Contact
- 
Carsten Rohde [GitHub]crohde 
Other Extension Metadata
- Last Modified Date
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2021-04-19 
- IP Status
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No known IP claims. 
- Contributors
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- 
Carsten Rohde, NVIDIA 
 
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Description
This extension adds support for allocating memory which can be used for remote direct memory access (RDMA) from other devices.
New Enum Constants
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VK_NV_EXTERNAL_MEMORY_RDMA_EXTENSION_NAME
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VK_NV_EXTERNAL_MEMORY_RDMA_SPEC_VERSION
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Extending VkExternalMemoryHandleTypeFlagBits: - 
VK_EXTERNAL_MEMORY_HANDLE_TYPE_RDMA_ADDRESS_BIT_NV
 
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Extending VkMemoryPropertyFlagBits: - 
VK_MEMORY_PROPERTY_RDMA_CAPABLE_BIT_NV
 
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Extending VkStructureType: - 
VK_STRUCTURE_TYPE_MEMORY_GET_REMOTE_ADDRESS_INFO_NV
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VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXTERNAL_MEMORY_RDMA_FEATURES_NV
 
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Examples
VkPhysicalDeviceMemoryBudgetPropertiesEXT memoryBudgetProperties = { VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MEMORY_BUDGET_PROPERTIES_EXT };
VkPhysicalDeviceMemoryProperties2 memoryProperties2 = { VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MEMORY_PROPERTIES_2, &memoryBudgetProperties };
vkGetPhysicalDeviceMemoryProperties2(physicalDevice, &memoryProperties2);
uint32_t heapIndex = (uint32_t)-1;
for (uint32_t memoryType = 0; memoryType < memoryProperties2.memoryProperties.memoryTypeCount; memoryType++) {
    if (memoryProperties2.memoryProperties.memoryTypes[memoryType].propertyFlags & VK_MEMORY_PROPERTY_RDMA_CAPABLE_BIT_NV) {
        heapIndex = memoryProperties2.memoryProperties.memoryTypes[memoryType].heapIndex;
        break;
    }
}
if ((heapIndex == (uint32_t)-1) ||
    (memoryBudgetProperties.heapBudget[heapIndex] < size)) {
    return;
}
VkPhysicalDeviceExternalBufferInfo externalBufferInfo = { VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXTERNAL_BUFFER_INFO };
externalBufferInfo.usage = VK_BUFFER_USAGE_TRANSFER_SRC_BIT | VK_BUFFER_USAGE_TRANSFER_DST_BIT;
externalBufferInfo.handleType = VK_EXTERNAL_MEMORY_HANDLE_TYPE_RDMA_ADDRESS_BIT_NV;
VkExternalBufferProperties externalBufferProperties = { VK_STRUCTURE_TYPE_EXTERNAL_BUFFER_PROPERTIES };
vkGetPhysicalDeviceExternalBufferProperties(physicalDevice, &externalBufferInfo, &externalBufferProperties);
if (!(externalBufferProperties.externalMemoryProperties.externalMemoryFeatures & VK_EXTERNAL_MEMORY_FEATURE_EXPORTABLE_BIT)) {
    return;
}
VkExternalMemoryBufferCreateInfo externalMemoryBufferCreateInfo = { VK_STRUCTURE_TYPE_EXTERNAL_MEMORY_BUFFER_CREATE_INFO };
externalMemoryBufferCreateInfo.handleTypes = VK_EXTERNAL_MEMORY_HANDLE_TYPE_RDMA_ADDRESS_BIT_NV;
VkBufferCreateInfo bufferCreateInfo = { VK_STRUCTURE_TYPE_BUFFER_CREATE_INFO, &externalMemoryBufferCreateInfo };
bufferCreateInfo.size = size;
bufferCreateInfo.usage = VK_BUFFER_USAGE_TRANSFER_SRC_BIT | VK_BUFFER_USAGE_TRANSFER_DST_BIT;
VkMemoryRequirements mem_reqs;
vkCreateBuffer(device, &bufferCreateInfo, NULL, &buffer);
vkGetBufferMemoryRequirements(device, buffer, &mem_reqs);
VkExportMemoryAllocateInfo exportMemoryAllocateInfo = { VK_STRUCTURE_TYPE_EXPORT_MEMORY_ALLOCATE_INFO };
exportMemoryAllocateInfo.handleTypes = VK_EXTERNAL_MEMORY_HANDLE_TYPE_RDMA_ADDRESS_BIT_NV;
// Find memory type index
uint32_t i = 0;
for (; i < VK_MAX_MEMORY_TYPES; i++) {
    if ((mem_reqs.memoryTypeBits & (1 << i)) &&
        (memoryProperties.memoryTypes[i].propertyFlags & VK_MEMORY_PROPERTY_RDMA_CAPABLE_BIT_NV)) {
        break;
    }
}
VkMemoryAllocateInfo memAllocInfo = { VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO, &exportMemoryAllocateInfo };
memAllocInfo.allocationSize = mem_reqs.size;
memAllocInfo.memoryTypeIndex = i;
vkAllocateMemory(device, &memAllocInfo, NULL, &mem);
vkBindBufferMemory(device, buffer, mem, 0);
VkMemoryGetRemoteAddressInfoNV getMemoryRemoteAddressInfo = { VK_STRUCTURE_TYPE_MEMORY_GET_REMOTE_ADDRESS_INFO_NV };
getMemoryRemoteAddressInfo.memory = mem;
getMemoryRemoteAddressInfo.handleType = VK_EXTERNAL_MEMORY_HANDLE_TYPE_RDMA_ADDRESS_BIT_NV;
VkRemoteAddressNV rdmaAddress;
vkGetMemoryRemoteAddressNV(device, &getMemoryRemoteAddressInfo, &rdmaAddress);
// address returned in 'rdmaAddress' can be used by external devices to initiate RDMA transfersDocument Notes
For more information, see the Vulkan Specification
This page is a generated document. Fixes and changes should be made to the generator scripts, not directly.