dxvk/src/dxvk/dxvk_fence.cpp

#include "dxvk_device.h"
#include "dxvk_fence.h"

namespace dxvk {

  DxvkFence::DxvkFence(
          DxvkDevice*           device,
    const DxvkFenceCreateInfo&  info)
  : m_vkd(device->vkd()), m_info(info) {
    VkSemaphoreTypeCreateInfo typeInfo = { VK_STRUCTURE_TYPE_SEMAPHORE_TYPE_CREATE_INFO };
    typeInfo.semaphoreType = VK_SEMAPHORE_TYPE_TIMELINE;
    typeInfo.initialValue = info.initialValue;
    
    VkExportSemaphoreCreateInfo exportInfo = { VK_STRUCTURE_TYPE_EXPORT_SEMAPHORE_CREATE_INFO };
    exportInfo.handleTypes = info.sharedType;

    VkExternalSemaphoreFeatureFlags externalFeatures = 0;

    if (info.sharedType != VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_FLAG_BITS_MAX_ENUM) {
      auto vki = device->adapter()->vki();

      VkPhysicalDeviceExternalSemaphoreInfo externalInfo = { VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXTERNAL_SEMAPHORE_INFO, &typeInfo };
      externalInfo.handleType = info.sharedType;

      VkExternalSemaphoreProperties externalProperties = { };
      vki->vkGetPhysicalDeviceExternalSemaphoreProperties(
        device->adapter()->handle(), &externalInfo, &externalProperties);

      externalFeatures = externalProperties.externalSemaphoreFeatures;

      if (externalFeatures & VK_EXTERNAL_SEMAPHORE_FEATURE_EXPORTABLE_BIT)
        typeInfo.pNext = &exportInfo;
      else
        Logger::warn(str::format("Exporting semaphores of type ", info.sharedType, " not supported by device"));
    }

    VkSemaphoreCreateInfo semaphoreInfo = { VK_STRUCTURE_TYPE_SEMAPHORE_CREATE_INFO, &typeInfo };

    VkResult vr = m_vkd->vkCreateSemaphore(m_vkd->device(),
      &semaphoreInfo, nullptr, &m_semaphore);

    if (vr != VK_SUCCESS)
      throw DxvkError("Failed to create timeline semaphore");

    if (info.sharedHandle != INVALID_HANDLE_VALUE) {
      if (externalFeatures & VK_EXTERNAL_SEMAPHORE_FEATURE_IMPORTABLE_BIT) {
        VkImportSemaphoreWin32HandleInfoKHR importInfo = { VK_STRUCTURE_TYPE_IMPORT_SEMAPHORE_WIN32_HANDLE_INFO_KHR };
        importInfo.semaphore = m_semaphore;
        importInfo.handleType = info.sharedType;
        importInfo.handle = info.sharedHandle;

        vr = m_vkd->vkImportSemaphoreWin32HandleKHR(m_vkd->device(), &importInfo);
        if (vr != VK_SUCCESS)
          throw DxvkError("Failed to import timeline semaphore");
      } else {
        Logger::warn(str::format("Importing semaphores of type ", info.sharedType, " not supported by device"));
      }
    }
  }


  DxvkFence::~DxvkFence() {
    if (m_thread.joinable()) {
      {
        std::unique_lock<dxvk::mutex> lock(m_mutex);
        m_running = false;
        m_condVar.notify_one();
      }
      m_thread.join();
    }
    m_vkd->vkDestroySemaphore(m_vkd->device(), m_semaphore, nullptr);
  }


  void DxvkFence::enqueueWait(uint64_t value, DxvkFenceEvent&& event) {
    if (value > getValue()) {
      std::unique_lock<dxvk::mutex> lock(m_mutex);
      m_queue.emplace(value, std::move(event));

      if (!m_running) {
        m_running = true;
        m_thread = dxvk::thread([this] { run(); });
      } else {
        m_condVar.notify_one();
      }
      lock.unlock();
    } else {
      event();
    }
  }

  void DxvkFence::wait(uint64_t value) {
    VkSemaphoreWaitInfo waitInfo = { VK_STRUCTURE_TYPE_SEMAPHORE_WAIT_INFO };
    waitInfo.semaphoreCount = 1;
    waitInfo.pSemaphores = &m_semaphore;
    waitInfo.pValues = &value;
    VkResult vr = m_vkd->vkWaitSemaphores(
      m_vkd->device(), &waitInfo, ~0ull);

    if (vr != VK_SUCCESS) {
      Logger::err(str::format("Failed to wait for semaphore: ", vr));
    }
  }

  void DxvkFence::run() {
    uint64_t value = 0ull;

    VkSemaphoreWaitInfo waitInfo = { VK_STRUCTURE_TYPE_SEMAPHORE_WAIT_INFO };
    waitInfo.semaphoreCount = 1;
    waitInfo.pSemaphores = &m_semaphore;
    waitInfo.pValues = &value;

    while (true) {
      std::unique_lock<dxvk::mutex> lock(m_mutex);

      m_condVar.wait(lock, [&]() { return !m_queue.empty() || !m_running; });

      // Query actual semaphore value and start from there, so that
      // we can skip over large increments in the semaphore value
      VkResult vr = m_vkd->vkGetSemaphoreCounterValue(m_vkd->device(), m_semaphore, &value);

      if (vr != VK_SUCCESS) {
        Logger::err(str::format("Failed to query semaphore value: ", vr));
        return;
      }

      // Signal all enqueued events whose value is not greater than
      // the current semaphore value
      while (!m_queue.empty() && m_queue.top().value <= value) {
        m_queue.top().event();
        m_queue.pop();
      }

      if (!m_running)
        return;

      if (m_queue.empty())
        continue;

      lock.unlock();

      // Wait for the semaphore to be singaled again and update state.
      // The timeout is unfortunate, but we can't always know when a
      // signal operation has been recorded, and the alternative would
      // be to create a teardown semaphore and use WAIT_ANY, which may
      // be fall back to a busy-wait loop on some drivers.
      value += 1;

      vr = m_vkd->vkWaitSemaphores(
        m_vkd->device(), &waitInfo, 10'000'000ull);

      if (vr != VK_SUCCESS && vr != VK_TIMEOUT) {
        Logger::err(str::format("Failed to wait for semaphore: ", vr));
        return;
      }
    }
  }

  uint64_t DxvkFence::getValue() {
    uint64_t value = 0;
    VkResult vr = m_vkd->vkGetSemaphoreCounterValue(m_vkd->device(), m_semaphore, &value);
    if (vr != VK_SUCCESS) {
      Logger::err(str::format("Failed to query semaphore value: ", vr));
    }
    return value;
  }

  HANDLE DxvkFence::sharedHandle() const {
    if (m_info.sharedType == VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_FLAG_BITS_MAX_ENUM)
      return INVALID_HANDLE_VALUE;

    VkSemaphoreGetWin32HandleInfoKHR win32HandleInfo = { VK_STRUCTURE_TYPE_SEMAPHORE_GET_WIN32_HANDLE_INFO_KHR };
    win32HandleInfo.semaphore = m_semaphore;
    win32HandleInfo.handleType = m_info.sharedType;

    HANDLE sharedHandle = INVALID_HANDLE_VALUE;
    VkResult vr = m_vkd->vkGetSemaphoreWin32HandleKHR(m_vkd->device(), &win32HandleInfo, &sharedHandle);

    if (vr != VK_SUCCESS)
      Logger::err(str::format("Failed to get semaphore handle: ", vr));

    return sharedHandle;
  }
}