Java 查看实验性质的 JVM 命令行参数

命令

使用-XX:+UnlockExperimentalVMOptions解锁实验性质的命令行参数，通过-XX:+PrintFlagsFinal参数查看参数。

java -XX:+UnlockExperimentalVMOptions -XX:+PrintFlagsFinal -version | grep experimental

输出

❯ java -XX:+UnlockExperimentalVMOptions -XX:+PrintFlagsFinal -version | grep experimental
ccstrlist AOTLibrary                               =                                      {experimental} {default}
     bool AggressiveUnboxing                       = false                             {C2 experimental} {default}
     bool AlwaysAtomicAccesses                     = false                                {experimental} {default}
     bool AlwaysSafeConstructors                   = false                                {experimental} {default}
   size_t ArrayAllocatorMallocLimit                = 18446744073709551615                 {experimental} {default}
     bool BootstrapJVMCI                           = false                          {JVMCI experimental} {default}
     bool DisablePrimordialThreadGuardPages        = false                                {experimental} {default}
     bool EagerJVMCI                               = false                          {JVMCI experimental} {default}
     intx EmitSync                                 = 0                                    {experimental} {default}
     bool EnableJVMCI                              = false                          {JVMCI experimental} {default}
     bool EpsilonElasticTLAB                       = true                                 {experimental} {default}
     bool EpsilonElasticTLABDecay                  = true                                 {experimental} {default}
   size_t EpsilonMaxTLABSize                       = 4194304                              {experimental} {default}
   size_t EpsilonMinHeapExpand                     = 134217728                            {experimental} {default}
   size_t EpsilonPrintHeapSteps                    = 20                                   {experimental} {default}
   size_t EpsilonTLABDecayTime                     = 1000                                 {experimental} {default}
   double EpsilonTLABElasticity                    = 1.100000                             {experimental} {default}
   size_t EpsilonUpdateCountersStep                = 1048576                              {experimental} {default}
   size_t G1AdaptiveIHOPNumInitialSamples          = 3                                    {experimental} {default}
     bool G1EagerReclaimHumongousObjects           = true                                 {experimental} {default}
     bool G1EagerReclaimHumongousObjectsWithStaleRefs  = true                             {experimental} {default}
     intx G1ExpandByPercentOfAvailable             = 20                                   {experimental} {default}
   double G1LastPLABAverageOccupancy               = 50.000000                            {experimental} {default}
    uintx G1MaxNewSizePercent                      = 60                                   {experimental} {default}
    uintx G1MixedGCLiveThresholdPercent            = 85                                   {experimental} {default}
    uintx G1NewSizePercent                         = 5                                    {experimental} {default}
    uintx G1OldCSetRegionThresholdPercent          = 10                                   {experimental} {default}
     bool G1PretouchAuxiliaryMemory                = false                                {experimental} {default}
   size_t G1RebuildRemSetChunkSize                 = 262144                               {experimental} {default}
     bool G1UseReferencePrecleaning                = true                                 {experimental} {default}
     intx JVMCICounterSize                         = 0                              {JVMCI experimental} {default}
     bool JVMCICountersExcludeCompiler             = true                           {JVMCI experimental} {default}
     intx JVMCIHostThreads                         = 1                              {JVMCI experimental} {default}
     intx JVMCINMethodSizeLimit                    = 655360                         {JVMCI experimental} {default}
     bool JVMCIPrintProperties                     = false                          {JVMCI experimental} {default}
     intx JVMCIThreads                             = 1                              {JVMCI experimental} {default}
     intx JVMCITraceLevel                          = 0                              {JVMCI experimental} {default}
     intx MethodProfileWidth                       = 0                              {JVMCI experimental} {default}
     intx MonitorUsedDeflationThreshold            = 90                                   {experimental} {default}
   double ObjectCountCutOffPercent                 = 0.500000                             {experimental} {default}
     intx PerMethodSpecTrapLimit                   = 5000                                 {experimental} {default}
     bool PostLoopMultiversioning                  = false                             {C2 experimental} {default}
     bool PrintAOT                                 = false                                {experimental} {default}
     bool PrintBootstrap                           = true                           {JVMCI experimental} {default}
   size_t ReferencesPerThread                      = 1000                                 {experimental} {default}
    uintx ShenandoahAllocSpikeFactor               = 5                                    {experimental} {default}
    uintx ShenandoahAllocationThreshold            = 0                                    {experimental} {default}
     bool ShenandoahAlwaysClearSoftRefs            = false                                {experimental} {default}
    uintx ShenandoahControlIntervalAdjustPeriod    = 1000                                 {experimental} {default}
    uintx ShenandoahControlIntervalMax             = 10                                   {experimental} {default}
    uintx ShenandoahControlIntervalMin             = 1                                    {experimental} {default}
    uintx ShenandoahCriticalFreeThreshold          = 1                                    {experimental} {default}
    uintx ShenandoahEvacReserve                    = 5                                    {experimental} {default}
     bool ShenandoahEvacReserveOverflow            = true                                 {experimental} {default}
   double ShenandoahEvacWaste                      = 1.200000                             {experimental} {default}
    uintx ShenandoahFullGCThreshold                = 3                                    {experimental} {default}
    uintx ShenandoahGarbageThreshold               = 25                                   {experimental} {default}
    uintx ShenandoahGuaranteedGCInterval           = 300000                               {experimental} {default}
     intx ShenandoahHumongousThreshold             = 100                                  {experimental} {default}
    uintx ShenandoahImmediateThreshold             = 90                                   {experimental} {default}
     bool ShenandoahImplicitGCInvokesConcurrent    = false                                {experimental} {default}
    uintx ShenandoahInitFreeThreshold              = 70                                   {experimental} {default}
    uintx ShenandoahLearningSteps                  = 5                                    {experimental} {default}
    uintx ShenandoahMarkLoopStride                 = 1000                                 {experimental} {default}
     intx ShenandoahMarkScanPrefetch               = 32                                   {experimental} {default}
   size_t ShenandoahMaxRegionSize                  = 33554432                             {experimental} {default}
    uintx ShenandoahMaxSATBBufferFlushes           = 5                                    {experimental} {default}
    uintx ShenandoahMinFreeThreshold               = 10                                   {experimental} {default}
   size_t ShenandoahMinRegionSize                  = 262144                               {experimental} {default}
     bool ShenandoahPacing                         = true                                 {experimental} {default}
    uintx ShenandoahPacingCycleSlack               = 10                                   {experimental} {default}
    uintx ShenandoahPacingIdleSlack                = 2                                    {experimental} {default}
    uintx ShenandoahPacingMaxDelay                 = 10                                   {experimental} {default}
   double ShenandoahPacingSurcharge                = 1.100000                             {experimental} {default}
    uintx ShenandoahParallelRegionStride           = 1024                                 {experimental} {default}
    uintx ShenandoahRefProcFrequency               = 5                                    {experimental} {default}
     bool ShenandoahRegionSampling                 = false                                {experimental} {default}
      int ShenandoahRegionSamplingRate             = 40                                   {experimental} {default}
   size_t ShenandoahRegionSize                     = 0                                    {experimental} {default}
   size_t ShenandoahSATBBufferSize                 = 1024                                 {experimental} {default}
     bool ShenandoahSuspendibleWorkers             = false                                {experimental} {default}
   size_t ShenandoahTargetNumRegions               = 2048                                 {experimental} {default}
     bool ShenandoahUncommit                       = true                                 {experimental} {default}
    uintx ShenandoahUncommitDelay                  = 300000                               {experimental} {default}
    uintx ShenandoahUnloadClassesFrequency         = 100                                  {experimental} {default}
     intx SpecTrapLimitExtraEntries                = 3                                    {experimental} {default}
     intx SurvivorAlignmentInBytes                 = 8                                    {experimental} {default}
    uintx SymbolTableSize                          = 20011                                {experimental} {default}
     intx SyncFlags                                = 0                                    {experimental} {default}
    ccstr SyncKnobs                                =                                      {experimental} {default}
     intx SyncVerbose                              = 0                                    {experimental} {default}
     bool TrustFinalNonStaticFields                = false                                {experimental} {default}
     bool UnlockExperimentalVMOptions              = true                                 {experimental} {command line}
     bool UseAOT                                   = false                                {experimental} {ergonomic}
     bool UseCriticalCMSThreadPriority             = false                                {experimental} {default}
     bool UseCriticalCompilerThreadPriority        = false                                {experimental} {default}
     bool UseCriticalJavaThreadPriority            = false                                {experimental} {default}
     bool UseEpsilonGC                             = false                                {experimental} {default}
     bool UseFastUnorderedTimeStamps               = false                                {experimental} {default}
     bool UseJVMCICompiler                         = false                          {JVMCI experimental} {default}
     bool UseZGC                                   = false                                {experimental} {default}
    uintx WorkStealingHardSpins                    = 4096                                 {experimental} {default}
    uintx WorkStealingSleepMillis                  = 1                                    {experimental} {default}
    uintx WorkStealingSpinToYieldRatio             = 10                                   {experimental} {default}
    uintx WorkStealingYieldsBeforeSleep            = 5000                                 {experimental} {default}
     intx hashCode                                 = 5                                    {experimental} {default}
openjdk version "11.0.17" 2022-10-18
OpenJDK Runtime Environment Temurin-11.0.17+8 (build 11.0.17+8)
OpenJDK 64-Bit Server VM Temurin-11.0.17+8 (build 11.0.17+8, mixed mode)