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gc_globals.hpp
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gc_globals.hpp
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/*
* Copyright (c) 1997, 2020, 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 "runtime/globals_shared.hpp"
#include "utilities/macros.hpp"
#if INCLUDE_EPSILONGC
#include "gc/epsilon/epsilon_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_SHENANDOAHGC
#include "gc/shenandoah/shenandoah_globals.hpp"
#endif
#if INCLUDE_ZGC
#include "gc/z/z_globals.hpp"
#endif
#define GC_FLAGS(develop, \
develop_pd, \
product, \
product_pd, \
diagnostic, \
diagnostic_pd, \
experimental, \
notproduct, \
manageable, \
product_rw, \
lp64_product, \
range, \
constraint) \
\
EPSILONGC_ONLY(GC_EPSILON_FLAGS( \
develop, \
develop_pd, \
product, \
product_pd, \
diagnostic, \
diagnostic_pd, \
experimental, \
notproduct, \
manageable, \
product_rw, \
lp64_product, \
range, \
constraint)) \
\
G1GC_ONLY(GC_G1_FLAGS( \
develop, \
develop_pd, \
product, \
product_pd, \
diagnostic, \
diagnostic_pd, \
experimental, \
notproduct, \
manageable, \
product_rw, \
lp64_product, \
range, \
constraint)) \
\
PARALLELGC_ONLY(GC_PARALLEL_FLAGS( \
develop, \
develop_pd, \
product, \
product_pd, \
diagnostic, \
diagnostic_pd, \
experimental, \
notproduct, \
manageable, \
product_rw, \
lp64_product, \
range, \
constraint)) \
\
SERIALGC_ONLY(GC_SERIAL_FLAGS( \
develop, \
develop_pd, \
product, \
product_pd, \
diagnostic, \
diagnostic_pd, \
experimental, \
notproduct, \
manageable, \
product_rw, \
lp64_product, \
range, \
constraint)) \
\
SHENANDOAHGC_ONLY(GC_SHENANDOAH_FLAGS( \
develop, \
develop_pd, \
product, \
product_pd, \
diagnostic, \
diagnostic_pd, \
experimental, \
notproduct, \
manageable, \
product_rw, \
lp64_product, \
range, \
constraint)) \
\
ZGC_ONLY(GC_Z_FLAGS( \
develop, \
develop_pd, \
product, \
product_pd, \
diagnostic, \
diagnostic_pd, \
experimental, \
notproduct, \
manageable, \
product_rw, \
lp64_product, \
range, \
constraint)) \
\
/* gc */ \
\
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 garbage collector.") \
\
experimental(bool, UseEpsilonGC, false, \
"Use the Epsilon (no-op) garbage collector") \
\
product(bool, UseZGC, false, \
"Use the Z garbage collector") \
\
product(bool, UseShenandoahGC, false, \
"Use the Shenandoah garbage collector") \
\
product(uint, ParallelGCThreads, 0, \
"Number of parallel threads parallel gc will use") \
constraint(ParallelGCThreadsConstraintFunc,AfterErgo) \
\
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") \
\
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(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(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(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) \
range(1, (max_jint - 1)) \
\
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") \
\
experimental(size_t, ReferencesPerThread, 1000, \
"Ergonomically start one thread for this amount of " \
"references for reference processing if " \
"ParallelRefProcEnabled is true. Specify 0 to disable and " \
"use all threads.") \
\
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 promotion " \
"attempts at 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") \
\
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") \
\
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, GCOverheadLimitThreshold, 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, 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, MinHeapSize, 0, \
"Minimum heap size (in bytes); zero means use ergonomics") \
constraint(MinHeapSizeConstraintFunc,AfterErgo) \
\
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) \
\
manageable(size_t, SoftMaxHeapSize, 0, \
"Soft limit for maximum heap size (in bytes)") \
constraint(SoftMaxHeapSizeConstraintFunc,AfterMemoryInit) \
\
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)") \
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, markWord::max_age + 1) \
constraint(MaxTenuringThresholdConstraintFunc,AfterErgo) \
\
product(uintx, InitialTenuringThreshold, 7, \
"Initial value for tenuring threshold") \
range(0, markWord::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. " \
"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