Statistics

This library contains functions that return information about its internal state, especially the amount of memory allocated from Vulkan. Please keep in mind that these functions need to traverse all internal data structures to gather these information, so they may be quite time-consuming. Don't call them too often.

Numeric statistics

You can query for overall statistics of the allocator using function vmaCalculateStats(). Information are returned using structure VmaStats. It contains VmaStatInfo - number of allocated blocks, number of allocations (occupied ranges in these blocks), number of unused (free) ranges in these blocks, number of bytes used and unused (but still allocated from Vulkan) and other information. They are summed across memory heaps, memory types and total for whole allocator.

You can query for statistics of a custom pool using function vmaGetPoolStats(). Information are returned using structure VmaPoolStats.

You can query for information about specific allocation using function vmaGetAllocationInfo(). It fill structure VmaAllocationInfo.

JSON dump

You can dump internal state of the allocator to a string in JSON format using function vmaBuildStatsString(). The result is guaranteed to be correct JSON. It uses ANSI encoding. Any strings provided by user (see Allocation names) are copied as-is and properly escaped for JSON, so if they use UTF-8, ISO-8859-2 or any other encoding, this JSON string can be treted as using this encoding. It must be freed using function vmaFreeStatsString().

The format of this string is not part of official documentation of the library, but it will not change in backward-incompatible way without increasing library major version number and mention in changelog.

The string contains all the data that can be obtained using vmaCalculateStats(). It can also contain detailed map of allocated memory blocks and their regions - free and occupied by allocations. This allows e.g. to visualize the memory or assess fragmentation.