Merge pull request #4780 from amicic/split_param_defaults

Scan Queue splitting defaults
eclipse · Jan 29, 2020 · 6d5cab8 · 6d5cab8
2 parents ba0338d + 6b41925
commit 6d5cab8
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Showing 3 changed files with 13 additions and 19 deletions.
diff --git a/gc/base/Configuration.cpp b/gc/base/Configuration.cpp
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 1991, 2019 IBM Corp. and others
+ * Copyright (c) 1991, 2020 IBM Corp. and others
  *
  * This program and the accompanying materials are made available under
  * the terms of the Eclipse Public License 2.0 which accompanies this
@@ -448,35 +448,27 @@ MM_Configuration::initializeGCParameters(MM_EnvironmentBase* env)
 
 	/* TODO 108399: May need to adjust -Xmn*, -Xmo* values here if not fully specified on startup options */
 
+	Assert_MM_true(0 < extensions->gcThreadCount);
+
 	/* initialize packet lock splitting factor */
 	if (0 == extensions->packetListSplit) {
-		if (16 >= extensions->gcThreadCount) {
-			extensions->packetListSplit = extensions->gcThreadCount;
-		} else if (32 >= extensions->gcThreadCount) {
-			extensions->packetListSplit = 16 + ((extensions->gcThreadCount - 16) / 4);
-		} else {
-			extensions->packetListSplit = 20 + ((extensions->gcThreadCount - 32) / 8);
-		}
+		extensions->packetListSplit = (extensions->gcThreadCount - 1) / 8  +  1;
 	}
 
+#if defined(OMR_GC_MODRON_SCAVENGER)
 	/* initialize scan cache lock splitting factor */
 	if (0 == extensions->cacheListSplit) {
-		if (16 >= extensions->gcThreadCount) {
-			extensions->cacheListSplit = extensions->gcThreadCount;
-		} else if (32 >= extensions->gcThreadCount) {
-			extensions->cacheListSplit = 16 + ((extensions->gcThreadCount - 16) / 4);
-		} else {
-			extensions->cacheListSplit = 20 + ((extensions->gcThreadCount - 32) / 8);
-		}
+		extensions->cacheListSplit = (extensions->gcThreadCount - 1) / 8  +  1;
 	}
+#endif /* OMR_GC_MODRON_SCAVENGER */
 
 	/* initialize default split freelist split amount */
 	if (0 == extensions->splitFreeListSplitAmount) {
-	#if defined(OMR_GC_MODRON_SCAVENGER)
+#if defined(OMR_GC_MODRON_SCAVENGER)
 		if (extensions->scavengerEnabled) {
 			extensions->splitFreeListSplitAmount = (extensions->gcThreadCount - 1) / 8  +  1;
 		} else
-	#endif /* OMR_GC_MODRON_SCAVENGER */
+#endif /* OMR_GC_MODRON_SCAVENGER */
 		{
 			OMRPORT_ACCESS_FROM_OMRPORT(env->getPortLibrary());
 			extensions->splitFreeListSplitAmount = (omrsysinfo_get_number_CPUs_by_type(OMRPORT_CPU_ONLINE) - 1) / 8  +  1;

diff --git a/gc/base/GCExtensionsBase.hpp b/gc/base/GCExtensionsBase.hpp
@@ -379,7 +379,6 @@ class MM_GCExtensionsBase : public MM_BaseVirtual {
 
 	uintptr_t workpacketCount; /**< this value is ONLY set if -Xgcworkpackets is specified - otherwise the workpacket count is determined heuristically */
 	uintptr_t packetListSplit; /**< the number of ways to split packet lists, set by -XXgc:packetListLockSplit=, or determined heuristically based on the number of GC threads */
-	uintptr_t cacheListSplit; /**< the number of ways to split scanCache lists, set by -XXgc:cacheListLockSplit=, or determined heuristically based on the number of GC threads */
 
 	uintptr_t markingArraySplitMaximumAmount; /**< maximum number of elements to split array scanning work in marking scheme */
 	uintptr_t markingArraySplitMinimumAmount; /**< minimum number of elements to split array scanning work in marking scheme */
@@ -456,6 +455,7 @@ class MM_GCExtensionsBase : public MM_BaseVirtual {
 	bool scvTenureStrategyHistory; /**< Flag for enabling the History scavenger tenure strategy. */
 	bool scavengerEnabled;
 	bool scavengerRsoScanUnsafe;
+	uintptr_t cacheListSplit; /**< the number of ways to split scanCache lists, set by -XXgc:cacheListLockSplit=, or determined heuristically based on the number of GC threads */
 #if defined(OMR_GC_CONCURRENT_SCAVENGER)
 	bool softwareRangeCheckReadBarrier; /**< enable software read barrier instead of hardware guarded loads when running with CS */
 	bool concurrentScavenger; /**< CS enabled/disabled flag */
@@ -1450,7 +1450,6 @@ class MM_GCExtensionsBase : public MM_BaseVirtual {
 		, useGCStartupHints(true)	
 		, workpacketCount(0) /* only set if -Xgcworkpackets specified */
 		, packetListSplit(0)
-		, cacheListSplit(0)
 		, markingArraySplitMaximumAmount(DEFAULT_ARRAY_SPLIT_MAXIMUM_SIZE)
 		, markingArraySplitMinimumAmount(DEFAULT_ARRAY_SPLIT_MINIMUM_SIZE)
 		, rootScannerStatsEnabled(false)
@@ -1512,6 +1511,7 @@ class MM_GCExtensionsBase : public MM_BaseVirtual {
 		, scvTenureStrategyHistory(true)
 		, scavengerEnabled(false)
 		, scavengerRsoScanUnsafe(false)
+		, cacheListSplit(0)
 #if defined(OMR_GC_CONCURRENT_SCAVENGER)
 		, softwareRangeCheckReadBarrier(false)
 		, concurrentScavenger(false)

diff --git a/gc/verbose/VerboseHandlerOutput.cpp b/gc/verbose/VerboseHandlerOutput.cpp
@@ -310,7 +310,9 @@ MM_VerboseHandlerOutput::handleInitialized(J9HookInterface** hook, uintptr_t eve
 	}
 
 	writer->formatAndOutput(env, 1, "<attribute name=\"packetListSplit\" value=\"%zu\" />", _extensions->packetListSplit);
+#if defined(OMR_GC_MODRON_SCAVENGER)
 	writer->formatAndOutput(env, 1, "<attribute name=\"cacheListSplit\" value=\"%zu\" />", _extensions->cacheListSplit);
+#endif /* OMR_GC_MODRON_SCAVENGER */
 	writer->formatAndOutput(env, 1, "<attribute name=\"splitFreeListSplitAmount\" value=\"%zu\" />", _extensions->splitFreeListSplitAmount);
 	writer->formatAndOutput(env, 1, "<attribute name=\"numaNodes\" value=\"%zu\" />", event->numaNodes);