网站建设linux,做网站找公司怎么找,网络维护服务合同,沈阳网站建设开发维护目录 一、堆的核心概述二、堆的内存细分#xff08;按分代收集理论设计#xff09;2.1 java7及以前2.2 java8及以后 三、堆内存大小3.1 说明3.2 参数设置3.3 默认大小3.4 手动设置3.5 jps3.6 jstat3.7 OutOfMemory举例 四、年轻代与老年代4.1 说明 五、对象分配过程5.1 说明5… 目录 一、堆的核心概述二、堆的内存细分按分代收集理论设计2.1 java7及以前2.2 java8及以后 三、堆内存大小3.1 说明3.2 参数设置3.3 默认大小3.4 手动设置3.5 jps3.6 jstat3.7 OutOfMemory举例 四、年轻代与老年代4.1 说明 五、对象分配过程5.1 说明5.2 对象分配举个例子 六、堆空间分代思想七、内存分配策略八、对象分配内存:TLAB8.1 说明8.2 TLAB 九、堆空间参数设置9.1 说明9.2 示例代码9.3 查看所有的参数的默认初始值9.4 查看所有的参数的最终值9.5 查看某个参数的指令 十、截图示例10.1 new对象指令10.2 jdk7的gc信息10.3 jdk8的gc信息 一、堆的核心概述 1. 一个JVM实例只存在一个堆内存堆也是Java内存管理的核心区域 2. Java 堆区在JVM 启动的时候即被创建其空间大小也就确定了。是JVM管理的最大一块内存空间 3. 堆内存的大小是可以调节的 4. 《Java虚拟机规范》规定堆可以处于物理上不连续的内存空间中但在逻辑上它应该被视为连续的 5. 所有的线程共享Java堆在这里还可以划分线程私有的缓冲区 (ThreadLocal Allocation Buffer TLAB) 6.《Java虚拟机规范》中对Java堆的描述是所有的对象实例以及数组都应当在运行时分配在堆上 7. The heap is the run-time data area from which memory for all class instances and arrays is allocated 8. 从实际使用角度看“几乎”所有的对象实例都在这里分配内存 9. 数组和对象可能永远不会存储在栈上因为栈帧中保存引用这个引用指向对象或者数组在堆中的位置 10. 在方法结束后堆中的对象不会马上被移除仅仅在垃圾收集的时候才会被移除 11. 堆是GC ( Garbage collection垃圾收集器) 执行垃圾回收的重点区域
二、堆的内存细分按分代收集理论设计
2.1 java7及以前 1. 分为新生区、养老区、永久区 2. 新生区又叫新生代、年轻代Young Generation Space、Young/New 3. 新生区又被划分为Eden区和Survivor区 4. 养老区又叫老年区、老年代Tenure generation spaceOld/Tenure 5. 永久区又叫永久代Permanent SpacePerm
2.2 java8及以后 1. 分为新生区、养老区、元空间 2. 元空间Meta SpaceMeta
三、堆内存大小
3.1 说明 1. Java堆区用于存储Java对象实例堆的大小在JVM启动时就已经设定好了 2. 可以通过选项-Xmx和-Xms来进行设置 3. “-Xms”用于表示堆区的起始内存(memory start)等价于-XX:InitialHeapSize 4. “-Xmx”则用于表示堆区的最大内存(max)等价于-XX:MaxHeapSize 5. 一旦堆区中的内存大小超过“-Xmx”所指定的最大内存(max size)时将会抛出OutOfMemoryError异常 6. 通常会将 -Xms 和-Xmx两个参数配置相同的值目的是为了能够在java垃圾回收机制清理完堆区后不需要重新分隔计算堆区的大小从而提高性能。
3.2 参数设置 1. 设置堆空间大小的参数 2. -Xms 用来设置堆空间(新生代和老年代)的初始内存大小 3. -X 是jvm的运行参数 4. ms 是memory start 5. -Xmx 用来设置堆空间新生代和老年代的最大内存大小
3.3 默认大小 1. 初始内存大小物理电脑内存大小/64 2. 最大内存大小物理电脑内存大小/4
3.4 手动设置 1. -Xms600m -Xmx600m 2. 开发中建议将初始堆内存和最大的堆内存设置成相同的值
3.5 jps 1.查看java进程
3.6 jstat 1. 查看java进程的gc信息
// 11908是进程id
jstat -gc 119082. S0C是新生代的survivor0区内存总量大小 3. S1C是新生代的survivor1区内存总量大小 4. S0U是新生代的survivor0区已使用的内存总量大小 5. S1U是新生代的survivor1区已使用的内存总量大小 6. EC是新生代的eden区内存总量大小 7. EU是新生代的eden区已使用的内存总量大小 8. OC是老年代内存总量大小 9. OU是老年代内存使用的大小 10. S0C和S1C只有其中一个纳入计算用一个是因为gc的回收算法
3.7 OutOfMemory举例
package com.learning.heap.out_of_memory;import java.util.ArrayList;
import java.util.Random;/*** Author wangyouhui* Description oom测试**/
public class OutOfMemoryTest {public static void main(String[] args) {ArrayListPicture list new ArrayList();while(true){try {Thread.sleep(20);} catch (InterruptedException e) {e.printStackTrace();}list.add(new Picture(new Random().nextInt(1024*1024)));}}
}class Picture{private byte[] pixels;public Picture(int length){this.pixels new byte[length];}
} 四、年轻代与老年代
4.1 说明 1. 存储在JVM中的Java对象可以被划分为两类: 一类是生命周期较短的瞬时对象这类对象的创建和消亡都非常迅速。 2. 另外一类对象的生命周期却非常长在某些极端的情况下还能够与JVM的生命周期保持一致。 3. Java堆区进一步细分可以划分为年轻代(YoungGen)和老年代 (oldGen) 4. 其中年轻代又可以划分为Eden空间、Survivor0空间和Survivor1空间(有时也叫做 from区、to区) 5. 内存结构图如下 6. 新生代和老年代在堆结构的占比图 7. 默认-XX:NewRatio2表示新生代占1老年代占2新生代占整个堆的1/3 8. 修改-XX:NewRatio4表示新生代占1老年代占4新生代占整个堆的1/5 9. 在HotSpot中Eden空间和另外两个survivor空间缺省所占的比例是8:1:1但默认情况下并不是8:1:1有个自适应的内存比例如下图是6:1:1
package com.learning.heap;/*** Author wangyouhui* Description eden区域与幸存者区占比* -XX:NewRatio :设置新生代与老年代的比例。默认值是2* -XX:SurvivorRatio : 资置新生代中Eden区与Survivor区的比例* -XX:-UseAdaptivesizePolicy : 关闭自适应的内存分配策略**/
public class EdenSurvivorTest {public static void main(String[] args) {System.out.println(eden区域与幸存者区占比);try {Thread.sleep(10000000);} catch (InterruptedException e) {e.printStackTrace();}}
} 10. 当然开发人员可以通过选项“-XX:SurvivorRatio”调整这个空间比例。比如-XX:SurvivorRatio8 11. 几乎所有的Java对象都是在Eden区被new出来的。如果对象太大Eden区放不下会则在老年代中被new 12. 绝大部分的Java对象的销毁都在新生代进行了 13. IBM 公司的专门研究表明新生代中 80的对象都是“朝生夕死”的可以使用选项”-Xmn设置新生代最大内存大小 14. 这个参数一般使用默认值就可以·
五、对象分配过程
5.1 说明 1. 为新对象分配内存是一件非常严谨和复杂的任务JVM的设计者们不仅需要考虑内存如何分配、在哪里分配等问题并且由于内存分配算法与内存回收算法密切相关所以还需要考虑GC执行完内存回收后是否会在内存空间中产生内存碎片。 2. new的对象先放伊甸园区。此区有大小限制。 3. 当伊甸园的空间填满时程序又需要创建对象JVM的垃圾回收器将对伊甸园区进行垃圾回收(Minor GC)将伊甸园区中的不再被其他对象所引用的对象进行销毁。再加载新的对象放到伊甸园区 4. 然后将伊甸园中的剩余对象移动到幸存者0区。 5. 如果再次触发垃圾回收此时上次幸存下来的放到幸存者0区的如果没有回收就会放到幸存者1区。 6. 如果再次经历垃圾回收此时会重新放回幸存者0区接着再去幸存者1区 7. 可以设置次数来决定啥时候去养老区默认是15次。 8. 可以设置参数: -XX:MaxTenurinaThreshold进行设置 9. 在养老区相对悠闲。当养老区内存不足时再次触发GC: Major GC进行养老区的内存清理。 10. 若养老区执行了Major GC之后发现依然无法进行对象的保存就会产生OOM异常java.lang.OutofMemoryError: Java heap space 11. 针对幸存者s0,s1区的总结: 复制之后有交换谁空谁是To 12. 关于垃圾回收:频繁在新生区收集很少在养老区收集几乎不在永久区元空间收集。
5.2 对象分配举个例子 1. 准备new三个对象A、B、C、D 2. 如果D很大eden区放不下则直接把D放入养老区 3. A、B、C比较小分配在eden区 4. 分配对象在eden区eden区满了放不下了会触发年轻代的垃圾回收Young GC或者Minor GC 5. 触发Young GC后会Stop The World(STW)停止用户线程来判断可达性分析算法哪些是可以回收的垃圾对象 6. 经过Young GC发现C是垃圾没有任何引用指向不再使用A和B还有引用指向 7. 把A和B提升到幸存者区To区并且将A和B的年龄计数器加1即A和B的年龄为1此时To区变为From区另一个空的幸存者区变为To区 8. eden区再陆续放入对象E、F、G然后eden区又满了再次触发Young GC此时F、G是垃圾E则被放入幸存者To区E的年龄计数器加1即E的年龄为1 9. Young GC也会判断幸存者From区的A和B如果还在被占用不能被回收则把幸存者From区的A和B放入幸存者To区对应的年龄计数器加1即A和B的年龄为2如果能回收则回收了 10. 此时幸存者From区为空则变为幸存者To区原来的To区改为From区每次执行完Young GC谁是空谁就是幸存者To区 11. 上述过程不断累积当幸存者From区的A和B的年龄达到15再进行Young GC时则将A和B做一次晋升即晋升到老年代相应的年龄计数器加1即A和B的年龄为1615则被称为阈值 12. 当eden区满了才会触发Young GC幸存者区满了不会触发Young GC会将eden区和幸存者区一起回收当幸存者区满了会将其对象直接晋升为老年代
六、堆空间分代思想 1.不分代完全可以分代的唯一理由就是优化GC性能。 2.如果没有分代那所有的对象都在一块GC的时候要找到哪些对象没用这样就会对堆的所有区域进行扫描。 3.而很多对象都是朝生夕死的如果分代的话把新创建的对象放到某一地方当GC 的时候先把这块存储“朝生夕死”对象的区域进行回收这样就会腾出很大的空间出来。
七、内存分配策略 1.如果对象在Eden 出生并经过第一次MinorGC 后仍然存活并且能被Survivor容纳的话将被移动到Survivor 空间中 并将对象年龄设为1 。 2.对象在年龄就增加1 岁当它的年龄增加到一定Survivor 区中每熬过一次MinorGC 程度(默认为15 岁其实每个JVM、每个GC都有所不同) 时就会被晋升到老年代中。 3.对象晋升老年代的年龄闯值可以通过选项-XX:MaxTenuringThreshold来设置。 4.针对不同年龄段的对象分配原则优先分配到Eden大对象直接分配到老年代尽量避免程序中出现过多的大对象 5.长期存活的对象分配到老年代 6.动态对象年龄判断如果survivor 区中相同年龄的所有对象大小的总和大于survivor空间的一半年龄大于或等于该年龄的对象可以直接进入老年代无须等到MaxTenuringThreshold 中要求的年龄。 7.空间分配担保-XX:HandlePromotionFailure
八、对象分配内存:TLAB
8.1 说明 1.Thread Local Allocation Buffer 2.堆区是线程共享区域任何线程都可以访问到堆区中的共享数据 3.由于对象实例的创建在JVM中非常频繁因此在并发环境下从堆区中划分内存空间是线程不安全的 4.为避免多个线程操作同一地址需要使用加锁等机制进而影响分配速度 5.尽管不是所有的对象实例都能够在TLAB中成功分配内存但JVM确实是将TLAB作为内存分配的首选。 6.在程序中开发人员可以通过选项“-xx:UseTLAB”设置是否开启TLAB空间。默认是开启的 7.默认情况下TLAB空间的内存非常小仅占有整个Eden空间的1号当然我们可以通过选项“XX:TLABWasteTargetPercent”设置TLAB空间所占用Eden空间的百分比大小。 8.一旦对象在TLAB空间分配内存失败时JVM就会尝试着通过使用加锁机制确保数据操作的原子性从而直接在Eden空间中分配内存。
8.2 TLAB 1.从内存模型而不是垃圾收集的角度对Eden区域继续进行划分JVM为每个线程分配了一个私有缓存区域它包含在Eden空间内。 2.多线程同时分配内存时使用TLAB可以避免一系列的非线程安全问题同时还能够提升内存分配的吞吐量因此我们可以将这种内存分配方式称之为快速分配策略 3.几乎所有openJDK衍生出来的JVM都提供了TLAB的设计。
九、堆空间参数设置
9.1 说明 1.官网说明https://docs.oracle.com/javase/8/docs/technotes/tools/unix/java.html 2.-XX:PrintFlagsInitial查看所有的参数的默认初始值 3.-XX:PrintFlagsFinal查看所有的参数的最终值可能会存在修改不再是初值 4.-Xms:初始堆空间内存默认为物理内存的1/64 5.-Xmx:最大堆空间内存默认为物理内存的1/4 6.-Xmn:设置新生代的大小初始值及最大值 7.-XX:NewRatio配置新生代与老年代在堆结构的占比 8.-XX:SurvivorRatio: 设置新生代中Eden和SO/S1空间的比例 9.-XX:MaxTenuringThreshold: 设置新生代垃圾的最大年龄10.-XX:PrintGCDetails; 输出详细的GC处理日志:打印gc简要信息:-XX:PrintGC或-verbose:gc11.-XX:HandlePromotionFailure: 是否设置空间分配担保
9.2 示例代码
package com.learning.heap.args;/*** Author wangyouhui* Description 堆参数测试* -XX:PrintFlagsInitial 查看所有的参数的默认初始值* -XX:PrintFlagsFinal 查看所有的参数的最终值可能会存在修改不再是初始值* -Xms 初始堆空间内存默认为物理内存的1/64* -Xmx 最大堆空间内存默认为物理内存的1/4* -Xmn 设置新生代的大小初始值及最大值* -XX:NewRatio 配置新生代与老年代在堆结构的占比* -XX:SurvivorRatio 设置新生代中Eden和S0/S1空间的比例* -XX:MaxTenuringThreashold 设置新生代垃圾的最大年龄* -XX:PrintGCDetails 输出详细的GC处理日志* -XX:PrintGC 打印gc简要信息* -verbose:gc 打印gc简要信息* -XX:HandlePromotionFailure 是否设置空间分配担保**/
public class HeapArgsTest {public static void main(String[] args) {System.out.println(hello world);}
}
9.3 查看所有的参数的默认初始值 [Global flags]intx ActiveProcessorCount -1 {product}uintx AdaptiveSizeDecrementScaleFactor 4 {product}uintx AdaptiveSizeMajorGCDecayTimeScale 10 {product}uintx AdaptiveSizePausePolicy 0 {product}uintx AdaptiveSizePolicyCollectionCostMargin 50 {product}uintx AdaptiveSizePolicyInitializingSteps 20 {product}uintx AdaptiveSizePolicyOutputInterval 0 {product}uintx AdaptiveSizePolicyWeight 10 {product}uintx AdaptiveSizeThroughPutPolicy 0 {product}uintx AdaptiveTimeWeight 25 {product}bool AdjustConcurrency false {product}bool AggressiveHeap false {product}bool AggressiveOpts false {product}intx AliasLevel 3 {C2 product}bool AlignVector true {C2 product}intx AllocateInstancePrefetchLines 1 {product}intx AllocatePrefetchDistance -1 {product}intx AllocatePrefetchInstr 0 {product}intx AllocatePrefetchLines 3 {product}intx AllocatePrefetchStepSize 16 {product}intx AllocatePrefetchStyle 1 {product}bool AllowJNIEnvProxy false {product}bool AllowNonVirtualCalls false {product}bool AllowParallelDefineClass false {product}bool AllowUserSignalHandlers false {product}bool AlwaysActAsServerClassMachine false {product}bool AlwaysCompileLoopMethods false {product}bool AlwaysLockClassLoader false {product}bool AlwaysPreTouch false {product}bool AlwaysRestoreFPU false {product}bool AlwaysTenure false {product}bool AssertOnSuspendWaitFailure false {product}bool AssumeMP false {product}intx AutoBoxCacheMax 128 {C2 product}uintx AutoGCSelectPauseMillis 5000 {product}intx BCEATraceLevel 0 {product}intx BackEdgeThreshold 100000 {pd product}bool BackgroundCompilation true {pd product}uintx BaseFootPrintEstimate 268435456 {product}intx BiasedLockingBulkRebiasThreshold 20 {product}intx BiasedLockingBulkRevokeThreshold 40 {product}intx BiasedLockingDecayTime 25000 {product}intx BiasedLockingStartupDelay 4000 {product}bool BindGCTaskThreadsToCPUs false {product}bool BlockLayoutByFrequency true {C2 product}intx BlockLayoutMinDiamondPercentage 20 {C2 product}bool BlockLayoutRotateLoops true {C2 product}bool BranchOnRegister false {C2 product}bool BytecodeVerificationLocal false {product}bool BytecodeVerificationRemote true {product}bool C1OptimizeVirtualCallProfiling true {C1 product}bool C1ProfileBranches true {C1 product}bool C1ProfileCalls true {C1 product}bool C1ProfileCheckcasts true {C1 product}bool C1ProfileInlinedCalls true {C1 product}bool C1ProfileVirtualCalls true {C1 product}bool C1UpdateMethodData true {C1 product}intx CICompilerCount 2 {product}bool CICompilerCountPerCPU false {product}bool CITime false {product}bool CMSAbortSemantics false {product}uintx CMSAbortablePrecleanMinWorkPerIteration 100 {product}intx CMSAbortablePrecleanWaitMillis 100 {manageable}uintx CMSBitMapYieldQuantum 10485760 {product}uintx CMSBootstrapOccupancy 50 {product}bool CMSClassUnloadingEnabled true {product}uintx CMSClassUnloadingMaxInterval 0 {product}bool CMSCleanOnEnter true {product}bool CMSCompactWhenClearAllSoftRefs true {product}uintx CMSConcMarkMultiple 32 {product}bool CMSConcurrentMTEnabled true {product}uintx CMSCoordinatorYieldSleepCount 10 {product}bool CMSDumpAtPromotionFailure false {product}bool CMSEdenChunksRecordAlways true {product}uintx CMSExpAvgFactor 50 {product}bool CMSExtrapolateSweep false {product}uintx CMSFullGCsBeforeCompaction 0 {product}uintx CMSIncrementalDutyCycle 10 {product}uintx CMSIncrementalDutyCycleMin 0 {product}bool CMSIncrementalMode false {product}uintx CMSIncrementalOffset 0 {product}bool CMSIncrementalPacing true {product}uintx CMSIncrementalSafetyFactor 10 {product}uintx CMSIndexedFreeListReplenish 4 {product}intx CMSInitiatingOccupancyFraction -1 {product}uintx CMSIsTooFullPercentage 98 {product}double CMSLargeCoalSurplusPercent 0.950000 {product}double CMSLargeSplitSurplusPercent 1.000000 {product}bool CMSLoopWarn false {product}uintx CMSMaxAbortablePrecleanLoops 0 {product}intx CMSMaxAbortablePrecleanTime 5000 {product}uintx CMSOldPLABMax 1024 {product}uintx CMSOldPLABMin 16 {product}uintx CMSOldPLABNumRefills 4 {product}uintx CMSOldPLABReactivityFactor 2 {product}bool CMSOldPLABResizeQuicker false {product}uintx CMSOldPLABToleranceFactor 4 {product}bool CMSPLABRecordAlways true {product}uintx CMSParPromoteBlocksToClaim 16 {product}bool CMSParallelInitialMarkEnabled true {product}bool CMSParallelRemarkEnabled true {product}bool CMSParallelSurvivorRemarkEnabled true {product}uintx CMSPrecleanDenominator 3 {product}uintx CMSPrecleanIter 3 {product}uintx CMSPrecleanNumerator 2 {product}bool CMSPrecleanRefLists1 true {product}bool CMSPrecleanRefLists2 false {product}bool CMSPrecleanSurvivors1 false {product}bool CMSPrecleanSurvivors2 true {product}uintx CMSPrecleanThreshold 1000 {product}bool CMSPrecleaningEnabled true {product}bool CMSPrintChunksInDump false {product}bool CMSPrintEdenSurvivorChunks false {product}bool CMSPrintObjectsInDump false {product}uintx CMSRemarkVerifyVariant 1 {product}bool CMSReplenishIntermediate true {product}uintx CMSRescanMultiple 32 {product}uintx CMSSamplingGrain 16384 {product}bool CMSScavengeBeforeRemark false {product}uintx CMSScheduleRemarkEdenPenetration 50 {product}uintx CMSScheduleRemarkEdenSizeThreshold 2097152 {product}uintx CMSScheduleRemarkSamplingRatio 5 {product}double CMSSmallCoalSurplusPercent 1.050000 {product}double CMSSmallSplitSurplusPercent 1.100000 {product}bool CMSSplitIndexedFreeListBlocks true {product}intx CMSTriggerInterval -1 {manageable}uintx CMSTriggerRatio 80 {product}intx CMSWaitDuration 2000 {manageable}uintx CMSWorkQueueDrainThreshold 10 {product}bool CMSYield true {product}uintx CMSYieldSleepCount 0 {product}uintx CMSYoungGenPerWorker 67108864 {pd product}uintx CMS_FLSPadding 1 {product}uintx CMS_FLSWeight 75 {product}uintx CMS_SweepPadding 1 {product}uintx CMS_SweepTimerThresholdMillis 10 {product}uintx CMS_SweepWeight 75 {product}bool CheckEndorsedAndExtDirs false {product}bool CheckJNICalls false {product}bool ClassUnloading true {product}bool ClassUnloadingWithConcurrentMark true {product}intx ClearFPUAtPark 0 {product}bool ClipInlining true {product}uintx CodeCacheExpansionSize 65536 {pd product}uintx CodeCacheMinimumFreeSpace 512000 {product}bool CollectGen0First false {product}bool CompactFields true {product}intx CompilationPolicyChoice 0 {product}
ccstrlist CompileCommand {product}ccstr CompileCommandFile {product}
ccstrlist CompileOnly {product}intx CompileThreshold 10000 {pd product}bool CompilerThreadHintNoPreempt true {product}intx CompilerThreadPriority -1 {product}intx CompilerThreadStackSize 0 {pd product}uintx CompressedClassSpaceSize 1073741824 {product}uintx ConcGCThreads 0 {product}intx ConditionalMoveLimit 3 {C2 pd product}intx ContendedPaddingWidth 128 {product}bool ConvertSleepToYield true {pd product}bool ConvertYieldToSleep false {product}bool CrashOnOutOfMemoryError false {product}bool CreateMinidumpOnCrash false {product}bool CriticalJNINatives true {product}bool DTraceAllocProbes false {product}bool DTraceMethodProbes false {product}bool DTraceMonitorProbes false {product}bool Debugging false {product}uintx DefaultMaxRAMFraction 4 {product}intx DefaultThreadPriority -1 {product}intx DeferPollingPageLoopCount -1 {product}intx DeferThrSuspendLoopCount 4000 {product}bool DeoptimizeRandom false {product}bool DisableAttachMechanism false {product}bool DisableExplicitGC false {product}bool DisplayVMOutputToStderr false {product}bool DisplayVMOutputToStdout false {product}bool DoEscapeAnalysis true {C2 product}bool DontCompileHugeMethods true {product}bool DontYieldALot false {pd product}ccstr DumpLoadedClassList {product}bool DumpReplayDataOnError true {product}bool DumpSharedSpaces false {product}bool EagerXrunInit false {product}intx EliminateAllocationArraySizeLimit 64 {C2 product}bool EliminateAllocations true {C2 product}bool EliminateAutoBox true {C2 product}bool EliminateLocks true {C2 product}bool EliminateNestedLocks true {C2 product}intx EmitSync 0 {product}bool EnableContended true {product}bool EnableResourceManagementTLABCache true {product}bool EnableSharedLookupCache true {product}bool EnableTracing false {product}uintx ErgoHeapSizeLimit 0 {product}ccstr ErrorFile {product}ccstr ErrorReportServer {product}double EscapeAnalysisTimeout 20.000000 {C2 product}bool EstimateArgEscape true {product}bool ExitOnOutOfMemoryError false {product}bool ExplicitGCInvokesConcurrent false {product}bool ExplicitGCInvokesConcurrentAndUnloadsClasses false {product}bool ExtendedDTraceProbes false {product}ccstr ExtraSharedClassListFile {product}bool FLSAlwaysCoalesceLarge false {product}uintx FLSCoalescePolicy 2 {product}double FLSLargestBlockCoalesceProximity 0.990000 {product}bool FailOverToOldVerifier true {product}bool FastTLABRefill true {product}intx FenceInstruction 0 {ARCH product}intx FieldsAllocationStyle 1 {product}bool FilterSpuriousWakeups true {product}ccstr FlightRecorderOptions {product}bool ForceNUMA false {product}bool ForceTimeHighResolution false {product}intx FreqInlineSize 325 {pd product}double G1ConcMarkStepDurationMillis 10.000000 {product}uintx G1ConcRSHotCardLimit 4 {product}uintx G1ConcRSLogCacheSize 10 {product}intx G1ConcRefinementGreenZone 0 {product}intx G1ConcRefinementRedZone 0 {product}intx G1ConcRefinementServiceIntervalMillis 300 {product}uintx G1ConcRefinementThreads 0 {product}intx G1ConcRefinementThresholdStep 0 {product}intx G1ConcRefinementYellowZone 0 {product}uintx G1ConfidencePercent 50 {product}uintx G1HeapRegionSize 0 {product}uintx G1HeapWastePercent 5 {product}uintx G1MixedGCCountTarget 8 {product}intx G1RSetRegionEntries 0 {product}uintx G1RSetScanBlockSize 64 {product}intx G1RSetSparseRegionEntries 0 {product}intx G1RSetUpdatingPauseTimePercent 10 {product}intx G1RefProcDrainInterval 10 {product}uintx G1ReservePercent 10 {product}uintx G1SATBBufferEnqueueingThresholdPercent 60 {product}intx G1SATBBufferSize 1024 {product}intx G1UpdateBufferSize 256 {product}bool G1UseAdaptiveConcRefinement true {product}uintx GCDrainStackTargetSize 64 {product}uintx GCHeapFreeLimit 2 {product}uintx GCLockerEdenExpansionPercent 5 {product}bool GCLockerInvokesConcurrent false {product}uintx GCLogFileSize 8192 {product}uintx GCPauseIntervalMillis 0 {product}uintx GCTaskTimeStampEntries 200 {product}uintx GCTimeLimit 98 {product}uintx GCTimeRatio 99 {product}uintx HeapBaseMinAddress 2147483648 {pd product}bool HeapDumpAfterFullGC false {manageable}bool HeapDumpBeforeFullGC false {manageable}bool HeapDumpOnOutOfMemoryError false {manageable}ccstr HeapDumpPath {manageable}uintx HeapFirstMaximumCompactionCount 3 {product}uintx HeapMaximumCompactionInterval 20 {product}uintx HeapSizePerGCThread 87241520 {product}bool IgnoreEmptyClassPaths false {product}bool IgnoreUnrecognizedVMOptions false {product}uintx IncreaseFirstTierCompileThresholdAt 50 {product}bool IncrementalInline true {C2 product}uintx InitialBootClassLoaderMetaspaceSize 4194304 {product}uintx InitialCodeCacheSize 2555904 {pd product}uintx InitialHeapSize 0 {product}uintx InitialRAMFraction 64 {product}double InitialRAMPercentage 1.562500 {product}uintx InitialSurvivorRatio 8 {product}uintx InitialTenuringThreshold 7 {product}uintx InitiatingHeapOccupancyPercent 45 {product}bool Inline true {product}ccstr InlineDataFile {product}intx InlineSmallCode 1000 {pd product}bool InlineSynchronizedMethods true {C1 product}bool InsertMemBarAfterArraycopy true {C2 product}intx InteriorEntryAlignment 16 {C2 pd product}intx InterpreterProfilePercentage 33 {product}bool JNIDetachReleasesMonitors true {product}bool JavaMonitorsInStackTrace true {product}intx JavaPriority10_To_OSPriority -1 {product}intx JavaPriority1_To_OSPriority -1 {product}intx JavaPriority2_To_OSPriority -1 {product}intx JavaPriority3_To_OSPriority -1 {product}intx JavaPriority4_To_OSPriority -1 {product}intx JavaPriority5_To_OSPriority -1 {product}intx JavaPriority6_To_OSPriority -1 {product}intx JavaPriority7_To_OSPriority -1 {product}intx JavaPriority8_To_OSPriority -1 {product}intx JavaPriority9_To_OSPriority -1 {product}bool LIRFillDelaySlots false {C1 pd product}uintx LargePageHeapSizeThreshold 134217728 {product}uintx LargePageSizeInBytes 0 {product}bool LazyBootClassLoader true {product}intx LiveNodeCountInliningCutoff 40000 {C2 product}bool LogCommercialFeatures false {product}intx LoopMaxUnroll 16 {C2 product}intx LoopOptsCount 43 {C2 product}intx LoopUnrollLimit 60 {C2 pd product}intx LoopUnrollMin 4 {C2 product}bool LoopUnswitching true {C2 product}bool ManagementServer false {product}uintx MarkStackSize 4194304 {product}uintx MarkStackSizeMax 536870912 {product}uintx MarkSweepAlwaysCompactCount 4 {product}uintx MarkSweepDeadRatio 5 {product}intx MaxBCEAEstimateLevel 5 {product}intx MaxBCEAEstimateSize 150 {product}uintx MaxDirectMemorySize 0 {product}bool MaxFDLimit true {product}uintx MaxGCMinorPauseMillis 4294967295 {product}uintx MaxGCPauseMillis 4294967295 {product}uintx MaxHeapFreeRatio 70 {manageable}uintx MaxHeapSize 130862280 {product}intx MaxInlineLevel 9 {product}intx MaxInlineSize 35 {product}intx MaxJNILocalCapacity 65536 {product}intx MaxJavaStackTraceDepth 1024 {product}intx MaxJumpTableSize 65000 {C2 product}intx MaxJumpTableSparseness 5 {C2 product}intx MaxLabelRootDepth 1100 {C2 product}intx MaxLoopPad 15 {C2 product}uintx MaxMetaspaceExpansion 5452592 {product}uintx MaxMetaspaceFreeRatio 70 {product}uintx MaxMetaspaceSize 4294967295 {product}uintx MaxNewSize 4294967295 {product}intx MaxNodeLimit 80000 {C2 product}uint64_t MaxRAM 0 {pd product}uintx MaxRAMFraction 4 {product}double MaxRAMPercentage 25.000000 {product}intx MaxRecursiveInlineLevel 1 {product}uintx MaxTenuringThreshold 15 {product}intx MaxTrivialSize 6 {product}intx MaxVectorSize 32 {C2 product}uintx MetaspaceSize 21810376 {pd product}bool MethodFlushing true {product}uintx MinHeapDeltaBytes 170392 {product}uintx MinHeapFreeRatio 40 {manageable}intx MinInliningThreshold 250 {product}intx MinJumpTableSize 10 {C2 pd product}uintx MinMetaspaceExpansion 340784 {product}uintx MinMetaspaceFreeRatio 40 {product}uintx MinRAMFraction 2 {product}double MinRAMPercentage 50.000000 {product}uintx MinSurvivorRatio 3 {product}uintx MinTLABSize 2048 {product}intx MonitorBound 0 {product}bool MonitorInUseLists false {product}intx MultiArrayExpandLimit 6 {C2 product}bool MustCallLoadClassInternal false {product}uintx NUMAChunkResizeWeight 20 {product}uintx NUMAInterleaveGranularity 2097152 {product}uintx NUMAPageScanRate 256 {product}uintx NUMASpaceResizeRate 1073741824 {product}bool NUMAStats false {product}ccstr NativeMemoryTracking off {product}bool NeedsDeoptSuspend false {pd product}bool NeverActAsServerClassMachine false {pd product}bool NeverTenure false {product}uintx NewRatio 2 {product}uintx NewSize 1363144 {product}uintx NewSizeThreadIncrease 5320 {pd product}intx NmethodSweepActivity 10 {product}intx NmethodSweepCheckInterval 5 {product}intx NmethodSweepFraction 16 {product}intx NodeLimitFudgeFactor 2000 {C2 product}uintx NumberOfGCLogFiles 0 {product}intx NumberOfLoopInstrToAlign 4 {C2 product}intx ObjectAlignmentInBytes 8 {lp64_product}uintx OldPLABSize 1024 {product}uintx OldPLABWeight 50 {product}uintx OldSize 5452592 {product}bool OmitStackTraceInFastThrow true {product}
ccstrlist OnError {product}
ccstrlist OnOutOfMemoryError {product}intx OnStackReplacePercentage 140 {pd product}bool OptimizeFill true {C2 product}bool OptimizePtrCompare true {C2 product}bool OptimizeStringConcat true {C2 product}bool OptoBundling false {C2 pd product}intx OptoLoopAlignment 16 {pd product}bool OptoScheduling false {C2 pd product}uintx PLABWeight 75 {product}bool PSChunkLargeArrays true {product}intx ParGCArrayScanChunk 50 {product}uintx ParGCDesiredObjsFromOverflowList 20 {product}bool ParGCTrimOverflow true {product}bool ParGCUseLocalOverflow false {product}uintx ParallelGCBufferWastePct 10 {product}uintx ParallelGCThreads 0 {product}bool ParallelGCVerbose false {product}uintx ParallelOldDeadWoodLimiterMean 50 {product}uintx ParallelOldDeadWoodLimiterStdDev 80 {product}bool ParallelRefProcBalancingEnabled true {product}bool ParallelRefProcEnabled false {product}bool PartialPeelAtUnsignedTests true {C2 product}bool PartialPeelLoop true {C2 product}intx PartialPeelNewPhiDelta 0 {C2 product}uintx PausePadding 1 {product}intx PerBytecodeRecompilationCutoff 200 {product}intx PerBytecodeTrapLimit 4 {product}intx PerMethodRecompilationCutoff 400 {product}intx PerMethodTrapLimit 100 {product}bool PerfAllowAtExitRegistration false {product}bool PerfBypassFileSystemCheck false {product}intx PerfDataMemorySize 32768 {product}intx PerfDataSamplingInterval 50 {product}ccstr PerfDataSaveFile {product}bool PerfDataSaveToFile false {product}bool PerfDisableSharedMem false {product}intx PerfMaxStringConstLength 1024 {product}intx PreInflateSpin 10 {pd product}bool PreferInterpreterNativeStubs false {pd product}intx PrefetchCopyIntervalInBytes -1 {product}intx PrefetchFieldsAhead -1 {product}intx PrefetchScanIntervalInBytes -1 {product}bool PreserveAllAnnotations false {product}bool PreserveFramePointer false {pd product}uintx PretenureSizeThreshold 0 {product}bool PrintAdaptiveSizePolicy false {product}bool PrintCMSInitiationStatistics false {product}intx PrintCMSStatistics 0 {product}bool PrintClassHistogram false {manageable}bool PrintClassHistogramAfterFullGC false {manageable}bool PrintClassHistogramBeforeFullGC false {manageable}bool PrintCodeCache false {product}bool PrintCodeCacheOnCompilation false {product}bool PrintCommandLineFlags false {product}bool PrintCompilation false {product}bool PrintConcurrentLocks false {manageable}intx PrintFLSCensus 0 {product}intx PrintFLSStatistics 0 {product}bool PrintFlagsFinal false {product}bool PrintFlagsInitial false {product}bool PrintGC false {manageable}bool PrintGCApplicationConcurrentTime false {product}bool PrintGCApplicationStoppedTime false {product}bool PrintGCCause true {product}bool PrintGCDateStamps false {manageable}bool PrintGCDetails false {manageable}bool PrintGCID false {manageable}bool PrintGCTaskTimeStamps false {product}bool PrintGCTimeStamps false {manageable}bool PrintHeapAtGC false {product rw}bool PrintHeapAtGCExtended false {product rw}bool PrintHeapAtSIGBREAK true {product}bool PrintJNIGCStalls false {product}bool PrintJNIResolving false {product}bool PrintOldPLAB false {product}bool PrintOopAddress false {product}bool PrintPLAB false {product}bool PrintParallelOldGCPhaseTimes false {product}bool PrintPromotionFailure false {product}bool PrintReferenceGC false {product}bool PrintSafepointStatistics false {product}intx PrintSafepointStatisticsCount 300 {product}intx PrintSafepointStatisticsTimeout -1 {product}bool PrintSharedArchiveAndExit false {product}bool PrintSharedDictionary false {product}bool PrintSharedSpaces false {product}bool PrintStringDeduplicationStatistics false {product}bool PrintStringTableStatistics false {product}bool PrintTLAB false {product}bool PrintTenuringDistribution false {product}bool PrintTieredEvents false {product}bool PrintVMOptions false {product}bool PrintVMQWaitTime false {product}bool PrintWarnings true {product}uintx ProcessDistributionStride 4 {product}bool ProfileInterpreter true {pd product}bool ProfileIntervals false {product}intx ProfileIntervalsTicks 100 {product}intx ProfileMaturityPercentage 20 {product}bool ProfileVM false {product}bool ProfilerPrintByteCodeStatistics false {product}bool ProfilerRecordPC false {product}uintx PromotedPadding 3 {product}uintx QueuedAllocationWarningCount 0 {product}uintx RTMRetryCount 5 {ARCH product}bool RangeCheckElimination true {product}intx ReadPrefetchInstr 0 {ARCH product}bool ReassociateInvariants true {C2 product}bool ReduceBulkZeroing true {C2 product}bool ReduceFieldZeroing true {C2 product}bool ReduceInitialCardMarks true {C2 product}bool ReduceSignalUsage false {product}intx RefDiscoveryPolicy 0 {product}bool ReflectionWrapResolutionErrors true {product}bool RegisterFinalizersAtInit true {product}bool RelaxAccessControlCheck false {product}ccstr ReplayDataFile {product}bool RequireSharedSpaces false {product}uintx ReservedCodeCacheSize 50331648 {pd product}bool ResizeOldPLAB true {product}bool ResizePLAB true {product}bool ResizeTLAB true {pd product}bool RestoreMXCSROnJNICalls false {product}bool RestrictContended true {product}bool RewriteBytecodes true {pd product}bool RewriteFrequentPairs true {pd product}intx SafepointPollOffset 256 {C1 pd product}intx SafepointSpinBeforeYield 2000 {product}bool SafepointTimeout false {product}intx SafepointTimeoutDelay 10000 {product}bool ScavengeBeforeFullGC true {product}intx SelfDestructTimer 0 {product}uintx SharedBaseAddress 0 {product}ccstr SharedClassListFile {product}uintx SharedMiscCodeSize 122880 {product}uintx SharedMiscDataSize 4194304 {product}uintx SharedReadOnlySize 16777216 {product}uintx SharedReadWriteSize 16777216 {product}bool ShowMessageBoxOnError false {product}intx SoftRefLRUPolicyMSPerMB 1000 {product}bool SpecialEncodeISOArray true {C2 product}bool SplitIfBlocks true {C2 product}intx StackRedPages 1 {pd product}intx StackShadowPages 6 {pd product}bool StackTraceInThrowable true {product}intx StackYellowPages 3 {pd product}bool StartAttachListener false {product}intx StarvationMonitorInterval 200 {product}bool StressLdcRewrite false {product}uintx StringDeduplicationAgeThreshold 3 {product}uintx StringTableSize 60013 {product}bool SuppressFatalErrorMessage false {product}uintx SurvivorPadding 3 {product}uintx SurvivorRatio 8 {product}intx SuspendRetryCount 50 {product}intx SuspendRetryDelay 5 {product}intx SyncFlags 0 {product}ccstr SyncKnobs {product}intx SyncVerbose 0 {product}uintx TLABAllocationWeight 35 {product}uintx TLABRefillWasteFraction 64 {product}uintx TLABSize 0 {product}bool TLABStats true {product}uintx TLABWasteIncrement 4 {product}uintx TLABWasteTargetPercent 1 {product}uintx TargetPLABWastePct 10 {product}uintx TargetSurvivorRatio 50 {product}uintx TenuredGenerationSizeIncrement 20 {product}uintx TenuredGenerationSizeSupplement 80 {product}uintx TenuredGenerationSizeSupplementDecay 2 {product}intx ThreadPriorityPolicy 0 {product}bool ThreadPriorityVerbose false {product}uintx ThreadSafetyMargin 52428800 {product}intx ThreadStackSize 0 {pd product}uintx ThresholdTolerance 10 {product}intx Tier0BackedgeNotifyFreqLog 10 {product}intx Tier0InvokeNotifyFreqLog 7 {product}intx Tier0ProfilingStartPercentage 200 {product}intx Tier23InlineeNotifyFreqLog 20 {product}intx Tier2BackEdgeThreshold 0 {product}intx Tier2BackedgeNotifyFreqLog 14 {product}intx Tier2CompileThreshold 0 {product}intx Tier2InvokeNotifyFreqLog 11 {product}intx Tier3BackEdgeThreshold 60000 {product}intx Tier3BackedgeNotifyFreqLog 13 {product}intx Tier3CompileThreshold 2000 {product}intx Tier3DelayOff 2 {product}intx Tier3DelayOn 5 {product}intx Tier3InvocationThreshold 200 {product}intx Tier3InvokeNotifyFreqLog 10 {product}intx Tier3LoadFeedback 5 {product}intx Tier3MinInvocationThreshold 100 {product}intx Tier4BackEdgeThreshold 40000 {product}intx Tier4CompileThreshold 15000 {product}intx Tier4InvocationThreshold 5000 {product}intx Tier4LoadFeedback 3 {product}intx Tier4MinInvocationThreshold 600 {product}bool TieredCompilation true {pd product}intx TieredCompileTaskTimeout 50 {product}intx TieredRateUpdateMaxTime 25 {product}intx TieredRateUpdateMinTime 1 {product}intx TieredStopAtLevel 4 {product}bool TimeLinearScan false {C1 product}bool TraceBiasedLocking false {product}bool TraceClassLoading false {product rw}bool TraceClassLoadingPreorder false {product}bool TraceClassPaths false {product}bool TraceClassResolution false {product}bool TraceClassUnloading false {product rw}bool TraceDynamicGCThreads false {product}bool TraceGen0Time false {product}bool TraceGen1Time false {product}ccstr TraceJVMTI {product}bool TraceLoaderConstraints false {product rw}bool TraceMetadataHumongousAllocation false {product}bool TraceMonitorInflation false {product}bool TraceParallelOldGCTasks false {product}intx TraceRedefineClasses 0 {product}bool TraceSafepointCleanupTime false {product}bool TraceSharedLookupCache false {product}bool TraceSuspendWaitFailures false {product}intx TrackedInitializationLimit 50 {C2 product}bool TransmitErrorReport false {product}bool TrapBasedNullChecks false {pd product}bool TrapBasedRangeChecks false {C2 pd product}intx TypeProfileArgsLimit 2 {product}uintx TypeProfileLevel 111 {pd product}intx TypeProfileMajorReceiverPercent 90 {C2 product}intx TypeProfileParmsLimit 2 {product}intx TypeProfileWidth 2 {product}intx UnguardOnExecutionViolation 0 {product}bool UnlinkSymbolsALot false {product}bool Use486InstrsOnly false {ARCH product}bool UseAES false {product}bool UseAESCTRIntrinsics false {product}bool UseAESIntrinsics false {product}intx UseAVX 99 {ARCH product}bool UseAdaptiveGCBoundary false {product}bool UseAdaptiveGenerationSizePolicyAtMajorCollection true {product}bool UseAdaptiveGenerationSizePolicyAtMinorCollection true {product}bool UseAdaptiveNUMAChunkSizing true {product}bool UseAdaptiveSizeDecayMajorGCCost true {product}bool UseAdaptiveSizePolicy true {product}bool UseAdaptiveSizePolicyFootprintGoal true {product}bool UseAdaptiveSizePolicyWithSystemGC false {product}bool UseAddressNop false {ARCH product}bool UseAltSigs false {product}bool UseAutoGCSelectPolicy false {product}bool UseBMI1Instructions false {ARCH product}bool UseBMI2Instructions false {ARCH product}bool UseBiasedLocking true {product}bool UseBimorphicInlining true {C2 product}bool UseBoundThreads true {product}bool UseCLMUL false {ARCH product}bool UseCMSBestFit true {product}bool UseCMSCollectionPassing true {product}bool UseCMSCompactAtFullCollection true {product}bool UseCMSInitiatingOccupancyOnly false {product}bool UseCRC32Intrinsics false {product}bool UseCodeCacheFlushing true {product}bool UseCompiler true {product}bool UseCompilerSafepoints true {product}bool UseCompressedClassPointers false {lp64_product}bool UseCompressedOops false {lp64_product}bool UseConcMarkSweepGC false {product}bool UseCondCardMark false {C2 product}bool UseCountLeadingZerosInstruction false {ARCH product}bool UseCountTrailingZerosInstruction false {ARCH product}bool UseCountedLoopSafepoints false {C2 product}bool UseCounterDecay true {product}bool UseDivMod true {C2 product}bool UseDynamicNumberOfGCThreads false {product}bool UseFPUForSpilling false {C2 product}bool UseFastAccessorMethods true {product}bool UseFastEmptyMethods true {product}bool UseFastJNIAccessors true {product}bool UseFastStosb false {ARCH product}bool UseG1GC false {product}bool UseGCLogFileRotation false {product}bool UseGCOverheadLimit true {product}bool UseGCTaskAffinity false {product}bool UseGHASHIntrinsics false {product}bool UseHeavyMonitors false {product}bool UseInlineCaches true {product}bool UseInterpreter true {product}bool UseJumpTables true {C2 product}bool UseLWPSynchronization true {product}bool UseLargePages false {pd product}bool UseLargePagesInMetaspace false {product}bool UseLargePagesIndividualAllocation : false {pd product}bool UseLockedTracing false {product}bool UseLoopCounter true {product}bool UseLoopInvariantCodeMotion true {C1 product}bool UseLoopPredicate true {C2 product}bool UseMathExactIntrinsics true {C2 product}bool UseMaximumCompactionOnSystemGC true {product}bool UseMembar false {pd product}bool UseMontgomeryMultiplyIntrinsic false {C2 product}bool UseMontgomerySquareIntrinsic false {C2 product}bool UseMulAddIntrinsic false {C2 product}bool UseMultiplyToLenIntrinsic false {C2 product}bool UseNUMA false {product}bool UseNUMAInterleaving false {product}bool UseNewLongLShift false {ARCH product}bool UseOSErrorReporting false {pd product}bool UseOldInlining true {C2 product}bool UseOnStackReplacement true {pd product}bool UseOnlyInlinedBimorphic true {C2 product}bool UseOptoBiasInlining true {C2 product}bool UsePSAdaptiveSurvivorSizePolicy true {product}bool UseParNewGC false {product}bool UseParallelGC false {product}bool UseParallelOldGC false {product}bool UsePerfData true {product}bool UsePopCountInstruction false {product}bool UseRDPCForConstantTableBase false {C2 product}bool UseRTMDeopt false {ARCH product}bool UseRTMLocking false {ARCH product}bool UseSHA false {product}bool UseSHA1Intrinsics false {product}bool UseSHA256Intrinsics false {product}bool UseSHA512Intrinsics false {product}intx UseSSE 99 {product}bool UseSSE42Intrinsics false {product}bool UseSerialGC false {product}bool UseSharedSpaces true {product}bool UseSignalChaining true {product}bool UseSquareToLenIntrinsic false {C2 product}bool UseStoreImmI16 true {ARCH product}bool UseStringDeduplication false {product}bool UseSuperWord true {C2 product}bool UseTLAB true {pd product}bool UseThreadPriorities true {pd product}bool UseTypeProfile true {product}bool UseTypeSpeculation true {C2 product}bool UseUTCFileTimestamp true {product}bool UseUnalignedLoadStores false {ARCH product}bool UseVMInterruptibleIO false {product}bool UseXMMForArrayCopy false {product}bool UseXmmI2D false {ARCH product}bool UseXmmI2F false {ARCH product}bool UseXmmLoadAndClearUpper true {ARCH product}bool UseXmmRegToRegMoveAll false {ARCH product}bool VMThreadHintNoPreempt false {product}intx VMThreadPriority -1 {product}intx VMThreadStackSize 0 {pd product}intx ValueMapInitialSize 11 {C1 product}intx ValueMapMaxLoopSize 8 {C1 product}intx ValueSearchLimit 1000 {C2 product}bool VerifyMergedCPBytecodes true {product}bool VerifySharedSpaces false {product}intx WorkAroundNPTLTimedWaitHang 1 {product}uintx YoungGenerationSizeIncrement 20 {product}uintx YoungGenerationSizeSupplement 80 {product}uintx YoungGenerationSizeSupplementDecay 8 {product}uintx YoungPLABSize 4096 {product}bool ZeroTLAB false {product}intx hashCode 5 {product}Process finished with exit code 09.4 查看所有的参数的最终值 9.5 查看某个参数的指令
jps 查看当前运行的所有进程
// 查看某个进程的SurvivorRatio参数
jinfo -flag SurvivorRatio 进程id十、截图示例
10.1 new对象指令 10.2 jdk7的gc信息 10.3 jdk8的gc信息
