vllm/csrc/cpu/cache.cpp
Thien Tran 4f044b1d67
[Kernel][CPU] CPU MLA (#14744)
Signed-off-by: Thien Tran <gau.nernst@yahoo.com.sg>
2025-03-25 09:34:59 +00:00

215 lines
8.8 KiB
C++

#include <map>
#include <vector>
#include "cpu_types.hpp"
#if defined(__x86_64__)
#define DISPATCH_MACRO VLLM_DISPATCH_FLOATING_TYPES_WITH_E5M2
#else
#define DISPATCH_MACRO VLLM_DISPATCH_FLOATING_TYPES
#endif
namespace {
template <typename scalar_t>
void copy_blocks_cpu_impl(std::vector<torch::Tensor> const& key_caches,
std::vector<torch::Tensor> const& value_caches,
const torch::Tensor& mapping_pairs,
const int element_num_per_block,
const int layer_num) {
const size_t pair_num = mapping_pairs.size(0);
const size_t block_bytes = sizeof(scalar_t) * element_num_per_block;
#pragma omp parallel for collapse(2)
for (int layer = 0; layer < layer_num; ++layer) {
for (size_t pair = 0; pair < pair_num; ++pair) {
int64_t source_offset =
element_num_per_block * mapping_pairs[pair][0].item<int64_t>();
int64_t target_offset =
element_num_per_block * mapping_pairs[pair][1].item<int64_t>();
scalar_t* key_cache_ptr = key_caches[layer].data_ptr<scalar_t>();
scalar_t* source_ptr = key_cache_ptr + source_offset;
scalar_t* target_ptr = key_cache_ptr + target_offset;
std::memcpy(target_ptr, source_ptr, block_bytes);
scalar_t* value_cache_ptr = value_caches[layer].data_ptr<scalar_t>();
source_ptr = value_cache_ptr + source_offset;
target_ptr = value_cache_ptr + target_offset;
std::memcpy(target_ptr, source_ptr, block_bytes);
}
}
}
template <typename scalar_t>
void reshape_and_cache_cpu_impl(
const scalar_t* __restrict__ key, const scalar_t* __restrict__ value,
scalar_t* __restrict__ key_cache, scalar_t* __restrict__ value_cache,
const int64_t* __restrict__ slot_mapping, const int num_tokens,
const int key_stride, const int value_stride, const int num_heads,
const int head_size, const int block_size, const int x) {
const int block_elem_num = num_heads * head_size * block_size;
#pragma omp parallel for collapse(2)
for (int token_idx = 0; token_idx < num_tokens; ++token_idx) {
for (int head_idx = 0; head_idx < num_heads; ++head_idx) {
const int64_t slot_idx = slot_mapping[token_idx];
if (slot_idx >= 0) {
int src_key_head_idx = token_idx * key_stride + head_idx * head_size;
int src_value_head_idx =
token_idx * value_stride + head_idx * head_size;
const scalar_t* src_key_head_ptr = key + src_key_head_idx;
const scalar_t* src_value_head_ptr = value + src_value_head_idx;
const int64_t block_index = slot_idx / block_size;
const int64_t block_offset = slot_idx % block_size;
scalar_t* target_key_head_ptr = key_cache +
block_elem_num * block_index +
head_idx * block_size * head_size;
scalar_t* target_value_head_ptr = value_cache +
block_elem_num * block_index +
head_idx * block_size * head_size;
for (int src_key_idx = 0; src_key_idx < head_size; src_key_idx += x) {
const int64_t target_offset =
src_key_idx * block_size + block_offset * x;
for (int i = 0; i < x; ++i) {
target_key_head_ptr[target_offset + i] =
src_key_head_ptr[src_key_idx + i];
}
}
for (int src_value_idx = 0; src_value_idx < head_size;
++src_value_idx) {
const int64_t target_offset =
src_value_idx * block_size + block_offset;
target_value_head_ptr[target_offset] =
src_value_head_ptr[src_value_idx];
}
}
}
}
}
}; // namespace
template <typename scalar_t>
void concat_and_cache_mla_cpu_impl(
const scalar_t* __restrict__ kv_c, // [num_tokens, kv_lora_rank]
const scalar_t* __restrict__ k_pe, // [num_tokens, pe_dim]
scalar_t* __restrict__ kv_cache, // [num_blocks, block_size, (kv_lora_rank
// + pe_dim)]
const int64_t* __restrict__ slot_mapping, // [num_tokens]
const int num_tokens, //
const int block_stride, //
const int entry_stride, //
const int kv_c_stride, //
const int k_pe_stride, //
const int kv_lora_rank, //
const int pe_dim, //
const int block_size //
) {
#pragma omp parallel for
for (int token_idx = 0; token_idx < num_tokens; ++token_idx) {
const int64_t slot_idx = slot_mapping[token_idx];
// NOTE: slot_idx can be -1 if the token is padded
if (slot_idx < 0) {
continue;
}
const int64_t block_idx = slot_idx / block_size;
const int64_t block_offset = slot_idx % block_size;
auto copy = [&](const scalar_t* __restrict__ src,
scalar_t* __restrict__ dst, int src_stride, int dst_stride,
int size, int offset) {
for (int i = 0; i < size; i++) {
const int64_t src_idx = token_idx * src_stride + i;
const int64_t dst_idx =
block_idx * block_stride + block_offset * entry_stride + i + offset;
dst[dst_idx] = src[src_idx];
}
};
copy(kv_c, kv_cache, kv_c_stride, block_stride, kv_lora_rank, 0);
copy(k_pe, kv_cache, k_pe_stride, block_stride, pe_dim, kv_lora_rank);
}
}
// Note: the key_caches and value_caches vectors are constant but
// not the Tensors they contain. The vectors need to be const refs
// in order to satisfy pytorch's C++ operator registration code.
void copy_blocks(std::vector<torch::Tensor> const& key_caches,
std::vector<torch::Tensor> const& value_caches,
const torch::Tensor& block_mapping) {
unsigned num_layers = key_caches.size();
TORCH_CHECK(num_layers == value_caches.size());
if (num_layers == 0) {
return;
}
const int element_num_per_block = key_caches[0][0].numel();
DISPATCH_MACRO(key_caches[0].scalar_type(), "copy_blocks_cpu_impl", [&] {
CPU_KERNEL_GUARD_IN(copy_blocks_cpu_impl)
copy_blocks_cpu_impl<scalar_t>(key_caches, value_caches, block_mapping,
element_num_per_block, num_layers);
CPU_KERNEL_GUARD_OUT(copy_blocks_cpu_impl)
});
}
void reshape_and_cache(torch::Tensor& key, torch::Tensor& value,
torch::Tensor& key_cache, torch::Tensor& value_cache,
torch::Tensor& slot_mapping,
const std::string& kv_cache_dtype,
torch::Tensor& k_scale, torch::Tensor& v_scale) {
int num_tokens = key.size(0);
int num_heads = key.size(1);
int head_size = key.size(2);
int block_size = key_cache.size(3);
int x = key_cache.size(4);
int key_stride = key.stride(0);
int value_stride = value.stride(0);
DISPATCH_MACRO(key.scalar_type(), "reshape_and_cache_cpu_impl", [&] {
CPU_KERNEL_GUARD_IN(reshape_and_cache_cpu_impl)
reshape_and_cache_cpu_impl<scalar_t>(
key.data_ptr<scalar_t>(), value.data_ptr<scalar_t>(),
key_cache.data_ptr<scalar_t>(), value_cache.data_ptr<scalar_t>(),
slot_mapping.data_ptr<int64_t>(), num_tokens, key_stride, value_stride,
num_heads, head_size, block_size, x);
CPU_KERNEL_GUARD_OUT(reshape_and_cache_cpu_impl)
});
}
void concat_and_cache_mla(
torch::Tensor& kv_c, // [num_tokens, kv_lora_rank]
torch::Tensor& k_pe, // [num_tokens, pe_dim]
torch::Tensor& kv_cache, // [num_blocks, block_size, (kv_lora_rank +
// pe_dim)]
torch::Tensor& slot_mapping, // [num_tokens] or [num_actual_tokens]
const std::string& kv_cache_dtype, torch::Tensor& scale) {
int num_tokens = slot_mapping.size(0);
int kv_lora_rank = kv_c.size(1);
int pe_dim = k_pe.size(1);
int block_size = kv_cache.size(1);
TORCH_CHECK(kv_cache.size(2) == kv_lora_rank + pe_dim);
TORCH_CHECK(kv_cache_dtype != "fp8");
int kv_c_stride = kv_c.stride(0);
int k_pe_stride = k_pe.stride(0);
int block_stride = kv_cache.stride(0);
int entry_stride = kv_cache.stride(1);
VLLM_DISPATCH_FLOATING_TYPES(
kv_c.scalar_type(), "concat_and_cache_mla_cpu_impl", [&] {
CPU_KERNEL_GUARD_IN(concat_and_cache_mla_cpu_impl)
concat_and_cache_mla_cpu_impl<scalar_t>(
kv_c.data_ptr<scalar_t>(), k_pe.data_ptr<scalar_t>(),
kv_cache.data_ptr<scalar_t>(), slot_mapping.data_ptr<int64_t>(),
num_tokens, block_stride, entry_stride, kv_c_stride, k_pe_stride,
kv_lora_rank, pe_dim, block_size);
CPU_KERNEL_GUARD_OUT(concat_and_cache_mla_cpu_impl)
});
}
void swap_blocks(torch::Tensor& src, torch::Tensor& dst,
const torch::Tensor& block_mapping) {
TORCH_CHECK(false, "swap_blocks is unsupported on CPU.")
}