producer.hpp

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/*
 *   Copyright 2025 Huawei Technologies Co., Ltd.
 *
 * 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.
 */
 
#pragma once
 
#include <hicr/core/definitions.hpp>
#include <hicr/core/exceptions.hpp>
#include <hicr/frontends/channel/fixedSize/base.hpp>
#include <utility>
 
namespace HiCR::channel::fixedSize::SPSC
{
 
class Producer : public fixedSize::Base
{
  private:
 
  const std::shared_ptr<GlobalMemorySlot> _tokenBuffer;
 
  /*
   * Global Memory slot pointing to the consumer coordination buffer
   */
  const std::shared_ptr<GlobalMemorySlot> _consumerCoordinationBuffer;
 
  public:
 
  Producer(CommunicationManager                   &coordinationCommunicationManager,
           CommunicationManager                   &payloadCommunicationManager,
           std::shared_ptr<GlobalMemorySlot>       tokenBuffer,
           const std::shared_ptr<LocalMemorySlot> &internalCoordinationBuffer,
           std::shared_ptr<GlobalMemorySlot>       consumerCoordinationBuffer,
           const size_t                            tokenSize,
           const size_t                            capacity)
    : fixedSize::Base(coordinationCommunicationManager, payloadCommunicationManager, internalCoordinationBuffer, tokenSize, capacity),
      _tokenBuffer(std::move(tokenBuffer)),
      _consumerCoordinationBuffer(std::move(consumerCoordinationBuffer))
  {}
 
  ~Producer() = default;
 
  __INLINE__ void push(const std::shared_ptr<LocalMemorySlot> &sourceSlot, const size_t n = 1)
  {
    // Make sure source slot is big enough to satisfy the operation
    auto requiredBufferSize = getTokenSize() * n;
    auto providedBufferSize = sourceSlot->getSize();
    if (providedBufferSize < requiredBufferSize)
      HICR_THROW_LOGIC("Attempting to push with a source buffer size (%lu) smaller than the required size (Token Size (%lu) x n (%lu) = %lu).\n",
                       providedBufferSize,
                       getTokenSize(),
                       n,
                       requiredBufferSize);
 
    // Updating channel depth
    updateDepth();
 
    // Calculating current channel depth
    auto curDepth = getCircularBuffer()->getDepth();
 
    // If the exchange buffer does not have n free slots, reject the operation
    if (curDepth + n > getCircularBuffer()->getCapacity())
      HICR_THROW_RUNTIME(
        "Attempting to push with (%lu) tokens while the channel has (%lu) tokens and this would exceed capacity (%lu).\n", n, curDepth, getCircularBuffer()->getCapacity());
 
    auto payloadCommunicationManager = getPayloadCommunicationManager();
    for (size_t i = 0; i < n; i++)
    {
      // Copying with source increasing offset per token
      payloadCommunicationManager->memcpy(_tokenBuffer,                                            /* destination */
                                          getTokenSize() * getCircularBuffer()->getHeadPosition(), /* dst_offset */
                                          sourceSlot,                                              /* source */
                                          i * getTokenSize(),                                      /* src_offset */
                                          getTokenSize());                                         /* size */
    }
    payloadCommunicationManager->fence(sourceSlot, n, 0);
 
    // read possibly slightly outdated depth here (will be updated next round)
    getCircularBuffer()->advanceHead(n);
 
    /*
     * In this implementation of producer-consumer, the producer
     * actively and in a one-sided manner updates the depth at the consumer.
     * This implementation has some advantages for MPSC implementations
     * on top of SPSC
     */
    auto coordinationCommunicationManager = getCoordinationCommunicationManager();
    coordinationCommunicationManager->memcpy(_consumerCoordinationBuffer,
                                             _HICR_CHANNEL_HEAD_ADVANCE_COUNT_IDX * sizeof(size_t),
                                             getCoordinationBuffer(),
                                             _HICR_CHANNEL_HEAD_ADVANCE_COUNT_IDX * sizeof(size_t),
                                             sizeof(size_t));
    coordinationCommunicationManager->fence(getCoordinationBuffer(), 1, 0);
  }
 
  __INLINE__ void updateDepth()
  {
    // Perform a non-blocking check of the coordination and token buffers, to see and/or notify if there are new messages
    getCoordinationCommunicationManager()->queryMemorySlotUpdates(getCoordinationBuffer());
  }
};
 
} // namespace HiCR::channel::fixedSize::SPSC