[d3d9] Add option to use device local memory for constant buffers

Useful for testing performance.

dxvk.conf

@@ -342,3 +342,15 @@
 # - True/False
 
 # d3d9.alphaTestWiggleRoom = False
+
+# Device Local Constant Buffers
+#
+# Enables using device local, host accessible memory for constant buffers in D3D9.
+# This tends to actually be slower for some reason on AMD,
+# and the exact same performance on NVIDIA.
+#
+# Supported values:
+# - True/False
+
+# d3d9.deviceLocalConstantBuffers = False
+

src/d3d9/d3d9_device.cpp

@@ -4627,6 +4627,9 @@ namespace dxvk {
     VkMemoryPropertyFlags memoryFlags = VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT
                                       | VK_MEMORY_PROPERTY_HOST_COHERENT_BIT;
 
+    if (m_d3d9Options.deviceLocalConstantBuffers)
+      memoryFlags |= VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT;
+
     Rc<DxvkBuffer> buffer = m_dxvkDevice->createBuffer(info, memoryFlags);
 
     const uint32_t slotId = computeResourceSlotId(

src/d3d9/d3d9_options.cpp

@@ -75,6 +75,8 @@ namespace dxvk {
 
     this->apitraceMode = config.getOption<bool>("d3d9.apitraceMode", false);
 
+    this->deviceLocalConstantBuffers = config.getOption<bool>("d3d9.deviceLocalConstantBuffers", false);
+
     // If we are not Nvidia, enable general hazards.
     this->generalHazards = adapter == nullptr || !adapter->matchesDriver(DxvkGpuVendor::Nvidia, VK_DRIVER_ID_NVIDIA_PROPRIETARY_KHR, 0, 0);
     applyTristate(this->generalHazards, config.getOption<Tristate>("d3d9.generalHazards", Tristate::Auto));

src/d3d9/d3d9_options.h

@@ -154,6 +154,9 @@ namespace dxvk {
 
     /// Apitrace mode: Maps all buffers in cached memory.
     bool apitraceMode;
+
+    /// Use device local memory for constant buffers.
+    bool deviceLocalConstantBuffers;
   };
 
 }