58b0ae84b5
This reworks how host<->device synchronization works on the Vulkan backend. Instead of "protecting" resources with a fence and signalling these as free when the fence is known to be signalled by the host GPU, use timeline semaphores. Vulkan timeline semaphores allow use to work on a subset of D3D12 fences. As far as we are concerned, timeline semaphores are a value set by the host or the device that can be waited by either of them. Taking advantange of this, we can have a monolithically increasing atomic value for each submission to the graphics queue. Instead of protecting resources with a fence, we simply store the current logical tick (the atomic value stored in CPU memory). When we want to know if a resource is free, it can be compared to the current GPU tick. This greatly simplifies resource management code and the free status of resources should have less false negatives. To workaround bugs in validation layers, when these are attached there's a thread waiting for timeline semaphores.
56 lines
1.7 KiB
C++
56 lines
1.7 KiB
C++
// Copyright 2020 yuzu Emulator Project
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// Licensed under GPLv2 or any later version
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// Refer to the license.txt file included.
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#include <atomic>
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#include <chrono>
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#include "core/settings.h"
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#include "video_core/renderer_vulkan/vk_device.h"
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#include "video_core/renderer_vulkan/vk_master_semaphore.h"
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#include "video_core/renderer_vulkan/wrapper.h"
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namespace Vulkan {
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using namespace std::chrono_literals;
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MasterSemaphore::MasterSemaphore(const VKDevice& device) {
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static constexpr VkSemaphoreTypeCreateInfoKHR semaphore_type_ci{
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.sType = VK_STRUCTURE_TYPE_SEMAPHORE_TYPE_CREATE_INFO_KHR,
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.pNext = nullptr,
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.semaphoreType = VK_SEMAPHORE_TYPE_TIMELINE_KHR,
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.initialValue = 0,
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};
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static constexpr VkSemaphoreCreateInfo semaphore_ci{
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.sType = VK_STRUCTURE_TYPE_SEMAPHORE_CREATE_INFO,
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.pNext = &semaphore_type_ci,
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.flags = 0,
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};
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semaphore = device.GetLogical().CreateSemaphore(semaphore_ci);
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if (!Settings::values.renderer_debug) {
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return;
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}
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// Validation layers have a bug where they fail to track resource usage when using timeline
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// semaphores and synchronizing with GetSemaphoreCounterValueKHR. To workaround this issue, have
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// a separate thread waiting for each timeline semaphore value.
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debug_thread = std::thread([this] {
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u64 counter = 0;
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while (!shutdown) {
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if (semaphore.Wait(counter, 10'000'000)) {
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++counter;
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}
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}
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});
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}
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MasterSemaphore::~MasterSemaphore() {
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shutdown = true;
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// This thread might not be started
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if (debug_thread.joinable()) {
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debug_thread.join();
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}
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}
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} // namespace Vulkan
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