/in/monicabeckwith12PerformanceEngineering3?2016CodeKaram3PerformanceAPerformanceAnalysisPerformanceEngineeringPerformanceRequirements&TestPlan&Development4?2016CodeKaramDesignImplementation?2016CodeKaramDesignImplementationRequirementsPerformanceRequirements&TestPlan&DevelopmentPerformanceAnalysis5PerformanceRequirements6?2016CodeKaram6Throughput?Capacity?Responsetimes?Throughput?Capacity?Responsetimes?PerformanceRequirementsAvailability?Footprint?PerformanceAnalysis78?2016CodeKaramProfilingMonitoring?2016CodeKaramProfilingMonitoringSystemUnderTestUtilization,LockStats,…Application,System,Memory,…PerformanceAnalysisAnalyzinglogs9JVMPerformanceEngineering?2016JavaJavaAPIJREJavaJavaApplicationClassClassloaderRuntimeJITCompilerJavaVMOS+HardwareGC?2016CodeKaramJITCompiler?2016CodeKaramJITCompiler+RuntimeJavaDevelopmentKitGarbageCollector/CollectionStudy,Analyze,TuneJavaAPIGarbageCollectionPerformanceEngineering?2016Online&OfflineGCOnline&OfflineGCMonitoringJVMMonitoringHeapProfilingApplicationProfilingGCPerformanceEngineeringProcess&PlotGClogsGarbageCollection-Facts,Trade-OffsAndAlgorithms?2016GCFact!?GCcanNOTeliminateyourmemoryleaks!?GC(andheapdump)canprovideaninsightintoyourapplication.?2016?2016CodeKaram?2016GCFact!ThroughputandlatencyarethetwomaindriverstowardsrefinementofGCalgorithms.?2016CodeKaramGenerationalConcurrentThreadsYoungOld?2016CodeKaramGenerationalConcurrentThreadsYoungOldMaximizeThroughputParallelWorkStop-the-worldThreads?2016PauseonlywhenneededNoPauseonlywhenneededNo/PartialCompactionLatencySensitiveConcurrentMarking/SweepingReduceReducestop-the-worldGCpausetime?2016Let’slookatOpenJDKHotSpotGCs:)?2016MaximizerParallelMaximizerParallelGCSensitiveThroughputCMSGCG1GCLatency?2016GCFact!AllGCsinOpenJDKHotSpotaregenerational.?2016?2016CodeKaramYoungGenerationOldGenerationEdenSurvivors?2016?2016CodeKaramEdenSurvivorsAllocationsYoungGenerationFastPathAllocation==Lock-FreeAllocation==ThreadsAllocateIntoTheirLocalAllocationBuffer(LAB)s??2016CodeKaramEdenTLABTLABTLABTLABTLABTLABTLAB=ThreadLocalAllocationBuffer?20163TLABTLAB3TLABTLABTLABTLABTLABThreadThreadThreadThreadThread0Eden1Eden44?2016?2016CodeKaramEdenSurvivorsAllocationsYoungGeneration?2016?2016CodeKaramEdenSurvivorsAllocationsYoungGenerationGarbageCollection-Reclamation.?2016YoungGenerationOldGenerationEdenEden?2016YoungGenerationOldGenerationDifferentDifferentGCAlgorithmsforOpenJDKHotspot*SimilarGCAlgorithmsforOpenJDKHotSpotAlwayscollectedinitsentirety?2016YoungGenerationOldGenerationDifferentGCAlgorithmsforDifferentGCAlgorithmsforOpenJDKHotspotAlgorithmsforOpenJDKHotSpotAlwayscollectedinitsentiretyYoungGarbageCollection==ReclamationViaScavenging?2016RootSetYoungGenerationOldGeneration??2016CodeKaramYoungGenerationEdenSurvivor??2016CodeKaramYoungGenerationEdenSurvivor??2016CodeKaramYoungGenerationEdenSurvivorOldGarbageCollection==DifferentGCAlgorithms?2016CodeKaramThe?2016CodeKaramYoungGenerationOldGenerationMultiMulti-Threaded-EntireHeapMarked,SweptandCompactedinitsentiretyMulti-ThreadedAlwayscollectedinitsentirety?2016Multi-ThreadedMulti-Multi-ThreadedMulti-Threaded-EntireHeapMarked,SweptandCompactedinitsentiretyYoungGenerationOldGenerationAlwayscollectedinitsentirety?2016GarbageCollection-ReclamationviaParallelMark-CompactRootSetYoungGenerationOldGeneration?2016GarbageCollection-ReclamationviaParallelMark-CompactOldGeneration?2016GarbageCollection-ReclamationviaParallelMark-CompactOldGeneration?2016OldOldGenerationGarbageCollection-ReclamationviaParallelMark-Compactsourceregiondestinationregion?2016OldOldGenerationGarbageCollection-ReclamationviaParallelMark-Compactsourceregiondestinationregion?2016OldOldGenerationGarbageCollection-ReclamationviaParallelMark-Compactsourceregionsourceregiondestinationregion?2016OldOldGenerationGarbageCollection-ReclamationviaParallelMark-Compactsourceregionsourceregiondestinationregion?2016GarbageCollection-ReclamationviaParallelMark-CompactOldGeneration?2016YoungGenerationOldGenerationMultiMulti-Threaded-MostlyConcurrentMarkedandentiretyMulti-ThreadedSweptinitsAlwayscollectedinitsentirety?2016YoungGenerationOldGenerationMultiMulti-Threaded-MostlyConcurrentMarkedandSweptinitsentiretyMulti-ThreadedAlwayscollectedAlwayscollectedinits?2016YoungGenerationOldGenerationMultiMulti-Threaded-MostlyConcurrentMarkedandSweptinitsentiretyMulti-ThreadedAlwayscollectedinAlwayscollectedinitsentirety?2016CodeKaramGarbageCollection-?2016CodeKaramReclamationviaMark-SweepFreeListOldGenerationOldGeneration?2016CodeKaramOldGeneration?2016CodeKaramReclamationviaMark-SweepFreeList?2016GCFact!Allnon/partialcompactingGCsinOpenJDKHotSpotfallback*toafullycompactingstop-the-worldgarbagecollectioncalledthe“full”GC.*TuningcanhelpavoidorpostponefullGCsinmanycases.?2016GarbageCollection-ReclamationviaMark-Sweep-CompactYoungGenerationOldGenerationSingleSingleThreaded-EntireHeapMarked,SweptandCompactedinitsentirety?2016GarbageCollection-ReclamationviaMark-Sweep-CompactYoungGenerationOldGenerationSingleThreaded-EntireHeapMarked,SweptandCompactedinitsentiretyWhatAboutGarbageFirstGC???2016CodeKaramContiguousJavaHeapFreeRegionNon-FreeRegion?2016CodeKaramEdenOldEdenOldTheGarbageFirst?2016CodeKaramEdenOldEdenOldSurvivorSurvivorOOldHHumongous61?2016CodeKaramTheGarbageFirstCollectorE.g.:CurrentEEdenOOldheapconfiguration-SurvSurvivorOOldEEdenOld62?2016CodeKaramEdenOldE.g.:DuringEdenOldE.g.:Duringayoungcollection-TheGarbageFirstCollectorSurvSurvivorOOldEEdenOld63?2016CodeKaramOldOldOldTheGarbageFirstCollectorE.g.:Afterayoungcollection-OlOldOOldSurSurvivor64?2016CodeKaramOldEdenSurOldEdenSurvivorOldTheGarbageFirstCollectorE.g.:Currentheapconfiguration-OlOldOOldEEdenOOld?2016CodeKaramOldEden?2016CodeKaramOldEdenSurvivorOldTheGarbageFirstCollectorOldE.g.:Reclamationofagarbage-filledregionduringthecleanupphase-OldOOldEEdenOOld?2016CodeKaramOld?2016CodeKaramOldEdenOldTheGarbageFirstCollectorOldE.g.:Reclamationofagarbage-filledregionduringthecleanupphase-OldOOldEEdenSurSurvivor67?2016CodeKaramOldEOldEdenOldTheGarbageFirstCollectorE.g.:Currentheapconfiguration-OlOldOOldEEdenSurSurvivor?2016CodeKaramOldE?2016CodeKaramOldEdenOldTheGarbageFirstCollectorE.g.:E.g.:DuringamixedOlOldOOldEEdenSurSurvivor69?2016CodeKaramSurvSurvivorOldTheGarbageFirstCollectorE.g.:Afteramixedcollection-OOldOOldimeinmillisecondsInitiatingHeapOccupancyPercent?2016CodeKaramimeinmillisecondsInitiatingHeapOccupancyPercent?2016CodeKaram034153416.33417.23418.4341934223423.43432.23433.23436.83437.63438.93440ampsYoungCollectionInitialMarkRemarkCleanupMixedCollectionFinally,Let’sTalkAboutTuning!:)TuningGCForThroughputOrForLatency??GCElapsedTimeOrGCOverheadGCElapsedTimeindicatedtheamountoftimeittakestoexecutestoptheworldGCeventsThehighertheGCelapsedtime-thelowertheapplicationresponsivenessduetotheGCinducedlatencies74?2016CodeKaram??2016CodeKaramOverheadisanindicationofthefrequencyofstoptheworldGCevents.Themorefrequent