rhi: vk: Switch to cheaper VMA statistics API

Now that we upgraded to 3.0.1 vmaCalculateStatistics can be replaced
with a less-expensive call.

Change-Id: Icb444354ce9e091cf69f82aff2e2f828b8302072
Reviewed-by: Andy Nichols <andy.nichols@qt.io>

2 files changed, 12 insertions, 10 deletions

diff --git a/src/gui/rhi/qrhi.cpp b/src/gui/rhi/qrhi.cpp
index a52b953a37..701cecb3d1 100644
--- a/src/gui/rhi/qrhi.cpp
+++ b/src/gui/rhi/qrhi.cpp
@@ -7156,9 +7156,6 @@ QDebug operator<<(QDebug dbg, const QRhiStats &info)
     from the underlying memory allocator library. This gives an insight into
     the memory requirements of the active buffers and textures.
 
-    \warning Gathering some of the data may be an expensive operation, and
-    therefore the function must not be called at a high frequency.
-
     Additional data, such as the total time in milliseconds spent in graphics
     and compute pipeline creation (which usually involves shader compilation or
     cache lookups, and potentially expensive processing) is available with most
diff --git a/src/gui/rhi/qrhivulkan.cpp b/src/gui/rhi/qrhivulkan.cpp
index 8a2982fbb8..01c0b40294 100644
--- a/src/gui/rhi/qrhivulkan.cpp
+++ b/src/gui/rhi/qrhivulkan.cpp
@@ -4312,15 +4312,20 @@ QRhiDriverInfo QRhiVulkan::driverInfo() const
 
 QRhiStats QRhiVulkan::statistics()
 {
-    VmaTotalStatistics stats;
-    vmaCalculateStatistics(toVmaAllocator(allocator), &stats);
-
     QRhiStats result;
     result.totalPipelineCreationTime = totalPipelineCreationTime();
-    result.blockCount = stats.total.statistics.blockCount;
-    result.allocCount = stats.total.statistics.allocationCount;
-    result.usedBytes = stats.total.statistics.allocationBytes;
-    result.unusedBytes = stats.total.statistics.blockBytes - stats.total.statistics.allocationBytes;
+
+    VmaBudget budgets[VK_MAX_MEMORY_HEAPS];
+    vmaGetHeapBudgets(toVmaAllocator(allocator), budgets);
+
+    uint32_t count = toVmaAllocator(allocator)->GetMemoryHeapCount();
+    for (uint32_t i = 0; i < count; ++i) {
+        const VmaStatistics &stats(budgets[i].statistics);
+        result.blockCount += stats.blockCount;
+        result.allocCount += stats.allocationCount;
+        result.usedBytes += stats.allocationBytes;
+        result.unusedBytes += stats.blockBytes - stats.allocationBytes;
+    }
 
     return result;
 }