[dxvk] Refactor descriptor set allocation

With this new approach, descriptor pools are decoupled from the
command list they are used with. Instead, the DXVK context takes
ownership of a single descriptor pool until it runs out of memory.

This reduces the amount of memory wasted for under-utilized pools
and should this reduce an application's memory footprint.

src/dxvk/dxvk_cmdlist.cpp

@@ -8,7 +8,7 @@ namespace dxvk {
           uint32_t          queueFamily)
   : m_vkd           (device->vkd()),
     m_cmdBuffersUsed(0),
-    m_descAlloc     (device->vkd()),
+    m_descriptorPoolTracker(device),
     m_stagingAlloc  (device) {
     VkFenceCreateInfo fenceInfo;
     fenceInfo.sType = VK_STRUCTURE_TYPE_FENCE_CREATE_INFO;
@@ -127,7 +127,7 @@ namespace dxvk {
     m_eventTracker.reset();
     m_queryTracker.reset();
     m_stagingAlloc.reset();
-    m_descAlloc.reset();
+    m_descriptorPoolTracker.reset();
     m_resources.reset();
   }
   

src/dxvk/dxvk_cmdlist.h

@@ -157,6 +157,14 @@ namespace dxvk {
       m_eventTracker.trackEvent(event);
     }
 
+    /**
+     * \brief Tracks a descriptor pool
+     * \param [in] pool The descriptor pool
+     */
+    void trackDescriptorPool(Rc<DxvkDescriptorPool> pool) {
+      m_descriptorPoolTracker.trackDescriptorPool(pool);
+    }
+    
     /**
      * \brief Signals tracked events
      * 
@@ -188,12 +196,6 @@ namespace dxvk {
      */
     void reset();
     
-    VkDescriptorSet allocateDescriptorSet(
-            VkDescriptorSetLayout   descriptorLayout) {
-      return m_descAlloc.alloc(descriptorLayout);
-    }
-    
-    
     void updateDescriptorSets(
             uint32_t                      descriptorWriteCount,
       const VkWriteDescriptorSet*         pDescriptorWrites) {
@@ -656,7 +658,7 @@ namespace dxvk {
     
     DxvkCmdBufferFlags  m_cmdBuffersUsed;
     DxvkLifetimeTracker m_resources;
-    DxvkDescriptorAlloc m_descAlloc;
+    DxvkDescriptorPoolTracker m_descriptorPoolTracker;
     DxvkStagingAlloc    m_stagingAlloc;
     DxvkQueryTracker    m_queryTracker;
     DxvkEventTracker    m_eventTracker;

src/dxvk/dxvk_context.cpp

@@ -296,8 +296,7 @@ namespace dxvk {
     // Create a descriptor set pointing to the view
     VkBufferView viewObject = bufferView->handle();
     
-    VkDescriptorSet descriptorSet =
+    VkDescriptorSet descriptorSet = allocateDescriptorSet(pipeInfo.dsetLayout);
-      m_cmd->allocateDescriptorSet(pipeInfo.dsetLayout);
     
     VkWriteDescriptorSet descriptorWrite;
     descriptorWrite.sType            = VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET;
@@ -963,7 +962,7 @@ namespace dxvk {
     descriptors.srcDepth   = dView->getDescriptor(VK_IMAGE_VIEW_TYPE_2D_ARRAY, layout).image;
     descriptors.srcStencil = sView->getDescriptor(VK_IMAGE_VIEW_TYPE_2D_ARRAY, layout).image;
 
-    VkDescriptorSet dset = m_cmd->allocateDescriptorSet(pipeInfo.dsetLayout);
+    VkDescriptorSet dset = allocateDescriptorSet(pipeInfo.dsetLayout);
     m_cmd->updateDescriptorSetWithTemplate(dset, pipeInfo.dsetTemplate, &descriptors);
 
     // Since this is a meta operation, the image may be
@@ -1290,7 +1289,7 @@ namespace dxvk {
       
       // Create descriptor set with the current source view
       descriptorImage.imageView = pass.srcView;
-      descriptorWrite.dstSet = m_cmd->allocateDescriptorSet(pipeInfo.dsetLayout);
+      descriptorWrite.dstSet = allocateDescriptorSet(pipeInfo.dsetLayout);
       m_cmd->updateDescriptorSets(1, &descriptorWrite);
       
       // Set up viewport and scissor rect
@@ -1802,8 +1801,7 @@ namespace dxvk {
       imageView->type(), imageFormatInfo(imageView->info().format)->flags);
     
     // Create a descriptor set pointing to the view
-    VkDescriptorSet descriptorSet =
+    VkDescriptorSet descriptorSet = allocateDescriptorSet(pipeInfo.dsetLayout);
-      m_cmd->allocateDescriptorSet(pipeInfo.dsetLayout);
     
     VkDescriptorImageInfo viewInfo;
     viewInfo.sampler      = VK_NULL_HANDLE;
@@ -2077,7 +2075,7 @@ namespace dxvk {
     descriptorWrite.pBufferInfo      = nullptr;
     descriptorWrite.pTexelBufferView = nullptr;
     
-    descriptorWrite.dstSet = m_cmd->allocateDescriptorSet(pipeInfo.dsetLayout);
+    descriptorWrite.dstSet = allocateDescriptorSet(pipeInfo.dsetLayout);
     m_cmd->updateDescriptorSets(1, &descriptorWrite);
     
     VkViewport viewport;
@@ -2272,7 +2270,7 @@ namespace dxvk {
     descriptorWrite.pBufferInfo      = nullptr;
     descriptorWrite.pTexelBufferView = nullptr;
     
-    descriptorWrite.dstSet = m_cmd->allocateDescriptorSet(pipeInfo.dsetLayout);
+    descriptorWrite.dstSet = allocateDescriptorSet(pipeInfo.dsetLayout);
     m_cmd->updateDescriptorSets(1, &descriptorWrite);
 
     // Set up viewport and scissor rect
@@ -2814,7 +2812,7 @@ namespace dxvk {
     VkDescriptorSet descriptorSet = VK_NULL_HANDLE;
 
     if (layout->bindingCount() != 0) {
-      descriptorSet = m_cmd->allocateDescriptorSet(
+      descriptorSet = allocateDescriptorSet(
         layout->descriptorSetLayout());
       
       m_cmd->updateDescriptorSetWithTemplate(
@@ -3259,6 +3257,24 @@ namespace dxvk {
   }
 
 
+  VkDescriptorSet DxvkContext::allocateDescriptorSet(
+          VkDescriptorSetLayout     layout) {
+    if (m_descPool == nullptr)
+      m_descPool = m_device->createDescriptorPool();
+    
+    VkDescriptorSet set = m_descPool->alloc(layout);
+
+    if (set == VK_NULL_HANDLE) {
+      m_cmd->trackDescriptorPool(std::move(m_descPool));
+
+      m_descPool = m_device->createDescriptorPool();
+      set = m_descPool->alloc(layout);
+    }
+
+    return set;
+  }
+
+  
   void DxvkContext::trackDrawBuffer() {
     if (m_flags.test(DxvkContextFlag::DirtyDrawBuffer)) {
       m_flags.clr(DxvkContextFlag::DirtyDrawBuffer);

src/dxvk/dxvk_context.h

@@ -769,6 +769,8 @@ namespace dxvk {
     const Rc<DxvkMetaResolveObjects>  m_metaResolve;
     
     Rc<DxvkCommandList>     m_cmd;
+    Rc<DxvkDescriptorPool>  m_descPool;
+
     DxvkContextFlags    m_flags;
     DxvkContextState    m_state;
 
@@ -903,6 +905,9 @@ namespace dxvk {
             VkPipelineStageFlags      dstStages,
             VkAccessFlags             dstAccess);
     
+    VkDescriptorSet allocateDescriptorSet(
+            VkDescriptorSetLayout     layout);
+
     void trackDrawBuffer();
     
   };

src/dxvk/dxvk_descriptor.cpp

@@ -1,50 +1,10 @@
 #include "dxvk_descriptor.h"
+#include "dxvk_device.h"
 
 namespace dxvk {
   
-  DxvkDescriptorAlloc::DxvkDescriptorAlloc(
+  DxvkDescriptorPool::DxvkDescriptorPool(const Rc<vk::DeviceFn>& vkd)
-    const Rc<vk::DeviceFn>& vkd)
   : m_vkd(vkd) {
-    // Allocate one pool right away so that there
-    // is always at least one pool available when
-    // allocating a descriptor set
-    m_pools.push_back(createDescriptorPool());
-  }
-  
-  
-  DxvkDescriptorAlloc::~DxvkDescriptorAlloc() {
-    for (auto p : m_pools) {
-      m_vkd->vkDestroyDescriptorPool(
-        m_vkd->device(), p, nullptr);
-    }
-  }
-  
-  
-  VkDescriptorSet DxvkDescriptorAlloc::alloc(VkDescriptorSetLayout layout) {
-    VkDescriptorSet set = allocFrom(m_pools[m_poolId], layout);
-    
-    if (set == VK_NULL_HANDLE) {
-      if (++m_poolId >= m_pools.size())
-        m_pools.push_back(createDescriptorPool());
-      
-      set = allocFrom(m_pools[m_poolId], layout);
-    }
-    
-    return set;
-  }
-  
-  
-  void DxvkDescriptorAlloc::reset() {
-    for (auto p : m_pools) {
-      m_vkd->vkResetDescriptorPool(
-        m_vkd->device(), p, 0);
-    }
-    
-    m_poolId = 0;
-  }
-  
-  
-  VkDescriptorPool DxvkDescriptorAlloc::createDescriptorPool() {
     constexpr uint32_t MaxSets = 2048;
 
     std::array<VkDescriptorPoolSize, 10> pools = {{
@@ -67,21 +27,22 @@ namespace dxvk {
     info.poolSizeCount = pools.size();
     info.pPoolSizes    = pools.data();
     
-    VkDescriptorPool pool = VK_NULL_HANDLE;
+    if (m_vkd->vkCreateDescriptorPool(m_vkd->device(), &info, nullptr, &m_pool) != VK_SUCCESS)
-    if (m_vkd->vkCreateDescriptorPool(m_vkd->device(),
+      throw DxvkError("DxvkDescriptorPool: Failed to create descriptor pool");
-          &info, nullptr, &pool) != VK_SUCCESS)
-      throw DxvkError("DxvkDescriptorAlloc: Failed to create descriptor pool");
-    return pool;
   }
   
   
-  VkDescriptorSet DxvkDescriptorAlloc::allocFrom(
+  DxvkDescriptorPool::~DxvkDescriptorPool() {
-          VkDescriptorPool      pool,
+    m_vkd->vkDestroyDescriptorPool(
-          VkDescriptorSetLayout layout) const {
+      m_vkd->device(), m_pool, nullptr);
+  }
+  
+  
+  VkDescriptorSet DxvkDescriptorPool::alloc(VkDescriptorSetLayout layout) {
     VkDescriptorSetAllocateInfo info;
     info.sType              = VK_STRUCTURE_TYPE_DESCRIPTOR_SET_ALLOCATE_INFO;
     info.pNext              = nullptr;
-    info.descriptorPool     = pool;
+    info.descriptorPool     = m_pool;
     info.descriptorSetCount = 1;
     info.pSetLayouts        = &layout;
     
@@ -91,4 +52,38 @@ namespace dxvk {
     return set;
   }
   
+  
+  void DxvkDescriptorPool::reset() {
+    m_vkd->vkResetDescriptorPool(
+      m_vkd->device(), m_pool, 0);
+  }
+
+
+
+
+  DxvkDescriptorPoolTracker::DxvkDescriptorPoolTracker(DxvkDevice* device)
+  : m_device(device) {
+
+  }
+
+
+  DxvkDescriptorPoolTracker::~DxvkDescriptorPoolTracker() {
+
+  }
+
+
+  void DxvkDescriptorPoolTracker::trackDescriptorPool(Rc<DxvkDescriptorPool> pool) {
+    m_pools.push_back(std::move(pool));
+  }
+
+  
+  void DxvkDescriptorPoolTracker::reset() {
+    for (const auto& pool : m_pools) {
+      pool->reset();
+      m_device->recycleDescriptorPool(pool);
+    }
+
+    m_pools.clear();
+  }
+  
 }

src/dxvk/dxvk_descriptor.h

@@ -6,6 +6,8 @@
 
 namespace dxvk {
 
+  class DxvkDevice;
+  
   /**
    * \brief Descriptor info
    * 
@@ -20,21 +22,18 @@ namespace dxvk {
   
   
   /**
-   * \brief Descriptor set allocator
+   * \brief Descriptor pool
    * 
-   * Creates descriptor pools on demand and
+   * Wrapper around a Vulkan descriptor pool that
-   * allocates descriptor sets from those pools.
+   * descriptor sets can be allocated from.
    */
-  class DxvkDescriptorAlloc {
+  class DxvkDescriptorPool : public RcObject {
     
   public:
     
-    DxvkDescriptorAlloc(
+    DxvkDescriptorPool(
       const Rc<vk::DeviceFn>& vkd);
-    ~DxvkDescriptorAlloc();
+    ~DxvkDescriptorPool();
-    
-    DxvkDescriptorAlloc             (const DxvkDescriptorAlloc&) = delete;
-    DxvkDescriptorAlloc& operator = (const DxvkDescriptorAlloc&) = delete;
     
     /**
      * \brief Allocates a descriptor set
@@ -56,15 +55,45 @@ namespace dxvk {
   private:
     
     Rc<vk::DeviceFn> m_vkd;
+    VkDescriptorPool m_pool;
     
-    std::vector<VkDescriptorPool> m_pools;
+  };
-    size_t                        m_poolId = 0;
 
-    VkDescriptorPool createDescriptorPool();
 
-    VkDescriptorSet allocFrom(
+  /**
-      VkDescriptorPool      pool,
+   * \brief Descriptor pool tracker
-      VkDescriptorSetLayout layout) const;
+   * 
+   * Tracks descriptor pools that are either full
+   * or no longer needed by the DXVK context. The
+   * command list will reset and recycle all pools
+   * once it has completed execution on the GPU.
+   */
+  class DxvkDescriptorPoolTracker {
+
+  public:
+
+    DxvkDescriptorPoolTracker(DxvkDevice* device);
+    ~DxvkDescriptorPoolTracker();
+
+    /**
+     * \brief Adds a descriptor pool to track
+     * \param [in] pool The descriptor pool
+     */
+    void trackDescriptorPool(Rc<DxvkDescriptorPool> pool);
+    
+    /**
+     * \brief Resets event tracker
+     * 
+     * Resets all tracked descriptor pools
+     * and returns them to the device.
+     */
+    void reset();
+
+  private:
+
+    DxvkDevice* m_device;
+
+    std::vector<Rc<DxvkDescriptorPool>> m_pools;
 
   };
   

src/dxvk/dxvk_device.cpp

@@ -116,6 +116,16 @@ namespace dxvk {
   }
 
 
+  Rc<DxvkDescriptorPool> DxvkDevice::createDescriptorPool() {
+    Rc<DxvkDescriptorPool> pool = m_recycledDescriptorPools.retrieveObject();
+
+    if (pool == nullptr)
+      pool = new DxvkDescriptorPool(m_vkd);
+    
+    return pool;
+  }
+  
+  
   Rc<DxvkContext> DxvkDevice::createContext() {
     return new DxvkContext(this,
       m_pipelineManager,
@@ -296,4 +306,9 @@ namespace dxvk {
     m_recycledCommandLists.returnObject(cmdList);
   }
   
+
+  void DxvkDevice::recycleDescriptorPool(const Rc<DxvkDescriptorPool>& pool) {
+    m_recycledDescriptorPools.returnObject(pool);
+  }
+  
 }

src/dxvk/dxvk_device.h

@@ -58,6 +58,7 @@ namespace dxvk {
   class DxvkDevice : public RcObject {
     friend class DxvkContext;
     friend class DxvkSubmissionQueue;
+    friend class DxvkDescriptorPoolTracker;
     
     constexpr static VkDeviceSize DefaultStagingBufferSize = 4 * 1024 * 1024;
   public:
@@ -178,6 +179,16 @@ namespace dxvk {
      */
     Rc<DxvkCommandList> createCommandList();
     
+    /**
+     * \brief Creates a descriptor pool
+     * 
+     * Returns a previously recycled pool, or creates
+     * a new one if necessary. The context should take
+     * ownership of the returned pool.
+     * \returns Descriptor pool
+     */
+    Rc<DxvkDescriptorPool> createDescriptorPool();
+    
     /**
      * \brief Creates a context
      * 
@@ -414,6 +425,7 @@ namespace dxvk {
     DxvkDeviceQueue             m_presentQueue;
     
     DxvkRecycler<DxvkCommandList,    16> m_recycledCommandLists;
+    DxvkRecycler<DxvkDescriptorPool, 16> m_recycledDescriptorPools;
     DxvkRecycler<DxvkStagingBuffer,   4> m_recycledStagingBuffers;
     
     DxvkSubmissionQueue m_submissionQueue;
@@ -421,6 +433,9 @@ namespace dxvk {
     void recycleCommandList(
       const Rc<DxvkCommandList>& cmdList);
     
+    void recycleDescriptorPool(
+      const Rc<DxvkDescriptorPool>& pool);
+    
     /**
      * \brief Dummy buffer handle
      * \returns Use for unbound vertex buffers.