SwiftShader out of device memory error

[Dov Grobgeld]

Hello,

I'm using SwiftShader for Vulkan rendering for a project where I can't rely on having a functioning hardware implementation. Today I encountered an ERROR_OUT_OF_DEVICE_MEMORY when trying to allocate a large chunk of device memory through vkCreateBuffer(). Since SwiftShader is a software implementation, I assumed that the device memory is configurable. Is it? If so, how is it configured?

Here is my call that fails:

size_t sz=1323371088; // > 1GB size_t usage_flags = VK_BUFFER_USAGE_VERTEX_BUFFER_BIT | VK_BUFFER_USAGE_TRANSFER_DST_BIT; VkBufferCreateInfo bufferCreateInfo = vks::initializers::bufferCreateInfo(usageFlags, size); bufferCreateInfo.sharingMode = VK_SHARING_MODE_EXCLUSIVE; int ret = vkCreateBuffer(device, &bufferCreateInfo, nullptr, buffer);

(This example is using the VulkanInitializers.hpp macros by Sasha Willems.)

Thanks in advance!

[Alexis Hétu]

Hi, "device memory" is just regular RAM for SwiftShader, but the issue here is that your allocation exceeds the limit advertised by VkPhysicalDeviceMaintenance3Properties::maxMemoryAllocationSize, which, for SwiftShader, is 1Gb.

This limit can be queried by using a VkPhysicalDeviceMaintenance3Properties structure as a pNext pointer to the VkPhysicalDeviceProperties2 structure and call vkGetPhysicalDeviceProperties2().

Alexis

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[Dov Grobgeld]

Thanks for the explanation!

Is there any way of increasing maxMemoryAllocationSize without recompiling swiftShader?

[Nicolas Capens]

Hi Dov,

The maximum allocation size is currently hard-coded to be 1 GiB. This can be increased up to 2 GiB by adjusting the code and recompiling. It can currently be no more than 2 GiB due to signed 32-bit indices being used to address resources.

Increasing it to 4 GiB could be feasible by using unsigned indices, but it's not straightforward due to some of Vulkan's data offsets being signed.

Cheers,

Nicolas

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