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<title>Vulkan Memory Allocator: Statistics</title>
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<li class="navelem"><a class="el" href="index.html">Vulkan Memory Allocator</a></li> </ul>
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<div class="headertitle"><div class="title">Statistics </div></div>
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<div class="textblock"><p >This library contains several functions that return information about its internal state, especially the amount of memory allocated from Vulkan.</p>
<h1><a class="anchor" id="statistics_numeric_statistics"></a>
Numeric statistics</h1>
<p >If you need to obtain basic statistics about memory usage per heap, together with current budget, you can call function <a class="el" href="group__group__stats.html#ga9f88db9d46a432c0ad7278cecbc5eaa7" title="Retrieves information about current memory usage and budget for all memory heaps.">vmaGetHeapBudgets()</a> and inspect structure <a class="el" href="struct_vma_budget.html" title="Statistics of current memory usage and available budget for a specific memory heap.">VmaBudget</a>. This is useful to keep track of memory usage and stay withing budget (see also <a class="el" href="staying_within_budget.html">Staying within budget</a>). Example:</p>
<div class="fragment"><div class="line">uint32_t heapIndex = ...</div>
<div class="line"> </div>
<div class="line">VmaBudget budgets[VK_MAX_MEMORY_HEAPS];</div>
<div class="line"><a class="code hl_function" href="group__group__stats.html#ga9f88db9d46a432c0ad7278cecbc5eaa7">vmaGetHeapBudgets</a>(allocator, budgets);</div>
<div class="line"> </div>
<div class="line">printf(<span class="stringliteral">"My heap currently has %u allocations taking %llu B,\n"</span>,</div>
<div class="line"> budgets[heapIndex].statistics.allocationCount,</div>
<div class="line"> budgets[heapIndex].statistics.allocationBytes);</div>
<div class="line">printf(<span class="stringliteral">"allocated out of %u Vulkan device memory blocks taking %llu B,\n"</span>,</div>
<div class="line"> budgets[heapIndex].statistics.blockCount,</div>
<div class="line"> budgets[heapIndex].statistics.blockBytes);</div>
<div class="line">printf(<span class="stringliteral">"Vulkan reports total usage %llu B with budget %llu B.\n"</span>,</div>
<div class="line"> budgets[heapIndex].usage,</div>
<div class="line"> budgets[heapIndex].budget);</div>
<div class="ttc" id="agroup__group__stats_html_ga9f88db9d46a432c0ad7278cecbc5eaa7"><div class="ttname"><a href="group__group__stats.html#ga9f88db9d46a432c0ad7278cecbc5eaa7">vmaGetHeapBudgets</a></div><div class="ttdeci">void vmaGetHeapBudgets(VmaAllocator allocator, VmaBudget *pBudgets)</div><div class="ttdoc">Retrieves information about current memory usage and budget for all memory heaps.</div></div>
</div><!-- fragment --><p >You can query for more detailed statistics per memory heap, type, and totals, including minimum and maximum allocation size and unused range size, by calling function <a class="el" href="group__group__stats.html#ga36f3484de7aa6cd6edc4de9edfa0ff59" title="Retrieves statistics from current state of the Allocator.">vmaCalculateStatistics()</a> and inspecting structure <a class="el" href="struct_vma_total_statistics.html" title="General statistics from current state of the Allocator - total memory usage across all memory heaps a...">VmaTotalStatistics</a>. This function is slower though, as it has to traverse all the internal data structures, so it should be used only for debugging purposes.</p>
<p >You can query for statistics of a custom pool using function <a class="el" href="group__group__stats.html#ga34d8e7d83774eed0caee5c5ae88e217d" title="Retrieves statistics of existing VmaPool object.">vmaGetPoolStatistics()</a> or <a class="el" href="group__group__stats.html#ga50ba0eb25d2b363b792be4645ca7a380" title="Retrieves detailed statistics of existing VmaPool object.">vmaCalculatePoolStatistics()</a>.</p>
<p >You can query for information about a specific allocation using function <a class="el" href="group__group__alloc.html#ga86dd08aba8633bfa4ad0df2e76481d8b" title="Returns current information about specified allocation.">vmaGetAllocationInfo()</a>. It fill structure <a class="el" href="struct_vma_allocation_info.html" title="Parameters of VmaAllocation objects, that can be retrieved using function vmaGetAllocationInfo().">VmaAllocationInfo</a>.</p>
<h1><a class="anchor" id="statistics_json_dump"></a>
JSON dump</h1>
<p >You can dump internal state of the allocator to a string in JSON format using function <a class="el" href="group__group__stats.html#gaa4fee7eb5253377599ef4fd38c93c2a0" title="Builds and returns statistics as a null-terminated string in JSON format.">vmaBuildStatsString()</a>. The result is guaranteed to be correct JSON. It uses ANSI encoding. Any strings provided by user (see <a class="el" href="allocation_annotation.html#allocation_names">Allocation names</a>) 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 treated as using this encoding. It must be freed using function <a class="el" href="group__group__stats.html#ga3104eb30d8122c84dd8541063f145288">vmaFreeStatsString()</a>.</p>
<p >The format of this JSON 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 appropriate mention in changelog.</p>
<p >The JSON string contains all the data that can be obtained using <a class="el" href="group__group__stats.html#ga36f3484de7aa6cd6edc4de9edfa0ff59" title="Retrieves statistics from current state of the Allocator.">vmaCalculateStatistics()</a>. 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. </p>
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