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Pick dedicated GPU with highest VRAM (Vulkan) #13755

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Merged
merged 3 commits into from
Aug 18, 2025
Merged

Pick dedicated GPU with highest VRAM (Vulkan) #13755

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ac74f9c
Pick dedicated GPU with highest VRAM
suleyth Aug 16, 2025
4df1c2c
Make deviceRank an Uint64 to avoid potential overflow issues in case …
suleyth Aug 17, 2025
ebe2262
Only add VRAM to deviceRank if asking for a high performance device, …
suleyth Aug 17, 2025
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23 changes: 21 additions & 2 deletions src/gpu/vulkan/SDL_gpu_vulkan.c
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Original file line number Diff line number Diff line change
Expand Up @@ -11252,13 +11252,14 @@ static Uint8 VULKAN_INTERNAL_IsDeviceSuitable(
VkPhysicalDevice physicalDevice,
VulkanExtensions *physicalDeviceExtensions,
Uint32 *queueFamilyIndex,
Uint8 *deviceRank)
Uint16 *deviceRank)
{
Uint32 queueFamilyCount, queueFamilyRank, queueFamilyBest;
VkQueueFamilyProperties *queueProps;
bool supportsPresent;
VkPhysicalDeviceProperties deviceProperties;
VkPhysicalDeviceFeatures deviceFeatures;
VkPhysicalDeviceMemoryProperties deviceMemory;
Uint32 i;

const Uint8 *devicePriority = renderer->preferLowPower ? DEVICE_PRIORITY_LOWPOWER : DEVICE_PRIORITY_HIGHPERFORMANCE;
Expand All @@ -11285,6 +11286,24 @@ static Uint8 VULKAN_INTERNAL_IsDeviceSuitable(
return 0;
}

/* If we prefer high performance, sum up all device local memory (rounded to megabytes)
* to deviceRank. In the niche case of someone having multiple dedicated GPUs in the same
* system, this theoretically picks the most powerful one (or at least the one with the
* most memory!)
*/

renderer->vkGetPhysicalDeviceMemoryProperties(physicalDevice, &deviceMemory);
Uint64 videoMemory = 0;
for (i = 0; i < deviceMemory.memoryHeapCount; i++) {
VkMemoryHeap heap = deviceMemory.memoryHeaps[i];
if (heap.flags & VK_MEMORY_HEAP_DEVICE_LOCAL_BIT) {
videoMemory += heap.size;
}
}
// Round it to megabytes (as per the vulkan spec videoMemory is in bytes)
Uint64 videoMemoryRounded = videoMemory / 1024 / 1024;
*deviceRank += videoMemoryRounded;

renderer->vkGetPhysicalDeviceFeatures(
physicalDevice,
&deviceFeatures);
Expand Down Expand Up @@ -11392,7 +11411,7 @@ static Uint8 VULKAN_INTERNAL_DeterminePhysicalDevice(VulkanRenderer *renderer)
Uint32 i, physicalDeviceCount;
Sint32 suitableIndex;
Uint32 queueFamilyIndex, suitableQueueFamilyIndex;
Uint8 deviceRank, highestRank;
Uint16 deviceRank, highestRank;

vulkanResult = renderer->vkEnumeratePhysicalDevices(
renderer->instance,
Expand Down
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