第2节课作业实践.docx
第2节课作业实践工、本机使用GlGC启动一个程序，仿照课上案例分析一下JVM情况实践使用我之前写的一个WaiterSerViCeAPPliCatiOn进行演示，这是一个RestService,用于处理咖啡的订单。1 .在IDEA上将此project的VMoptions设置为：-XX:+USeGIGC-XX:MaXGCPaUSeMiIIiS=50ffiRufVDebugConfigurations÷-¾H工VAppScation>/TcfnptetesNameWdftefServiceApfMicdtionAllowparallelrunConfigurationCodeCoveragelogs×StoreasprojectfileMdinc3ss:c<xn«xMnple<omplexcontrollef.Wite<ServiceAppliCt>onVMoptions：Programarguments：-XX:WKlCC-XX:>UxCCPauMM11is-30Workingdirectory:Environmentvariables:Redirectinputfrom:C:DaUCodeGitHubSpnngFamilyChapter6cocnplex-cotrollerUsedastotmodule1COmPleXYontrOIIefIndudedependefwswithPrvkle<scopeJRE:Default二-Shortencommandlineuser-localdefaultnone，EnaWccapturingformsnapshotsBeforelaunchBwldOKCancel÷2 .启动程序。3 .在IDEA的Terminal中执行jps,根据名字可以发现PID为“084。C:DataCodeGitHubSpringFamilyChapter6conplex-controll,er>jps119712；28672Launcher23824RemoteMavenServer3622324Jps；17884WaiterserviceApplicationh.C:DataCode6itHubSpringFamilyChapter6coRplex-controller>4 .执行命令：jmap-heap17084,可能因为我电脑上安装的是java11,此命令不好使C:DataCodeGitHubSpringFamilyChapter6coBplex-controller>jpsI19712i26672Launcher:23824RemoteHavenServr3622324JpsI17884WaiterserviceAopllcatlonC:DataCodeGitHubSpringFanilyChapter6conplex-controller>jnap-heap17884Error:-heapoptionusedCannotconnecttocoredumporremotedebugserver.Usejhsdbj18pInsteadC:DataCodeGitHubSpringFamilyChapter6conple×-controlaler>5 .根据提示，最终执行命令：jhsdbjmap-heaP-Pidl7084。结果如下：C:DataCodeGitHubSpringFamilyChapter6comple×-controller>jhsdbjmap-heap-pid17084AttachingtoprocessID17084,pleasewait.Debuggerattachedsuccessfully.Servercompilerdetected.JVMversionis11.0.2+9-LTSusingthread-localobjectallocation.Garbage-First(Gl)GCwith8thread(s)=40=70 (2000.0MB)HeapConfiguration:MinHeapFreeRatioMaxHeapFreeRatio=(1.2812MB)=(1200.0MB)=(5.21875MB)=2=8=(20.796875MB)MaxHeapSizeNewSizeMaxNewSizeOIdSizeNewRatioSurvivorRatioMetaspaceSizeCompressedciassSpaceSize=(1024.0MB)MaxMetaspaceSize=415MBGlHeapRegionSize=(1.0MB)HeapUsage:GlHeap:regions=2000capacity=(2000.0MB)used=(67.94MB)free=(1932.9MB)3.047%usedGlYoungGeneration:EdenSpace:regions=48capacity=(89.0MB)used=(48.0MB)free=(41.0MB)53.92%usedSurvivorSpace:regions=7capacity=(7.0MB)used=(7.0MB)free=O(0.0MB)1OO.O%usedGlOldGeneration:regions=14capacity=(56.0MB)used=(11.938MB)free=(44.906MB)21.104%used6 .从上面的结果可以发现：Garbage-First(Gl)GCwith8thread(s)1已经使用了GlGC,因为我的笔记本有8个CPU,所以是8个线程。MaxHeapSize=(2000.0MB),是我笔记本8G内存的四分之一。MaxNewSizeNewSizeOIdSize=(1200.0MB),是MaxHeapSize的60%0=(1.2812MB),年轻代初始值为1.3MB。：(5.21875MB),老年代初始值为5.2MB,GlHeapRegionSize=(1.0MB),2G内存，2048个region,每个region1MB。以新生儿为例:使用了48个region,所有used为48MBoEdenSpace:regions=48capacity=(89.0MB)used=(48.0MB)free=(41.0MB)53.92%used7 .打开ViSUalVM,执行一次PerfOrmGC。注：Java11的jdk中不再包含jvisualvm,需要从下载。7 VhUaIVM 244Fe AppIiCAbom View TooH Window Help中禽事检曲包96-5zln-j Local MitVM器 lde(pd l”12)© "g.)(brMCLidAjnaMc.fi(vrRmo<M*VoftSarVS623024)A oqj.)e<brnskp,cmdnelunk<r (p0 20672)叁 Remote VM Coftdumps J6R Snptts Stsoom.exampleompcontroter.WterSe<vceppkicatn (p<d 1704)×(0 Owrww Monitor grMds lQ, Sempter Cpromff O com.cxamplcxompl<×controllcr.WditcfS<rvkcApplkdtion (id 17084)Mentor0 CW 团 Memory Q Ombvs () ThrcedsUptae:27mm 27 etcBU*"l> y： 0JGC activity: 0.0¼UMH-«%0% *> -»1""»务办 20*9:57530”fcS7H0FH CFU u9 CC MtfvffyI Perform CC I M8 DumpMMp MtMpC* 3:1H.33M UMd: S4,"6,7X tMaX:44X.3X,032BTotal loaded: 11.624Shar<Ml IOXM: OTotal 3k>M¼d: OShMd unloaded: OIOJJOOsmOllT，57XXPMRgQPM9Pi40PM Totti IOMldCteMM HSMrV 2X8”，llv: 29D mm on: ?5IgPl: 29Total Urtd: 348.观察jstat-gcutil17084100O100O的执行情况：fflEk£<MVwHeviQMeCedeAnalytf?ef4Ctorcomplex<ofitronef;rcm.1jvacomCnnIPieBuidRunIocbVCSWindoWQBNegatorHelpConX)UrtrO30W*erSefv>ceAppiatc.yaiefCtr.GcZ*E×!QtWa<te<S<fvceApc>lat)onCOGIPrqleaO÷-GWAUyfSc?CCAaI-'lTefme1：l<xa+U-,C:DataCodeGitHubSpringFamilyChapter6co<nplex-controller>jstat-gcutil17841：Lm1SSlEOMCCSYGCYGCTFGCFGCTCGCCGCTGCTOO.1.73.321.1197.7892.59l.91.6.16.17.1.73.321.1197.7892.59l.91.6.16.17.l.74.1621.1197.7892.59l.91.6.l60.17.l.74.1621.1197.7892.59l.091.68.16.17.0l.74.1621.1197.7892.59l.910.6.16B.177.6.2697.2191.21l.91
