_width, max_seq_len);
}
} // namespace kernels
} // namespace tensorrt_llm