Add workaround for zombie memory bug in Intel Iris Plus Graphics
driver when repeatedly retrieving GPU counter sets.
diff --git a/Docs/Whats_New.md b/Docs/Whats_New.md
index 0519187..d35900a 100644
--- a/Docs/Whats_New.md
+++ b/Docs/Whats_New.md
@@ -30,6 +30,7 @@
used by a subsequent pipeline that does not use push constants.
- Fix error on some Apple GPU's where a `vkCmdTimestampQuery()` after a renderpass was
writing timestamp before renderpass activity was complete.
+- Work around zombie memory bug in Intel Iris Plus Graphics driver when repeatedly retrieving GPU counter sets.
- Update to latest SPIRV-Cross:
- MSL: Emit interface block members of array length 1 as arrays instead of scalars.
diff --git a/MoltenVK/MoltenVK/GPUObjects/MVKDevice.mm b/MoltenVK/MoltenVK/GPUObjects/MVKDevice.mm
index 88ef958..a929eeb 100644
--- a/MoltenVK/MoltenVK/GPUObjects/MVKDevice.mm
+++ b/MoltenVK/MoltenVK/GPUObjects/MVKDevice.mm
@@ -2812,6 +2812,14 @@
@autoreleasepool {
if (_metalFeatures.counterSamplingPoints) {
NSArray<id<MTLCounterSet>>* counterSets = _mtlDevice.counterSets;
+
+ // Workaround for a bug in Intel Iris Plus Graphics driver where the counterSets
+ // array is not properly retained internally, and becomes a zombie when counterSets
+ // is called more than once, which occurs when an app creates more than one VkInstance.
+ // This workaround will cause a very small memory leak on systems that do not have this
+ // bug, so we apply the workaround only when absolutely needed for specific devices.
+ if (_properties.vendorID == kIntelVendorId && _properties.deviceID == 0x8a53) { [counterSets retain]; }
+
for (id<MTLCounterSet> cs in counterSets){
NSString* csName = cs.name;
if ( [csName caseInsensitiveCompare: MTLCommonCounterSetTimestamp] == NSOrderedSame) {
