Implement Vulkan Descriptor Set Allocator

A fixed descriptor set allocator which manages the size of the pool with automatic reallocations when any allocations run out of descriptors.
This commit is contained in:
PixelyIon 2021-12-22 17:54:00 +05:30
parent 9af9f1d41a
commit 492dd47218
5 changed files with 147 additions and 0 deletions

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@ -159,6 +159,7 @@ add_library(skyline SHARED
${source_DIR}/skyline/gpu/texture_manager.cpp
${source_DIR}/skyline/gpu/buffer_manager.cpp
${source_DIR}/skyline/gpu/command_scheduler.cpp
${source_DIR}/skyline/gpu/descriptor_allocator.cpp
${source_DIR}/skyline/gpu/texture/texture.cpp
${source_DIR}/skyline/gpu/buffer.cpp
${source_DIR}/skyline/gpu/presentation_engine.cpp

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@ -214,5 +214,6 @@ namespace skyline::gpu {
presentation(state, *this),
texture(*this),
buffer(*this),
descriptor(*this),
shader(state, *this) {}
}

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@ -9,6 +9,7 @@
#include "gpu/presentation_engine.h"
#include "gpu/texture_manager.h"
#include "gpu/buffer_manager.h"
#include "gpu/descriptor_allocator.h"
#include "gpu/shader_manager.h"
namespace skyline::gpu {
@ -48,6 +49,7 @@ namespace skyline::gpu {
TextureManager texture;
BufferManager buffer;
DescriptorAllocator descriptor;
ShaderManager shader;
GPU(const DeviceState &state);

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@ -0,0 +1,80 @@
// SPDX-License-Identifier: MPL-2.0
// Copyright © 2021 Skyline Team and Contributors (https://github.com/skyline-emu/)
#include <gpu.h>
#include <soc/gm20b/engines/maxwell/types.h>
#include "descriptor_allocator.h"
namespace skyline::gpu {
DescriptorAllocator::DescriptorPool::DescriptorPool(const vk::raii::Device &device, const vk::DescriptorPoolCreateInfo &createInfo) : vk::raii::DescriptorPool(device, createInfo), setCount(createInfo.maxSets) {}
void DescriptorAllocator::AllocateDescriptorPool() {
namespace maxwell3d = soc::gm20b::engine::maxwell3d::type; // We use Maxwell3D as reference for base descriptor counts
using DescriptorSizes = std::array<vk::DescriptorPoolSize, 1>;
constexpr DescriptorSizes BaseDescriptorSizes{
vk::DescriptorPoolSize{
.descriptorCount = maxwell3d::PipelineStageConstantBufferCount,
.type = vk::DescriptorType::eUniformBuffer,
},
};
DescriptorSizes descriptorSizes{BaseDescriptorSizes};
for (auto &descriptorSize : descriptorSizes)
descriptorSize.descriptorCount *= descriptorMultiplier;
pool = std::make_shared<DescriptorPool>(gpu.vkDevice, vk::DescriptorPoolCreateInfo{
.flags = vk::DescriptorPoolCreateFlagBits::eFreeDescriptorSet,
.maxSets = descriptorSetCount,
.pPoolSizes = descriptorSizes.data(),
.poolSizeCount = descriptorSizes.size(),
});
}
DescriptorAllocator::ActiveDescriptorSet::ActiveDescriptorSet(std::shared_ptr<DescriptorPool> pPool, vk::DescriptorSet set) : pool(std::move(pPool)), DescriptorSet(set) {
pool->setCount--;
}
DescriptorAllocator::ActiveDescriptorSet::~ActiveDescriptorSet() {
std::scoped_lock lock(*pool);
pool->getDevice().freeDescriptorSets(**pool, 1, this, *pool->getDispatcher());
pool->setCount++;
}
DescriptorAllocator::DescriptorAllocator(GPU &gpu) : gpu(gpu) {
AllocateDescriptorPool();
}
DescriptorAllocator::ActiveDescriptorSet DescriptorAllocator::AllocateSet(vk::DescriptorSetLayout layout) {
std::scoped_lock allocatorLock(mutex);
while (true) {
std::scoped_lock poolLock(*pool);
vk::DescriptorSetAllocateInfo allocateInfo{
.descriptorPool = **pool,
.pSetLayouts = &layout,
.descriptorSetCount = 1,
};
vk::DescriptorSet set{};
auto result{(*gpu.vkDevice).allocateDescriptorSets(&allocateInfo, &set, *gpu.vkDevice.getDispatcher())};
if (result == vk::Result::eSuccess) {
return ActiveDescriptorSet(pool, set);
} else if (result == vk::Result::eErrorOutOfPoolMemory) {
if (pool->setCount == 0)
// The amount of maximum descriptor sets is insufficient
descriptorSetCount += BaseDescriptorSetCount;
else
// The amount of maximum descriptors is insufficient
descriptorMultiplier++;
AllocateDescriptorPool();
continue; // Attempt to allocate again with the new pool
} else if (result == vk::Result::eErrorFragmentedPool) {
AllocateDescriptorPool(); // If the pool is fragmented, we reallocate without increasing the size
continue;
} else {
vk::throwResultException(result, __builtin_FUNCTION());
}
}
}
}

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@ -0,0 +1,63 @@
// SPDX-License-Identifier: MPL-2.0
// Copyright © 2021 Skyline Team and Contributors (https://github.com/skyline-emu/)
#pragma once
#include "fence_cycle.h"
namespace skyline::gpu {
/**
* @brief A dynamic descriptor set allocator with internal resizing of the descriptor pool to size up to allocation demand
*/
class DescriptorAllocator {
private:
GPU &gpu;
std::mutex mutex; //!< Synchronizes the creation and replacement of the pool object
static constexpr u32 BaseDescriptorSetCount{64}; //!< An arbitrary amount of descriptor sets that we allocate in multiples of
u32 descriptorSetCount{BaseDescriptorSetCount}; //!< The maximum amount of descriptor sets in the pool
u32 descriptorMultiplier{1}; //!< A multiplier for the maximum amount of descriptors in the pool
/**
* @brief A lockable VkDescriptorPool for maintaining external synchronization requirements
*/
struct DescriptorPool : public std::mutex, public vk::raii::DescriptorPool {
u64 setCount{}; //!< The amount of sets free to allocate from this pool
DescriptorPool(vk::raii::Device const &device, vk::DescriptorPoolCreateInfo const &createInfo);
};
std::shared_ptr<DescriptorPool> pool; //!< The current pool used by any allocations in the class, replaced when an error is ran into
/**
* @brief (Re-)Allocates the descriptor pool with the current multiplier applied to the base counts
* @note `DescriptorAllocator::mutex` **must** be locked prior to calling this
*/
void AllocateDescriptorPool();
public:
/**
* @brief A RAII-bound descriptor set that automatically frees of resources into the pool on destruction while respecting external synchronization requirements
*/
struct ActiveDescriptorSet : public vk::DescriptorSet {
private:
friend DescriptorAllocator;
std::shared_ptr<DescriptorPool> pool;
/**
* @note The supplied pool **must** be locked prior to calling this
*/
ActiveDescriptorSet(std::shared_ptr<DescriptorPool> pool, vk::DescriptorSet set);
public:
~ActiveDescriptorSet();
};
DescriptorAllocator(GPU &gpu);
/**
* @note It is UB to allocate a set with a descriptor type that isn't in the pool
*/
ActiveDescriptorSet AllocateSet(vk::DescriptorSetLayout layout);
};
}