Merge pull request #4134 from cedrichansen/soaDeviation

Adding Tenure bytes deviation to modify concurrent kickoff
eclipse · Jul 25, 2019 · c4a5982 · c4a5982
2 parents cafb366 + aec40ce
commit c4a5982
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Showing 6 changed files with 44 additions and 16 deletions.
diff --git a/gc/base/GCExtensionsBase.hpp b/gc/base/GCExtensionsBase.hpp
@@ -267,6 +267,7 @@ class MM_GCExtensionsBase : public MM_BaseVirtual {
 	uintptr_t oldHeapSizeOnLastGlobalGC;
 	uintptr_t freeOldHeapSizeOnLastGlobalGC;
 	float concurrentKickoffTenuringHeadroom; /**< percentage of free memory remaining in tenure heap. Used in conjunction with free memory to determine concurrent mark kickoff */
+	float tenureBytesDeviationBoost; /**< boost factor for tenuring deviation used for concurrent mark kickoff math */
 #endif /* OMR_GC_MODRON_SCAVENGER */
 #if defined(OMR_GC_REALTIME)
 	MM_RememberedSetSATB* sATBBarrierRememberedSet; /**< The snapshot at the beginning barrier remembered set used for the write barrier */
@@ -1348,6 +1349,7 @@ class MM_GCExtensionsBase : public MM_BaseVirtual {
 		, oldHeapSizeOnLastGlobalGC(UDATA_MAX)
 		, freeOldHeapSizeOnLastGlobalGC(UDATA_MAX)
 		, concurrentKickoffTenuringHeadroom((float)0.02)
+		, tenureBytesDeviationBoost((float)2)
 #endif /* OMR_GC_MODRON_SCAVENGER */		
 #if defined(OMR_GC_REALTIME)
 		, sATBBarrierRememberedSet(NULL)

diff --git a/gc/base/Math.hpp b/gc/base/Math.hpp
@@ -113,6 +113,15 @@ class MM_Math
 
 		return number;
 	}
+
+	/**< return absolute value of a float */
+	static MMINLINE float abs(float number) {
+		if (number < 0) {
+			number = -number;
+		}
+		return number;
+	}
+
 };
 
 #endif /*MATH_HPP_*/
diff --git a/gc/base/standard/ConcurrentGC.cpp b/gc/base/standard/ConcurrentGC.cpp
@@ -1828,20 +1828,21 @@ MM_ConcurrentGC::potentialFreeSpace(MM_EnvironmentBase *env, MM_AllocateDescript
 		if (!scavengerStats->isAvailable(env)) {
 			return (uintptr_t)-1;
 		}
+
+		nurseryPromotion = scavengerStats->_avgTenureBytes == 0 ? 1: (uintptr_t)(scavengerStats->_avgTenureBytes + (env->getExtensions()->tenureBytesDeviationBoost * scavengerStats->_avgTenureBytesDeviation));
+
 #if defined(OMR_GC_LARGE_OBJECT_AREA)
 		/* Do we need to tax this allocation ? */
 		if (LOA == _meteringType) {
 			nurseryPromotion = scavengerStats->_avgTenureLOABytes == 0 ? 1 : scavengerStats->_avgTenureLOABytes;
 			currentOldFree = oldSubspace->getApproximateActiveFreeLOAMemorySize();
 			headRoom = (uintptr_t)(_extensions->concurrentKickoffTenuringHeadroom * _extensions->lastGlobalGCFreeBytesLOA);
 		} else {
-			assume0(SOA == _meteringType);
-			nurseryPromotion = scavengerStats->_avgTenureSOABytes == 0 ? 1 : scavengerStats->_avgTenureSOABytes;
+			assume0(SOA == _meteringType);			
 			currentOldFree = oldSubspace->getApproximateActiveFreeMemorySize() - oldSubspace->getApproximateActiveFreeLOAMemorySize();
 			headRoom = (uintptr_t)(_extensions->concurrentKickoffTenuringHeadroom * (_extensions->getLastGlobalGCFreeBytes() - _extensions->lastGlobalGCFreeBytesLOA));
 		}
 #else
-		nurseryPromotion = scavengerStats->_avgTenureBytes == 0 ? 1: scavengerStats->_avgTenureBytes;
 		currentOldFree = oldSubspace->getApproximateActiveFreeMemorySize();
 		headRoom = (uintptr_t)(_extensions->concurrentKickoffTenuringHeadroom * _extensions->getLastGlobalGCFreeBytes()); 
 #endif

diff --git a/gc/base/standard/Scavenger.cpp b/gc/base/standard/Scavenger.cpp
@@ -100,7 +100,7 @@
 #include "ut_omrmm.h"
 
 #define INITIAL_FREE_HISTORY_WEIGHT ((float)0.8)
-#define TENURE_BYTES_HISTORY_WEIGHT ((float)0.8)
+#define TENURE_BYTES_HISTORY_WEIGHT ((float)0.9)
 
 #define FLIP_TENURE_LARGE_SCAN 4
 #define FLIP_TENURE_LARGE_SCAN_DEFERRED 5
@@ -827,28 +827,44 @@ MM_Scavenger::calcGCStats(MM_EnvironmentStandard *env)
 		MM_ScavengerStats *scavengerGCStats;
 		scavengerGCStats = &_extensions->scavengerStats;
 		uintptr_t initialFree = env->_cycleState->_activeSubSpace->getActualActiveFreeMemorySize();
+		uintptr_t tenureAggregateBytes = 0;
+		float tenureBytesDeviation = 0;
 
 		/* First collection  ? */
 		if (scavengerGCStats->_gcCount > 1 ) {
 			scavengerGCStats->_avgInitialFree = (uintptr_t)MM_Math::weightedAverage((float)scavengerGCStats->_avgInitialFree, (float)initialFree, INITIAL_FREE_HISTORY_WEIGHT);
-			scavengerGCStats->_avgTenureBytes = (uintptr_t)MM_Math::weightedAverage((float)scavengerGCStats->_avgTenureBytes, (float)scavengerGCStats->_tenureAggregateBytes, TENURE_BYTES_HISTORY_WEIGHT);
+
 #if defined(OMR_GC_LARGE_OBJECT_AREA)
-			scavengerGCStats->_avgTenureSOABytes = (uintptr_t)MM_Math::weightedAverage((float)scavengerGCStats->_avgTenureSOABytes,
-																		(float)(scavengerGCStats->_tenureAggregateBytes - scavengerGCStats->_tenureLOABytes),
-																		TENURE_BYTES_HISTORY_WEIGHT);
+			tenureAggregateBytes = scavengerGCStats->_tenureAggregateBytes - scavengerGCStats->_tenureLOABytes;															
 			scavengerGCStats->_avgTenureLOABytes = (uintptr_t)MM_Math::weightedAverage((float)scavengerGCStats->_avgTenureLOABytes,
 																		(float)scavengerGCStats->_tenureLOABytes,
 																		TENURE_BYTES_HISTORY_WEIGHT);
-
+#else /* OMR_GC_LARGE_OBJECT_AREA */
+			tenureAggregateBytes = scavengerGCStats->_tenureAggregateBytes;
 #endif /* OMR_GC_LARGE_OBJECT_AREA */
+			scavengerGCStats->_avgTenureBytes = (uintptr_t)MM_Math::weightedAverage((float)scavengerGCStats->_avgTenureBytes, 
+																					(float)tenureAggregateBytes, 
+																					TENURE_BYTES_HISTORY_WEIGHT);
+			tenureBytesDeviation = (float)tenureAggregateBytes - scavengerGCStats->_avgTenureBytes;
+			scavengerGCStats->_avgTenureBytesDeviation = (uintptr_t)MM_Math::weightedAverage((float)scavengerGCStats->_avgTenureBytesDeviation, 
+																				MM_Math::abs(tenureBytesDeviation), 
+																				TENURE_BYTES_HISTORY_WEIGHT);																											
 		} else {
 			scavengerGCStats->_avgInitialFree = initialFree;
-			scavengerGCStats->_avgTenureBytes = scavengerGCStats->_tenureAggregateBytes;
-#if defined(OMR_GC_LARGE_OBJECT_AREA)
-			scavengerGCStats->_avgTenureSOABytes = scavengerGCStats->_tenureAggregateBytes - scavengerGCStats->_tenureLOABytes;
-			scavengerGCStats->_avgTenureLOABytes = scavengerGCStats->_tenureLOABytes;
-#endif /* OMR_GC_LARGE_OBJECT_AREA */
+
+			/* We can assume that in the first GC, about half of the objects are long lived objects, so we use this heuristic to give a rough estimate for the starting point */
+			scavengerGCStats->_avgTenureBytes = (uintptr_t)(scavengerGCStats->_flipBytes / 2);
 		}
+#if defined(OMR_GC_MODRON_CONCURRENT_MARK)
+			if (_extensions->debugConcurrentMark) {
+				OMRPORT_ACCESS_FROM_OMRPORT(env->getPortLibrary());
+            	omrtty_printf("Tenured bytes: %zu\navgTenureBytes: %zu\ntenureBytesDeviation: %f\navgTenureBytesDeviation: %zu\n",
+				tenureAggregateBytes,
+				scavengerGCStats->_avgTenureBytes,
+				tenureBytesDeviation, 
+				scavengerGCStats->_avgTenureBytesDeviation);
+			}
+#endif /* OMR_GC_MODRON_CONCURRENT_MARK */	
 	}
 }
 

diff --git a/gc/stats/ScavengerStats.cpp b/gc/stats/ScavengerStats.cpp
@@ -67,11 +67,11 @@ MM_ScavengerStats::MM_ScavengerStats()
 #endif /* J9MODRON_TGC_PARALLEL_STATISTICS */
 	,_avgInitialFree(0)
 	,_avgTenureBytes(0)
+	,_avgTenureBytesDeviation(0)
 	,_tiltRatio(0)
 	,_nextScavengeWillPercolate(false)
 #if defined(OMR_GC_LARGE_OBJECT_AREA)	
 	,_avgTenureLOABytes(0)
-	,_avgTenureSOABytes(0)
 #endif /* OMR_GC_LARGE_OBJECT_AREA */
 	,_flipDiscardBytes(0)
 	,_tenureDiscardBytes(0)

diff --git a/gc/stats/ScavengerStats.hpp b/gc/stats/ScavengerStats.hpp
@@ -103,14 +103,14 @@ class MM_ScavengerStats
 	 */ 
 	uintptr_t _avgInitialFree;
 	uintptr_t _avgTenureBytes;
+	uintptr_t _avgTenureBytesDeviation; /**< The average, weighted deviation of the tenureBytes*/
 
 	uintptr_t _tiltRatio;	/**< use to pass tiltRatio to verbose */
 
 	bool _nextScavengeWillPercolate;
 
 #if defined(OMR_GC_LARGE_OBJECT_AREA)	
 	uintptr_t _avgTenureLOABytes;
-	uintptr_t _avgTenureSOABytes;
 #endif /* OMR_GC_LARGE_OBJECT_AREA */
 
 	uintptr_t _flipDiscardBytes;		/**< Bytes of survivor discarded by copy scan cache */