duckstation

vulkan_stream_buffer.cpp (10460B)

---

 // SPDX-FileCopyrightText: 2019-2023 Connor McLaughlin <stenzek@gmail.com>
 // SPDX-License-Identifier: (GPL-3.0 OR CC-BY-NC-ND-4.0)
 
 #include "vulkan_stream_buffer.h"
 #include "vulkan_builders.h"
 #include "vulkan_device.h"
 
 #include "common/align.h"
 #include "common/assert.h"
 #include "common/bitutils.h"
 #include "common/log.h"
 Log_SetChannel(VulkanDevice);
 
 VulkanStreamBuffer::VulkanStreamBuffer() = default;
 
 VulkanStreamBuffer::VulkanStreamBuffer(VulkanStreamBuffer&& move)
   : m_size(move.m_size), m_current_offset(move.m_current_offset), m_current_space(move.m_current_space),
     m_current_gpu_position(move.m_current_gpu_position), m_allocation(move.m_allocation), m_buffer(move.m_buffer),
     m_host_pointer(move.m_host_pointer), m_tracked_fences(std::move(move.m_tracked_fences))
 {
   move.m_size = 0;
   move.m_current_offset = 0;
   move.m_current_space = 0;
   move.m_current_gpu_position = 0;
   move.m_allocation = VK_NULL_HANDLE;
   move.m_buffer = VK_NULL_HANDLE;
   move.m_host_pointer = nullptr;
 }
 
 VulkanStreamBuffer::~VulkanStreamBuffer()
 {
   if (IsValid())
     Destroy(true);
 }
 
 VulkanStreamBuffer& VulkanStreamBuffer::operator=(VulkanStreamBuffer&& move)
 {
   if (IsValid())
     Destroy(true);
 
   std::swap(m_size, move.m_size);
   std::swap(m_current_offset, move.m_current_offset);
   std::swap(m_current_space, move.m_current_space);
   std::swap(m_current_gpu_position, move.m_current_gpu_position);
   std::swap(m_buffer, move.m_buffer);
   std::swap(m_host_pointer, move.m_host_pointer);
   std::swap(m_tracked_fences, move.m_tracked_fences);
 
   return *this;
 }
 
 bool VulkanStreamBuffer::Create(VkBufferUsageFlags usage, u32 size)
 {
   const VkBufferCreateInfo bci = {VK_STRUCTURE_TYPE_BUFFER_CREATE_INFO,
                                   nullptr,
                                   0,
                                   static_cast<VkDeviceSize>(size),
                                   usage,
                                   VK_SHARING_MODE_EXCLUSIVE,
                                   0,
                                   nullptr};
 
   VmaAllocationCreateInfo aci = {};
   aci.flags = VMA_ALLOCATION_CREATE_MAPPED_BIT;
   aci.usage = VMA_MEMORY_USAGE_CPU_TO_GPU;
   aci.preferredFlags = VK_MEMORY_PROPERTY_HOST_COHERENT_BIT;
 
   VmaAllocationInfo ai = {};
   VkBuffer new_buffer = VK_NULL_HANDLE;
   VmaAllocation new_allocation = VK_NULL_HANDLE;
   VkResult res =
     vmaCreateBuffer(VulkanDevice::GetInstance().GetAllocator(), &bci, &aci, &new_buffer, &new_allocation, &ai);
   if (res != VK_SUCCESS)
   {
     LOG_VULKAN_ERROR(res, "vkCreateBuffer failed: ");
     return false;
   }
 
   if (IsValid())
     Destroy(true);
 
   // Replace with the new buffer
   m_size = size;
   m_current_offset = 0;
   m_current_gpu_position = 0;
   m_tracked_fences.clear();
   m_allocation = new_allocation;
   m_buffer = new_buffer;
   m_host_pointer = static_cast<u8*>(ai.pMappedData);
   return true;
 }
 
 void VulkanStreamBuffer::Destroy(bool defer)
 {
   if (m_buffer != VK_NULL_HANDLE)
   {
     if (defer)
       VulkanDevice::GetInstance().DeferBufferDestruction(m_buffer, m_allocation);
     else
       vmaDestroyBuffer(VulkanDevice::GetInstance().GetAllocator(), m_buffer, m_allocation);
   }
 
   m_size = 0;
   m_current_offset = 0;
   m_current_gpu_position = 0;
   m_tracked_fences.clear();
   m_buffer = VK_NULL_HANDLE;
   m_allocation = VK_NULL_HANDLE;
   m_host_pointer = nullptr;
 }
 
 bool VulkanStreamBuffer::ReserveMemory(u32 num_bytes, u32 alignment)
 {
   const u32 required_bytes = num_bytes + alignment;
 
   // Check for sane allocations
   if (required_bytes > m_size) [[unlikely]]
   {
     ERROR_LOG("Attempting to allocate {} bytes from a {} byte stream buffer", num_bytes, m_size);
     Panic("Stream buffer overflow");
   }
 
   UpdateGPUPosition();
 
   // Is the GPU behind or up to date with our current offset?
   if (m_current_offset >= m_current_gpu_position)
   {
     const u32 remaining_bytes = m_size - m_current_offset;
     if (required_bytes <= remaining_bytes)
     {
       // Place at the current position, after the GPU position.
       m_current_offset = Common::AlignUp(m_current_offset, alignment);
       m_current_space = m_size - m_current_offset;
       return true;
     }
 
     // Check for space at the start of the buffer
     // We use < here because we don't want to have the case of m_current_offset ==
     // m_current_gpu_position. That would mean the code above would assume the
     // GPU has caught up to us, which it hasn't.
     if (required_bytes < m_current_gpu_position)
     {
       // Reset offset to zero, since we're allocating behind the gpu now
       m_current_offset = 0;
       m_current_space = m_current_gpu_position - 1;
       return true;
     }
   }
 
   // Is the GPU ahead of our current offset?
   if (m_current_offset < m_current_gpu_position)
   {
     // We have from m_current_offset..m_current_gpu_position space to use.
     const u32 remaining_bytes = m_current_gpu_position - m_current_offset;
     if (required_bytes < remaining_bytes)
     {
       // Place at the current position, since this is still behind the GPU.
       m_current_offset = Common::AlignUp(m_current_offset, alignment);
       m_current_space = m_current_gpu_position - m_current_offset - 1;
       return true;
     }
   }
 
   // Can we find a fence to wait on that will give us enough memory?
   if (WaitForClearSpace(required_bytes))
   {
     const u32 align_diff = Common::AlignUp(m_current_offset, alignment) - m_current_offset;
     m_current_offset += align_diff;
     m_current_space -= align_diff;
     return true;
   }
 
   // We tried everything we could, and still couldn't get anything. This means that too much space
   // in the buffer is being used by the command buffer currently being recorded. Therefore, the
   // only option is to execute it, and wait until it's done.
   return false;
 }
 
 void VulkanStreamBuffer::CommitMemory(u32 final_num_bytes)
 {
   DebugAssert((m_current_offset + final_num_bytes) <= m_size);
   DebugAssert(final_num_bytes <= m_current_space);
 
   // For non-coherent mappings, flush the memory range
   vmaFlushAllocation(VulkanDevice::GetInstance().GetAllocator(), m_allocation, m_current_offset, final_num_bytes);
 
   m_current_offset += final_num_bytes;
   m_current_space -= final_num_bytes;
   UpdateCurrentFencePosition();
 }
 
 void VulkanStreamBuffer::UpdateCurrentFencePosition()
 {
   // Has the offset changed since the last fence?
   const u64 counter = VulkanDevice::GetInstance().GetCurrentFenceCounter();
   if (!m_tracked_fences.empty() && m_tracked_fences.back().first == counter)
   {
     // Still haven't executed a command buffer, so just update the offset.
     m_tracked_fences.back().second = m_current_offset;
     return;
   }
 
   // New buffer, so update the GPU position while we're at it.
   m_tracked_fences.emplace_back(counter, m_current_offset);
 }
 
 void VulkanStreamBuffer::UpdateGPUPosition()
 {
   auto start = m_tracked_fences.begin();
   auto end = start;
 
   const u64 completed_counter = VulkanDevice::GetInstance().GetCompletedFenceCounter();
   while (end != m_tracked_fences.end() && completed_counter >= end->first)
   {
     m_current_gpu_position = end->second;
     ++end;
   }
 
   if (start != end)
   {
     m_tracked_fences.erase(start, end);
     if (m_current_offset == m_current_gpu_position)
     {
       // GPU is all caught up now.
       m_current_offset = 0;
       m_current_gpu_position = 0;
       m_current_space = m_size;
     }
   }
 }
 
 bool VulkanStreamBuffer::WaitForClearSpace(u32 num_bytes)
 {
   u32 new_offset = 0;
   u32 new_space = 0;
   u32 new_gpu_position = 0;
 
   auto iter = m_tracked_fences.begin();
   for (; iter != m_tracked_fences.end(); ++iter)
   {
     // Would this fence bring us in line with the GPU?
     // This is the "last resort" case, where a command buffer execution has been forced
     // after no additional data has been written to it, so we can assume that after the
     // fence has been signaled the entire buffer is now consumed.
     u32 gpu_position = iter->second;
     if (m_current_offset == gpu_position)
     {
       new_offset = 0;
       new_space = m_size;
       new_gpu_position = 0;
       break;
     }
 
     // Assuming that we wait for this fence, are we allocating in front of the GPU?
     if (m_current_offset > gpu_position)
     {
       // This would suggest the GPU has now followed us and wrapped around, so we have from
       // m_current_position..m_size free, as well as and 0..gpu_position.
       const u32 remaining_space_after_offset = m_size - m_current_offset;
       if (remaining_space_after_offset >= num_bytes)
       {
         // Switch to allocating in front of the GPU, using the remainder of the buffer.
         new_offset = m_current_offset;
         new_space = m_size - m_current_offset;
         new_gpu_position = gpu_position;
         break;
       }
 
       // We can wrap around to the start, behind the GPU, if there is enough space.
       // We use > here because otherwise we'd end up lining up with the GPU, and then the
       // allocator would assume that the GPU has consumed what we just wrote.
       if (gpu_position > num_bytes)
       {
         new_offset = 0;
         new_space = gpu_position - 1;
         new_gpu_position = gpu_position;
         break;
       }
     }
     else
     {
       // We're currently allocating behind the GPU. This would give us between the current
       // offset and the GPU position worth of space to work with. Again, > because we can't
       // align the GPU position with the buffer offset.
       u32 available_space_inbetween = gpu_position - m_current_offset;
       if (available_space_inbetween > num_bytes)
       {
         // Leave the offset as-is, but update the GPU position.
         new_offset = m_current_offset;
         new_space = available_space_inbetween - 1;
         new_gpu_position = gpu_position;
         break;
       }
     }
   }
 
   // Did any fences satisfy this condition?
   // Has the command buffer been executed yet? If not, the caller should execute it.
   if (iter == m_tracked_fences.end() || iter->first == VulkanDevice::GetInstance().GetCurrentFenceCounter())
     return false;
 
   // Wait until this fence is signaled. This will fire the callback, updating the GPU position.
   VulkanDevice::GetInstance().WaitForFenceCounter(iter->first);
   m_tracked_fences.erase(m_tracked_fences.begin(), m_current_offset == iter->second ? m_tracked_fences.end() : ++iter);
   m_current_offset = new_offset;
   m_current_space = new_space;
   m_current_gpu_position = new_gpu_position;
   return true;
 }