TensorRT-LLMs/cpp/tensorrt_llm/batch_manager/logitsPostProcessor.cpp

/*
 * SPDX-FileCopyrightText: Copyright (c) 2025 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
 * SPDX-License-Identifier: Apache-2.0
 *
 * 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/batch_manager/logitsPostProcessor.h"

#include "tensorrt_llm/batch_manager/decoderBuffers.h"
#include "tensorrt_llm/batch_manager/llmRequest.h"
#include "tensorrt_llm/batch_manager/runtimeBuffers.h"
#include "tensorrt_llm/common/nvtxUtils.h"
#include "tensorrt_llm/runtime/iTensor.h"

namespace tr = tensorrt_llm::runtime;

namespace tensorrt_llm::batch_manager
{

using TensorPtr = runtime::ITensor::SharedPtr;
using ITensor = runtime::ITensor;
using SizeType32 = tensorrt_llm::runtime::SizeType32;

bool LogitsPostProcessor::operator()(DecoderInputBuffers& inputBuffers, bool replicateLogitsPostProcessor,
    tr::WorldConfig const& worldConfig, CudaStreamPtr const& stream,
    std::optional<LogitsPostProcessorBatched> const& logitsPostProcessorBatched) const
{
    TLLM_LOG_TRACE("%s start", __PRETTY_FUNCTION__);
    NVTX3_SCOPED_RANGE(LogitsPostProcessor);

    // Arguments for batched processor
    std::vector<LlmRequest::RequestIdType> reqIdsVec;
    std::vector<LlmRequest::TensorPtr> logitsVec;
    std::vector<std::reference_wrapper<LlmRequest::BeamTokens const>> beamTokensVec;
    std::vector<std::optional<LlmRequest::RequestIdType>> clientIdsVec;

    bool logitsPostProcessorIsApplied = false;
    for (size_t batchIdx = 0; batchIdx < inputBuffers.decoderRequests.size(); ++batchIdx)
    {
        auto const& llmReq = inputBuffers.decoderRequests.at(batchIdx);
        auto& logits = inputBuffers.logits.at(batchIdx);

        // Invoke non-batched processor or collect arguments for batched processor
        if (llmReq->mLogitsPostProcessor)
        {
            logitsPostProcessorIsApplied = true;
            if (replicateLogitsPostProcessor || worldConfig.isFirstTensorParallelRank())
            {
                (*llmReq->mLogitsPostProcessor)(
                    llmReq->mRequestId, logits, llmReq->getTokens(), stream, llmReq->mClientId);
            }
        }
        else if (llmReq->mApplyLogitsPostProcessorBatched)
        {
            reqIdsVec.push_back(llmReq->mRequestId);
            logitsVec.push_back(logits);
            beamTokensVec.emplace_back(llmReq->getTokens());
            clientIdsVec.push_back(llmReq->mClientId);
        }
    }

    // Invoke batched processor
    if (!reqIdsVec.empty())
    {
        logitsPostProcessorIsApplied = true;
        if (replicateLogitsPostProcessor || worldConfig.isFirstTensorParallelRank())
        {
            (*logitsPostProcessorBatched)(reqIdsVec, logitsVec, beamTokensVec, stream, clientIdsVec);
        }
    }

    TLLM_LOG_TRACE("%s stop", __PRETTY_FUNCTION__);

    return logitsPostProcessorIsApplied;
}

} // namespace tensorrt_llm::batch_manager