vllm/csrc/cpu/pos_encoding.cpp

199 lines
7.5 KiB
C++

#include "cpu_types.hpp"
namespace {
template <typename scalar_t>
void rotary_embedding_impl(
const int64_t* __restrict__ positions, // [batch_size, seq_len] or
// [num_tokens]
scalar_t* __restrict__ query, /// [batch_size, seq_len, num_heads,
/// head_size] or [num_tokens, num_heads,
/// head_size]
scalar_t* __restrict__ key, // [batch_size, seq_len, num_kv_heads,
// head_size] or [num_tokens, num_kv_heads,
// head_size]
const scalar_t* __restrict__ cos_sin_cache, // [max_position, 2, rot_dim //
// 2]
const int rot_dim, const int64_t query_stride, const int64_t key_stride,
const int num_heads, const int num_kv_heads, const int head_size,
const int num_tokens) {
using scalar_vec_t = vec_op::vec_t<scalar_t>;
constexpr int VEC_ELEM_NUM = scalar_vec_t::get_elem_num();
const int embed_dim = rot_dim / 2;
TORCH_CHECK(embed_dim % VEC_ELEM_NUM == 0);
#pragma omp parallel for
for (int token_idx = 0; token_idx < num_tokens; ++token_idx) {
int64_t pos = positions[token_idx];
const scalar_t* cache_ptr = cos_sin_cache + pos * rot_dim;
for (int i = 0; i < num_heads; ++i) {
const int head_idx = i;
const int64_t token_head =
token_idx * query_stride + head_idx * head_size;
for (int j = 0; j < embed_dim; j += VEC_ELEM_NUM) {
const int rot_offset = j;
const int x_index = rot_offset;
const int y_index = embed_dim + rot_offset;
const int64_t out_x = token_head + x_index;
const int64_t out_y = token_head + y_index;
const scalar_vec_t cos(cache_ptr + x_index);
const scalar_vec_t sin(cache_ptr + y_index);
const scalar_vec_t q_x(query + out_x);
const scalar_vec_t q_y(query + out_y);
vec_op::FP32Vec8 fp32_cos(cos);
vec_op::FP32Vec8 fp32_sin(sin);
vec_op::FP32Vec8 fp32_q_x(q_x);
vec_op::FP32Vec8 fp32_q_y(q_y);
auto out1 = fp32_q_x * fp32_cos - fp32_q_y * fp32_sin;
scalar_vec_t(out1).save(query + out_x);
auto out2 = fp32_q_y * fp32_cos + fp32_q_x * fp32_sin;
scalar_vec_t(out2).save(query + out_y);
}
}
for (int i = 0; i < num_kv_heads; ++i) {
const int head_idx = i;
const int64_t token_head = token_idx * key_stride + head_idx * head_size;
for (int j = 0; j < embed_dim; j += VEC_ELEM_NUM) {
const int rot_offset = j;
const int x_index = rot_offset;
const int y_index = embed_dim + rot_offset;
const int64_t out_x = token_head + x_index;
const int64_t out_y = token_head + y_index;
const scalar_vec_t cos(cache_ptr + x_index);
const scalar_vec_t sin(cache_ptr + y_index);
const scalar_vec_t k_x(key + out_x);
const scalar_vec_t k_y(key + out_y);
vec_op::FP32Vec8 fp32_cos(cos);
vec_op::FP32Vec8 fp32_sin(sin);
vec_op::FP32Vec8 fp32_k_x(k_x);
vec_op::FP32Vec8 fp32_k_y(k_y);
auto out1 = fp32_k_x * fp32_cos - fp32_k_y * fp32_sin;
scalar_vec_t(out1).save(key + out_x);
auto out2 = fp32_k_y * fp32_cos + fp32_k_x * fp32_sin;
scalar_vec_t(out2).save(key + out_y);
}
}
}
}
template <typename scalar_t>
void rotary_embedding_gptj_impl(
const int64_t* __restrict__ positions, // [batch_size, seq_len] or
// [num_tokens]
scalar_t* __restrict__ query, /// [batch_size, seq_len, num_heads,
/// head_size] or [num_tokens, num_heads,
/// head_size]
scalar_t* __restrict__ key, // [batch_size, seq_len, num_kv_heads,
// head_size] or [num_tokens, num_kv_heads,
// head_size]
const scalar_t* __restrict__ cos_sin_cache, // [max_position, 2, rot_dim //
// 2]
const int rot_dim, const int64_t query_stride, const int64_t key_stride,
const int num_heads, const int num_kv_heads, const int head_size,
const int num_tokens) {
const int embed_dim = rot_dim / 2;
#pragma omp parallel for collapse(2)
for (int token_idx = 0; token_idx < num_tokens; ++token_idx) {
for (int i = 0; i < num_heads; ++i) {
int64_t pos = positions[token_idx];
const scalar_t* cache_ptr = cos_sin_cache + pos * rot_dim;
const scalar_t* cos_cache_ptr = cache_ptr;
const scalar_t* sin_cache_ptr = cache_ptr + embed_dim;
const int head_idx = i;
const int64_t token_head =
token_idx * query_stride + head_idx * head_size;
scalar_t* head_query = token_head + query;
for (int j = 0; j < embed_dim; j += 1) {
const int rot_offset = j;
const int x_index = 2 * rot_offset;
const int y_index = 2 * rot_offset + 1;
const float cos = cos_cache_ptr[rot_offset];
const float sin = sin_cache_ptr[rot_offset];
const float x = head_query[x_index];
const float y = head_query[y_index];
head_query[x_index] = x * cos - y * sin;
head_query[y_index] = y * cos + x * sin;
}
}
}
#pragma omp parallel for collapse(2)
for (int token_idx = 0; token_idx < num_tokens; ++token_idx) {
for (int i = 0; i < num_kv_heads; ++i) {
int64_t pos = positions[token_idx];
const scalar_t* cache_ptr = cos_sin_cache + pos * rot_dim;
const scalar_t* cos_cache_ptr = cache_ptr;
const scalar_t* sin_cache_ptr = cache_ptr + embed_dim;
const int head_idx = i;
const int64_t token_head = token_idx * key_stride + head_idx * head_size;
scalar_t* head_key = key + token_head;
for (int j = 0; j < embed_dim; j += 1) {
const int rot_offset = j;
const int x_index = 2 * rot_offset;
const int y_index = 2 * rot_offset + 1;
const float cos = cos_cache_ptr[rot_offset];
const float sin = sin_cache_ptr[rot_offset];
const float x = head_key[x_index];
const float y = head_key[y_index];
head_key[x_index] = x * cos - y * sin;
head_key[y_index] = y * cos + x * sin;
}
}
}
}
}; // namespace
void rotary_embedding(torch::Tensor& positions, torch::Tensor& query,
torch::Tensor& key, int head_size,
torch::Tensor& cos_sin_cache, bool is_neox) {
int num_tokens = query.numel() / query.size(-1);
int rot_dim = cos_sin_cache.size(1);
int num_heads = query.size(-1) / head_size;
int num_kv_heads = key.size(-1) / head_size;
int64_t key_stride = key.stride(-2);
int64_t query_stride = query.stride(-2);
VLLM_DISPATCH_FLOATING_TYPES(
query.scalar_type(), "rotary_embedding_impl", [&] {
CPU_KERNEL_GUARD_IN(rotary_embedding_impl)
if (is_neox) {
rotary_embedding_impl(
positions.data_ptr<int64_t>(), query.data_ptr<scalar_t>(),
key.data_ptr<scalar_t>(), cos_sin_cache.data_ptr<scalar_t>(),
rot_dim, query_stride, key_stride, num_heads, num_kv_heads,
head_size, num_tokens);
} else {
rotary_embedding_gptj_impl(
positions.data_ptr<int64_t>(), query.data_ptr<scalar_t>(),
key.data_ptr<scalar_t>(), cos_sin_cache.data_ptr<scalar_t>(),
rot_dim, query_stride, key_stride, num_heads, num_kv_heads,
head_size, num_tokens);
}
CPU_KERNEL_GUARD_OUT(rotary_embedding_impl)
});
}