VK_MEMORY_HEAP_MULTI_INSTANCE_BIT specifies that in a logical device representing more than one physical device, there is a per-physical device instance of the heap memory. By default, an allocation from such a heap will be replicated to each physical device’s instance of the heap.

vkEnumeratePhysicalDeviceGroups - Enumerates groups of physical devices that can be used to create a single logical device

Parameters

• instance is a handle to a Vulkan instance previously created with vkCreateInstance.

• pPhysicalDeviceGroupCount is a pointer to an integer related to the number of device groups available or queried, as described below.
• pPhysicalDeviceGroupProperties is either NULL or a pointer to an array of VkPhysicalDeviceGroupProperties structures.

Description

If pPhysicalDeviceGroupProperties is NULL, then the number of device groups available is returned in pPhysicalDeviceGroupCount. Otherwise, pPhysicalDeviceGroupCount must point to a variable set by the user to the number of elements in the pPhysicalDeviceGroupProperties array, and on return the variable is overwritten with the number of structures actually written to pPhysicalDeviceGroupProperties. If pPhysicalDeviceGroupCount is less than the number of device groups available, at most pPhysicalDeviceGroupCount structures will be written. If pPhysicalDeviceGroupCount is smaller than the number of device groups available, VK_INCOMPLETE will be returned instead of VK_SUCCESS, to indicate that not all the available device groups were returned.

Every physical device must be in exactly one device group.

Valid Usage (Implicit)

• instance must be a valid VkInstance handle

• pPhysicalDeviceGroupCount must be a valid pointer to a uint32_t value
• If the value referenced by pPhysicalDeviceGroupCount is not 0, and pPhysicalDeviceGroupProperties is not NULL, pPhysicalDeviceGroupProperties must be a valid pointer to an array of pPhysicalDeviceGroupCount VkPhysicalDeviceGroupProperties structures

Return Codes

[Success] - VK_SUCCESS

• VK_INCOMPLETE

[Failure] - VK_ERROR_OUT_OF_HOST_MEMORY

• VK_ERROR_OUT_OF_DEVICE_MEMORY

• VK_ERROR_INITIALIZATION_FAILED

See Also

VkInstance, VkPhysicalDeviceGroupProperties

VkPhysicalDeviceGroupProperties - Structure specifying physical device group properties

See Also

VkBool32, VkPhysicalDevice, VkStructureType, vkEnumeratePhysicalDeviceGroups, vkEnumeratePhysicalDeviceGroupsKHR

VkDeviceGroupDeviceCreateInfo - Create a logical device from multiple physical devices

Description

The elements of the pPhysicalDevices array are an ordered list of the physical devices that the logical device represents. These must be a subset of a single device group, and need not be in the same order as they were enumerated. The order of the physical devices in the pPhysicalDevices array determines the device index of each physical device, with element i being assigned a device index of i. Certain commands and structures refer to one or more physical devices by using device indices or device masks formed using device indices.

A logical device created without using VkDeviceGroupDeviceCreateInfo, or with physicalDeviceCount equal to zero, is equivalent to a physicalDeviceCount of one and pPhysicalDevices pointing to the physicalDevice parameter to vkCreateDevice. In particular, the device index of that physical device is zero.

Valid Usage

• Each element of pPhysicalDevices must be unique

• All elements of pPhysicalDevices must be in the same device group as enumerated by vkEnumeratePhysicalDeviceGroups
• If physicalDeviceCount is not 0, the physicalDevice parameter of vkCreateDevice must be an element of pPhysicalDevices.

Valid Usage (Implicit)

• sType must be VK_STRUCTURE_TYPE_DEVICE_GROUP_DEVICE_CREATE_INFO

• If physicalDeviceCount is not 0, pPhysicalDevices must be a valid pointer to an array of physicalDeviceCount valid VkPhysicalDevice handles

See Also

VkPhysicalDevice, VkStructureType