| // Copyright 2018-2021 The Khronos Group, Inc. |
| // |
| // SPDX-License-Identifier: CC-BY-4.0 |
| |
| include::{generated}/meta/{refprefix}VK_EXT_memory_budget.txt[] |
| |
| === Other Extension Metadata |
| |
| *Last Modified Date*:: |
| 2018-10-08 |
| *Contributors*:: |
| - Jeff Bolz, NVIDIA |
| - Jeff Juliano, NVIDIA |
| |
| === Description |
| |
| While running a Vulkan application, other processes on the machine might |
| also be attempting to use the same device memory, which can pose problems. |
| This extension adds support for querying the amount of memory used and the |
| total memory budget for a memory heap. |
| The values returned by this query are implementation-dependent and can |
| depend on a variety of factors including operating system and system load. |
| |
| The slink:VkPhysicalDeviceMemoryBudgetPropertiesEXT::pname:heapBudget values |
| can be used as a guideline for how much total memory from each heap the |
| **current process** can use at any given time, before allocations may start |
| failing or causing performance degradation. |
| The values may change based on other activity in the system that is outside |
| the scope and control of the Vulkan implementation. |
| |
| The slink:VkPhysicalDeviceMemoryBudgetPropertiesEXT::pname:heapUsage will |
| display the **current process** estimated heap usage. |
| |
| With this information, the idea is for an application at some interval (once |
| per frame, per few seconds, etc) to query pname:heapBudget and |
| pname:heapUsage. |
| From here the application can notice if it is over budget and decide how it |
| wants to handle the memory situation (free it, move to host memory, changing |
| mipmap levels, etc). |
| This extension is designed to be used in concert with |
| `apiext:VK_EXT_memory_priority` to help with this part of memory management. |
| |
| include::{generated}/interfaces/VK_EXT_memory_budget.txt[] |
| |
| === Version History |
| |
| * Revision 1, 2018-10-08 (Jeff Bolz) |
| - Initial revision |
