TensorRT-LLMs/cpp/tensorrt_llm/thop/helixPostProcessOp.cpp
Matthias Jouanneaux d0f107e4dd
[TRTLLM-5966][feat] Helix: add full MLA support for Helix (#8104)
Signed-off-by: Matthias Jouanneaux <mjoux@nvidia.com>
2025-11-04 09:06:58 +08:00

111 lines
4.5 KiB
C++

/*
* Copyright (c) 2025, 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.
*/
#include "tensorrt_llm/common/cudaUtils.h"
#include "tensorrt_llm/kernels/helixKernels.h"
#include "tensorrt_llm/thop/thUtils.h"
#include <cuda_bf16.h>
#include <cuda_fp16.h>
namespace torch_ext
{
torch::Tensor helix_post_process(torch::Tensor const& gathered_o, torch::Tensor const& gathered_stats, double scale)
{
CHECK_TH_CUDA(gathered_o);
CHECK_CONTIGUOUS(gathered_o);
CHECK_TH_CUDA(gathered_stats);
CHECK_CONTIGUOUS(gathered_stats);
TORCH_CHECK(gathered_o.dim() == 3, "gathered_o must be 3D tensor [cp_size, num_tokens, num_heads * kv_lora_rank]");
TORCH_CHECK(gathered_stats.dim() == 4, "gathered_stats must be 4D tensor [cp_size, num_tokens, num_heads, 2]");
auto const cp_size = gathered_stats.sizes()[0];
auto const num_tokens = gathered_stats.sizes()[1];
auto const num_heads = gathered_stats.sizes()[2];
TORCH_CHECK(gathered_o.sizes()[2] % num_heads == 0, "last dimension of gathered_o must be divisible by num_heads");
auto const kv_lora_rank = gathered_o.sizes()[2] / num_heads;
// check remaining input tensor dimensions
TORCH_CHECK(gathered_o.sizes()[0] == cp_size, "gathered_o first dimension must match cp_size");
TORCH_CHECK(gathered_o.sizes()[1] == num_tokens, "gathered_o second dimension must match num_tokens");
TORCH_CHECK(gathered_o.sizes()[2] == num_heads * kv_lora_rank,
"gathered_o third dimension must match num_heads * kv_lora_rank");
TORCH_CHECK(gathered_stats.sizes()[3] == 2, "gathered_stats fourth dimension must be 2");
// Check data types
TORCH_CHECK(
gathered_o.scalar_type() == at::ScalarType::Half || gathered_o.scalar_type() == at::ScalarType::BFloat16,
"gathered_o must be half or bfloat16");
TORCH_CHECK(gathered_stats.scalar_type() == at::ScalarType::Float, "gathered_stats must be float32");
// Check alignment requirements for gathered_o (16-byte aligned for async memcpy)
TORCH_CHECK(reinterpret_cast<uintptr_t>(gathered_o.data_ptr()) % 16 == 0, "gathered_o must be 16-byte aligned");
// Check that kv_lora_rank * sizeof(data_type) is a multiple of 16
size_t data_type_size = torch::elementSize(gathered_o.scalar_type());
TORCH_CHECK((kv_lora_rank * data_type_size) % 16 == 0, "kv_lora_rank * sizeof(data_type) must be a multiple of 16");
// Create output tensor
std::vector<int64_t> output_shape = {num_tokens, num_heads * kv_lora_rank};
torch::Tensor output = torch::empty(output_shape, gathered_o.options());
// Get CUDA stream
auto stream = at::cuda::getCurrentCUDAStream(gathered_o.get_device());
#define CALL_CPP_OP(T) \
tensorrt_llm::kernels::HelixPostProcParams<T> params{reinterpret_cast<T*>(output.mutable_data_ptr()), \
reinterpret_cast<T const*>(gathered_o.data_ptr()), reinterpret_cast<float2 const*>(gathered_stats.data_ptr()), \
static_cast<int>(cp_size), static_cast<int>(num_tokens), static_cast<int>(num_heads), \
static_cast<int>(kv_lora_rank)}; \
tensorrt_llm::kernels::helixPostProcess(params, stream);
if (gathered_o.scalar_type() == at::ScalarType::Half)
{
CALL_CPP_OP(__half);
}
else if (gathered_o.scalar_type() == at::ScalarType::BFloat16)
{
#ifdef ENABLE_BF16
CALL_CPP_OP(__nv_bfloat16);
#else
TLLM_THROW("BFloat16 must be enabled to use helix_post_process with bf16 tensors.");
#endif
}
if (scale != 1.0)
{
output *= scale;
}
return output;
}
TORCH_LIBRARY_FRAGMENT(trtllm, m)
{
m.def("helix_post_process(Tensor gathered_o, Tensor gathered_stats, float scale) -> Tensor");
}
TORCH_LIBRARY_IMPL(trtllm, CUDA, m)
{
m.impl("helix_post_process", helix_post_process);
}
} // namespace torch_ext