/* * Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. * */ #ifndef SHARE_GC_SHARED_GC_GLOBALS_HPP #define SHARE_GC_SHARED_GC_GLOBALS_HPP #include "utilities/macros.hpp" #if INCLUDE_CMSGC #include "gc/cms/cms_globals.hpp" #endif #if INCLUDE_G1GC #include "gc/g1/g1_globals.hpp" #endif #if INCLUDE_PARALLELGC #include "gc/parallel/parallel_globals.hpp" #endif #if INCLUDE_SERIALGC #include "gc/serial/serial_globals.hpp" #endif #if INCLUDE_ZGC #include "gc/z/zFlags.hpp" #endif #define GC_FLAGS(develop, \ develop_pd, \ product, \ product_pd, \ diagnostic, \ diagnostic_pd, \ experimental, \ notproduct, \ manageable, \ product_rw, \ lp64_product, \ range, \ constraint, \ writeable) \ \ CMSGC_ONLY(GC_CMS_FLAGS( \ develop, \ develop_pd, \ product, \ product_pd, \ diagnostic, \ diagnostic_pd, \ experimental, \ notproduct, \ manageable, \ product_rw, \ lp64_product, \ range, \ constraint, \ writeable)) \ \ G1GC_ONLY(GC_G1_FLAGS( \ develop, \ develop_pd, \ product, \ product_pd, \ diagnostic, \ diagnostic_pd, \ experimental, \ notproduct, \ manageable, \ product_rw, \ lp64_product, \ range, \ constraint, \ writeable)) \ \ PARALLELGC_ONLY(GC_PARALLEL_FLAGS( \ develop, \ develop_pd, \ product, \ product_pd, \ diagnostic, \ diagnostic_pd, \ experimental, \ notproduct, \ manageable, \ product_rw, \ lp64_product, \ range, \ constraint, \ writeable)) \ \ SERIALGC_ONLY(GC_SERIAL_FLAGS( \ develop, \ develop_pd, \ product, \ product_pd, \ diagnostic, \ diagnostic_pd, \ experimental, \ notproduct, \ manageable, \ product_rw, \ lp64_product, \ range, \ constraint, \ writeable)) \ \ ZGC_ONLY(GC_Z_FLAGS( \ develop, \ develop_pd, \ product, \ product_pd, \ diagnostic, \ diagnostic_pd, \ experimental, \ notproduct, \ manageable, \ product_rw, \ lp64_product, \ range, \ constraint, \ writeable)) \ \ /* gc */ \ \ product(bool, UseConcMarkSweepGC, false, \ "Use Concurrent Mark-Sweep GC in the old generation") \ \ product(bool, UseSerialGC, false, \ "Use the Serial garbage collector") \ \ product(bool, UseG1GC, false, \ "Use the Garbage-First garbage collector") \ \ product(bool, UseParallelGC, false, \ "Use the Parallel Scavenge garbage collector") \ \ product(bool, UseParallelOldGC, false, \ "Use the Parallel Old garbage collector") \ \ experimental(bool, UseZGC, false, \ "Use the Z garbage collector") \ \ product(uint, ParallelGCThreads, 0, \ "Number of parallel threads parallel gc will use") \ constraint(ParallelGCThreadsConstraintFunc,AfterErgo) \ \ diagnostic(bool, UseSemaphoreGCThreadsSynchronization, true, \ "Use semaphore synchronization for the GC Threads, " \ "instead of synchronization based on mutexes") \ \ product(bool, UseDynamicNumberOfGCThreads, true, \ "Dynamically choose the number of threads up to a maximum of " \ "ParallelGCThreads parallel collectors will use for garbage " \ "collection work") \ \ diagnostic(bool, InjectGCWorkerCreationFailure, false, \ "Inject thread creation failures for " \ "UseDynamicNumberOfGCThreads") \ \ diagnostic(bool, ForceDynamicNumberOfGCThreads, false, \ "Force dynamic selection of the number of " \ "parallel threads parallel gc will use to aid debugging") \ \ product(size_t, HeapSizePerGCThread, ScaleForWordSize(32*M), \ "Size of heap (bytes) per GC thread used in calculating the " \ "number of GC threads") \ range((size_t)os::vm_page_size(), (size_t)max_uintx) \ \ product(uint, ConcGCThreads, 0, \ "Number of threads concurrent gc will use") \ constraint(ConcGCThreadsConstraintFunc,AfterErgo) \ \ product(uint, GCTaskTimeStampEntries, 200, \ "Number of time stamp entries per gc worker thread") \ range(1, max_jint) \ \ product(bool, AlwaysTenure, false, \ "Always tenure objects in eden (ParallelGC only)") \ \ product(bool, NeverTenure, false, \ "Never tenure objects in eden, may tenure on overflow " \ "(ParallelGC only)") \ \ product(bool, ScavengeBeforeFullGC, true, \ "Scavenge youngest generation before each full GC.") \ \ product(bool, ExplicitGCInvokesConcurrent, false, \ "A System.gc() request invokes a concurrent collection; " \ "(effective only when using concurrent collectors)") \ \ product(bool, GCLockerInvokesConcurrent, false, \ "The exit of a JNI critical section necessitating a scavenge, " \ "also kicks off a background concurrent collection") \ \ product(uintx, GCLockerEdenExpansionPercent, 5, \ "How much the GC can expand the eden by while the GC locker " \ "is active (as a percentage)") \ range(0, 100) \ \ diagnostic(uintx, GCLockerRetryAllocationCount, 2, \ "Number of times to retry allocations when " \ "blocked by the GC locker") \ range(0, max_uintx) \ \ product(uintx, ParallelGCBufferWastePct, 10, \ "Wasted fraction of parallel allocation buffer") \ range(0, 100) \ \ product(uintx, TargetPLABWastePct, 10, \ "Target wasted space in last buffer as percent of overall " \ "allocation") \ range(1, 100) \ \ product(uintx, PLABWeight, 75, \ "Percentage (0-100) used to weight the current sample when " \ "computing exponentially decaying average for ResizePLAB") \ range(0, 100) \ \ product(bool, ResizePLAB, true, \ "Dynamically resize (survivor space) promotion LAB's") \ \ product(int, ParGCArrayScanChunk, 50, \ "Scan a subset of object array and push remainder, if array is " \ "bigger than this") \ range(1, max_jint/3) \ \ product(uintx, OldPLABWeight, 50, \ "Percentage (0-100) used to weight the current sample when " \ "computing exponentially decaying average for resizing " \ "OldPLABSize") \ range(0, 100) \ \ product(bool, ResizeOldPLAB, true, \ "Dynamically resize (old gen) promotion LAB's") \ \ product(bool, AlwaysPreTouch, false, \ "Force all freshly committed pages to be pre-touched") \ \ product(size_t, PreTouchParallelChunkSize, 1 * G, \ "Per-thread chunk size for parallel memory pre-touch.") \ range(1, SIZE_MAX / 2) \ \ /* where does the range max value of (max_jint - 1) come from? */ \ product(size_t, MarkStackSizeMax, NOT_LP64(4*M) LP64_ONLY(512*M), \ "Maximum size of marking stack") \ range(1, (max_jint - 1)) \ \ product(size_t, MarkStackSize, NOT_LP64(32*K) LP64_ONLY(4*M), \ "Size of marking stack") \ constraint(MarkStackSizeConstraintFunc,AfterErgo) \ \ develop(bool, VerifyBlockOffsetArray, false, \ "Do (expensive) block offset array verification") \ \ diagnostic(bool, BlockOffsetArrayUseUnallocatedBlock, false, \ "Maintain _unallocated_block in BlockOffsetArray " \ "(currently applicable only to CMS collector)") \ \ product(intx, RefDiscoveryPolicy, 0, \ "Select type of reference discovery policy: " \ "reference-based(0) or referent-based(1)") \ range(ReferenceProcessor::DiscoveryPolicyMin, \ ReferenceProcessor::DiscoveryPolicyMax) \ \ product(bool, ParallelRefProcEnabled, false, \ "Enable parallel reference processing whenever possible") \ \ product(bool, ParallelRefProcBalancingEnabled, true, \ "Enable balancing of reference processing queues") \ \ product(uintx, InitiatingHeapOccupancyPercent, 45, \ "The percent occupancy (IHOP) of the current old generation " \ "capacity above which a concurrent mark cycle will be initiated " \ "Its value may change over time if adaptive IHOP is enabled, " \ "otherwise the value remains constant. " \ "In the latter case a value of 0 will result as frequent as " \ "possible concurrent marking cycles. A value of 100 disables " \ "concurrent marking. " \ "Fragmentation waste in the old generation is not considered " \ "free space in this calculation. (G1 collector only)") \ range(0, 100) \ \ notproduct(bool, ScavengeALot, false, \ "Force scavenge at every Nth exit from the runtime system " \ "(N=ScavengeALotInterval)") \ \ develop(bool, FullGCALot, false, \ "Force full gc at every Nth exit from the runtime system " \ "(N=FullGCALotInterval)") \ \ notproduct(bool, GCALotAtAllSafepoints, false, \ "Enforce ScavengeALot/GCALot at all potential safepoints") \ \ notproduct(bool, PromotionFailureALot, false, \ "Use promotion failure handling on every youngest generation " \ "collection") \ \ develop(uintx, PromotionFailureALotCount, 1000, \ "Number of promotion failures occurring at PLAB " \ "refill attempts (ParNew) or promotion attempts " \ "(other young collectors)") \ \ develop(uintx, PromotionFailureALotInterval, 5, \ "Total collections between promotion failures a lot") \ \ experimental(uintx, WorkStealingSleepMillis, 1, \ "Sleep time when sleep is used for yields") \ \ experimental(uintx, WorkStealingYieldsBeforeSleep, 5000, \ "Number of yields before a sleep is done during work stealing") \ \ experimental(uintx, WorkStealingHardSpins, 4096, \ "Number of iterations in a spin loop between checks on " \ "time out of hard spin") \ \ experimental(uintx, WorkStealingSpinToYieldRatio, 10, \ "Ratio of hard spins to calls to yield") \ \ develop(uintx, ObjArrayMarkingStride, 2048, \ "Number of object array elements to push onto the marking stack " \ "before pushing a continuation entry") \ \ develop(bool, MetadataAllocationFailALot, false, \ "Fail metadata allocations at intervals controlled by " \ "MetadataAllocationFailALotInterval") \ \ develop(uintx, MetadataAllocationFailALotInterval, 1000, \ "Metadata allocation failure a lot interval") \ \ notproduct(bool, ExecuteInternalVMTests, false, \ "Enable execution of internal VM tests") \ \ notproduct(bool, VerboseInternalVMTests, false, \ "Turn on logging for internal VM tests.") \ \ product(bool, ExecutingUnitTests, false, \ "Whether the JVM is running unit tests or not") \ \ product_pd(bool, UseTLAB, "Use thread-local object allocation") \ \ product_pd(bool, ResizeTLAB, \ "Dynamically resize TLAB size for threads") \ \ product(bool, ZeroTLAB, false, \ "Zero out the newly created TLAB") \ \ product(bool, TLABStats, true, \ "Provide more detailed and expensive TLAB statistics.") \ \ product_pd(bool, NeverActAsServerClassMachine, \ "Never act like a server-class machine") \ \ product(bool, AlwaysActAsServerClassMachine, false, \ "Always act like a server-class machine") \ \ product_pd(uint64_t, MaxRAM, \ "Real memory size (in bytes) used to set maximum heap size") \ range(0, 0XFFFFFFFFFFFFFFFF) \ \ product(bool, AggressiveHeap, false, \ "Optimize heap options for long-running memory intensive apps") \ \ product(size_t, ErgoHeapSizeLimit, 0, \ "Maximum ergonomically set heap size (in bytes); zero means use " \ "MaxRAM * MaxRAMPercentage / 100") \ range(0, max_uintx) \ \ product(uintx, MaxRAMFraction, 4, \ "Maximum fraction (1/n) of real memory used for maximum heap " \ "size. " \ "Deprecated, use MaxRAMPercentage instead") \ range(1, max_uintx) \ \ product(uintx, MinRAMFraction, 2, \ "Minimum fraction (1/n) of real memory used for maximum heap " \ "size on systems with small physical memory size. " \ "Deprecated, use MinRAMPercentage instead") \ range(1, max_uintx) \ \ product(uintx, InitialRAMFraction, 64, \ "Fraction (1/n) of real memory used for initial heap size. " \ "Deprecated, use InitialRAMPercentage instead") \ range(1, max_uintx) \ \ product(double, MaxRAMPercentage, 25.0, \ "Maximum percentage of real memory used for maximum heap size") \ range(0.0, 100.0) \ \ product(double, MinRAMPercentage, 50.0, \ "Minimum percentage of real memory used for maximum heap" \ "size on systems with small physical memory size") \ range(0.0, 100.0) \ \ product(double, InitialRAMPercentage, 1.5625, \ "Percentage of real memory used for initial heap size") \ range(0.0, 100.0) \ \ product(int, ActiveProcessorCount, -1, \ "Specify the CPU count the VM should use and report as active") \ \ develop(uintx, MaxVirtMemFraction, 2, \ "Maximum fraction (1/n) of virtual memory used for ergonomically "\ "determining maximum heap size") \ \ product(bool, UseAdaptiveSizePolicy, true, \ "Use adaptive generation sizing policies") \ \ product(bool, UsePSAdaptiveSurvivorSizePolicy, true, \ "Use adaptive survivor sizing policies") \ \ product(bool, UseAdaptiveGenerationSizePolicyAtMinorCollection, true, \ "Use adaptive young-old sizing policies at minor collections") \ \ product(bool, UseAdaptiveGenerationSizePolicyAtMajorCollection, true, \ "Use adaptive young-old sizing policies at major collections") \ \ product(bool, UseAdaptiveSizePolicyWithSystemGC, false, \ "Include statistics from System.gc() for adaptive size policy") \ \ product(bool, UseAdaptiveGCBoundary, false, \ "Allow young-old boundary to move") \ \ develop(intx, PSAdaptiveSizePolicyResizeVirtualSpaceAlot, -1, \ "Resize the virtual spaces of the young or old generations") \ range(-1, 1) \ \ product(uintx, AdaptiveSizeThroughPutPolicy, 0, \ "Policy for changing generation size for throughput goals") \ range(0, 1) \ \ product(uintx, AdaptiveSizePolicyInitializingSteps, 20, \ "Number of steps where heuristics is used before data is used") \ range(0, max_uintx) \ \ develop(uintx, AdaptiveSizePolicyReadyThreshold, 5, \ "Number of collections before the adaptive sizing is started") \ \ product(uintx, AdaptiveSizePolicyOutputInterval, 0, \ "Collection interval for printing information; zero means never") \ range(0, max_uintx) \ \ product(bool, UseAdaptiveSizePolicyFootprintGoal, true, \ "Use adaptive minimum footprint as a goal") \ \ product(uintx, AdaptiveSizePolicyWeight, 10, \ "Weight given to exponential resizing, between 0 and 100") \ range(0, 100) \ \ product(uintx, AdaptiveTimeWeight, 25, \ "Weight given to time in adaptive policy, between 0 and 100") \ range(0, 100) \ \ product(uintx, PausePadding, 1, \ "How much buffer to keep for pause time") \ range(0, max_juint) \ \ product(uintx, PromotedPadding, 3, \ "How much buffer to keep for promotion failure") \ range(0, max_juint) \ \ product(uintx, SurvivorPadding, 3, \ "How much buffer to keep for survivor overflow") \ range(0, max_juint) \ \ product(uintx, ThresholdTolerance, 10, \ "Allowed collection cost difference between generations") \ range(0, 100) \ \ product(uintx, AdaptiveSizePolicyCollectionCostMargin, 50, \ "If collection costs are within margin, reduce both by full " \ "delta") \ range(0, 100) \ \ product(uintx, YoungGenerationSizeIncrement, 20, \ "Adaptive size percentage change in young generation") \ range(0, 100) \ \ product(uintx, YoungGenerationSizeSupplement, 80, \ "Supplement to YoungedGenerationSizeIncrement used at startup") \ range(0, 100) \ \ product(uintx, YoungGenerationSizeSupplementDecay, 8, \ "Decay factor to YoungedGenerationSizeSupplement") \ range(1, max_uintx) \ \ product(uintx, TenuredGenerationSizeIncrement, 20, \ "Adaptive size percentage change in tenured generation") \ range(0, 100) \ \ product(uintx, TenuredGenerationSizeSupplement, 80, \ "Supplement to TenuredGenerationSizeIncrement used at startup") \ range(0, 100) \ \ product(uintx, TenuredGenerationSizeSupplementDecay, 2, \ "Decay factor to TenuredGenerationSizeIncrement") \ range(1, max_uintx) \ \ product(uintx, MaxGCPauseMillis, max_uintx - 1, \ "Adaptive size policy maximum GC pause time goal in millisecond, "\ "or (G1 Only) the maximum GC time per MMU time slice") \ range(1, max_uintx - 1) \ constraint(MaxGCPauseMillisConstraintFunc,AfterErgo) \ \ product(uintx, GCPauseIntervalMillis, 0, \ "Time slice for MMU specification") \ constraint(GCPauseIntervalMillisConstraintFunc,AfterErgo) \ \ product(uintx, MaxGCMinorPauseMillis, max_uintx, \ "Adaptive size policy maximum GC minor pause time goal " \ "in millisecond") \ range(0, max_uintx) \ \ product(uintx, GCTimeRatio, 99, \ "Adaptive size policy application time to GC time ratio") \ range(0, max_juint) \ \ product(uintx, AdaptiveSizeDecrementScaleFactor, 4, \ "Adaptive size scale down factor for shrinking") \ range(1, max_uintx) \ \ product(bool, UseAdaptiveSizeDecayMajorGCCost, true, \ "Adaptive size decays the major cost for long major intervals") \ \ product(uintx, AdaptiveSizeMajorGCDecayTimeScale, 10, \ "Time scale over which major costs decay") \ range(0, max_uintx) \ \ product(uintx, MinSurvivorRatio, 3, \ "Minimum ratio of young generation/survivor space size") \ range(3, max_uintx) \ \ product(uintx, InitialSurvivorRatio, 8, \ "Initial ratio of young generation/survivor space size") \ range(0, max_uintx) \ \ product(size_t, BaseFootPrintEstimate, 256*M, \ "Estimate of footprint other than Java Heap") \ range(0, max_uintx) \ \ product(bool, UseGCOverheadLimit, true, \ "Use policy to limit of proportion of time spent in GC " \ "before an OutOfMemory error is thrown") \ \ product(uintx, GCTimeLimit, 98, \ "Limit of the proportion of time spent in GC before " \ "an OutOfMemoryError is thrown (used with GCHeapFreeLimit)") \ range(0, 100) \ \ product(uintx, GCHeapFreeLimit, 2, \ "Minimum percentage of free space after a full GC before an " \ "OutOfMemoryError is thrown (used with GCTimeLimit)") \ range(0, 100) \ \ develop(uintx, AdaptiveSizePolicyGCTimeLimitThreshold, 5, \ "Number of consecutive collections before gc time limit fires") \ range(1, max_uintx) \ \ product(intx, PrefetchCopyIntervalInBytes, -1, \ "How far ahead to prefetch destination area (<= 0 means off)") \ range(-1, max_jint) \ \ product(intx, PrefetchScanIntervalInBytes, -1, \ "How far ahead to prefetch scan area (<= 0 means off)") \ range(-1, max_jint) \ \ product(intx, PrefetchFieldsAhead, -1, \ "How many fields ahead to prefetch in oop scan (<= 0 means off)") \ range(-1, max_jint) \ \ diagnostic(bool, VerifyDuringStartup, false, \ "Verify memory system before executing any Java code " \ "during VM initialization") \ \ diagnostic(bool, VerifyBeforeExit, trueInDebug, \ "Verify system before exiting") \ \ diagnostic(bool, VerifyBeforeGC, false, \ "Verify memory system before GC") \ \ diagnostic(bool, VerifyAfterGC, false, \ "Verify memory system after GC") \ \ diagnostic(bool, VerifyDuringGC, false, \ "Verify memory system during GC (between phases)") \ \ diagnostic(ccstrlist, VerifyGCType, "", \ "GC type(s) to verify when Verify*GC is enabled." \ "Available types are collector specific.") \ \ diagnostic(ccstrlist, VerifySubSet, "", \ "Memory sub-systems to verify when Verify*GC flag(s) " \ "are enabled. One or more sub-systems can be specified " \ "in a comma separated string. Sub-systems are: " \ "threads, heap, symbol_table, string_table, codecache, " \ "dictionary, classloader_data_graph, metaspace, jni_handles, " \ "codecache_oops") \ \ diagnostic(bool, GCParallelVerificationEnabled, true, \ "Enable parallel memory system verification") \ \ diagnostic(bool, DeferInitialCardMark, false, \ "When +ReduceInitialCardMarks, explicitly defer any that " \ "may arise from new_pre_store_barrier") \ \ product(bool, UseCondCardMark, false, \ "Check for already marked card before updating card table") \ \ diagnostic(bool, VerifyRememberedSets, false, \ "Verify GC remembered sets") \ \ diagnostic(bool, VerifyObjectStartArray, true, \ "Verify GC object start array if verify before/after") \ \ product(bool, DisableExplicitGC, false, \ "Ignore calls to System.gc()") \ \ product(bool, BindGCTaskThreadsToCPUs, false, \ "Bind GCTaskThreads to CPUs if possible") \ \ product(bool, UseGCTaskAffinity, false, \ "Use worker affinity when asking for GCTasks") \ \ product(bool, PrintGC, false, \ "Print message at garbage collection. " \ "Deprecated, use -Xlog:gc instead.") \ \ product(bool, PrintGCDetails, false, \ "Print more details at garbage collection. " \ "Deprecated, use -Xlog:gc* instead.") \ \ develop(intx, ConcGCYieldTimeout, 0, \ "If non-zero, assert that GC threads yield within this " \ "number of milliseconds") \ range(0, max_intx) \ \ notproduct(intx, ScavengeALotInterval, 1, \ "Interval between which scavenge will occur with +ScavengeALot") \ \ notproduct(intx, FullGCALotInterval, 1, \ "Interval between which full gc will occur with +FullGCALot") \ \ notproduct(intx, FullGCALotStart, 0, \ "For which invocation to start FullGCAlot") \ \ notproduct(intx, FullGCALotDummies, 32*K, \ "Dummy object allocated with +FullGCALot, forcing all objects " \ "to move") \ \ /* gc parameters */ \ product(size_t, InitialHeapSize, 0, \ "Initial heap size (in bytes); zero means use ergonomics") \ constraint(InitialHeapSizeConstraintFunc,AfterErgo) \ \ product(size_t, MaxHeapSize, ScaleForWordSize(96*M), \ "Maximum heap size (in bytes)") \ constraint(MaxHeapSizeConstraintFunc,AfterErgo) \ \ product(size_t, OldSize, ScaleForWordSize(4*M), \ "Initial tenured generation size (in bytes)") \ range(0, max_uintx) \ \ product(size_t, NewSize, ScaleForWordSize(1*M), \ "Initial new generation size (in bytes)") \ constraint(NewSizeConstraintFunc,AfterErgo) \ \ product(size_t, MaxNewSize, max_uintx, \ "Maximum new generation size (in bytes), max_uintx means set " \ "ergonomically") \ range(0, max_uintx) \ \ product_pd(size_t, HeapBaseMinAddress, \ "OS specific low limit for heap base address") \ constraint(HeapBaseMinAddressConstraintFunc,AfterErgo) \ \ product(size_t, PretenureSizeThreshold, 0, \ "Maximum size in bytes of objects allocated in DefNew " \ "generation; zero means no maximum") \ range(0, max_uintx) \ \ product(size_t, MinTLABSize, 2*K, \ "Minimum allowed TLAB size (in bytes)") \ range(1, max_uintx/2) \ constraint(MinTLABSizeConstraintFunc,AfterMemoryInit) \ \ product(size_t, TLABSize, 0, \ "Starting TLAB size (in bytes); zero means set ergonomically") \ constraint(TLABSizeConstraintFunc,AfterMemoryInit) \ \ product(size_t, YoungPLABSize, 4096, \ "Size of young gen promotion LAB's (in HeapWords)") \ constraint(YoungPLABSizeConstraintFunc,AfterMemoryInit) \ \ product(size_t, OldPLABSize, 1024, \ "Size of old gen promotion LAB's (in HeapWords), or Number " \ "of blocks to attempt to claim when refilling CMS LAB's") \ constraint(OldPLABSizeConstraintFunc,AfterMemoryInit) \ \ product(uintx, TLABAllocationWeight, 35, \ "Allocation averaging weight") \ range(0, 100) \ \ /* Limit the lower bound of this flag to 1 as it is used */ \ /* in a division expression. */ \ product(uintx, TLABWasteTargetPercent, 1, \ "Percentage of Eden that can be wasted") \ range(1, 100) \ \ product(uintx, TLABRefillWasteFraction, 64, \ "Maximum TLAB waste at a refill (internal fragmentation)") \ range(1, max_juint) \ \ product(uintx, TLABWasteIncrement, 4, \ "Increment allowed waste at slow allocation") \ range(0, max_jint) \ constraint(TLABWasteIncrementConstraintFunc,AfterMemoryInit) \ \ product(uintx, SurvivorRatio, 8, \ "Ratio of eden/survivor space size") \ range(1, max_uintx-2) \ constraint(SurvivorRatioConstraintFunc,AfterMemoryInit) \ \ product(uintx, NewRatio, 2, \ "Ratio of old/new generation sizes") \ range(0, max_uintx-1) \ \ product_pd(size_t, NewSizeThreadIncrease, \ "Additional size added to desired new generation size per " \ "non-daemon thread (in bytes)") \ range(0, max_uintx) \ \ product(uintx, QueuedAllocationWarningCount, 0, \ "Number of times an allocation that queues behind a GC " \ "will retry before printing a warning") \ range(0, max_uintx) \ \ diagnostic(uintx, VerifyGCStartAt, 0, \ "GC invoke count where +VerifyBefore/AfterGC kicks in") \ range(0, max_uintx) \ \ diagnostic(intx, VerifyGCLevel, 0, \ "Generation level at which to start +VerifyBefore/AfterGC") \ range(0, 1) \ \ product(uintx, MaxTenuringThreshold, 15, \ "Maximum value for tenuring threshold") \ range(0, markOopDesc::max_age + 1) \ constraint(MaxTenuringThresholdConstraintFunc,AfterErgo) \ \ product(uintx, InitialTenuringThreshold, 7, \ "Initial value for tenuring threshold") \ range(0, markOopDesc::max_age + 1) \ constraint(InitialTenuringThresholdConstraintFunc,AfterErgo) \ \ product(uintx, TargetSurvivorRatio, 50, \ "Desired percentage of survivor space used after scavenge") \ range(0, 100) \ \ product(uintx, MarkSweepDeadRatio, 5, \ "Percentage (0-100) of the old gen allowed as dead wood. " \ "Serial mark sweep treats this as both the minimum and maximum " \ "value. " \ "CMS uses this value only if it falls back to mark sweep. " \ "Par compact uses a variable scale based on the density of the " \ "generation and treats this as the maximum value when the heap " \ "is either completely full or completely empty. Par compact " \ "also has a smaller default value; see arguments.cpp.") \ range(0, 100) \ \ product(uint, MarkSweepAlwaysCompactCount, 4, \ "How often should we fully compact the heap (ignoring the dead " \ "space parameters)") \ range(1, max_juint) \ \ develop(uintx, GCExpandToAllocateDelayMillis, 0, \ "Delay between expansion and allocation (in milliseconds)") \ \ product(uintx, GCDrainStackTargetSize, 64, \ "Number of entries we will try to leave on the stack " \ "during parallel gc") \ range(0, max_juint) #endif // SHARE_GC_SHARED_GC_GLOBALS_HPP