I have a container running a Spring Boot microservice. I am using openjdk version "1.8.0_212" under OpenJDK Runtime Environment (IcedTea 3.12.0) (Alpine 8.212.04-r0) When I use -XX:+PrintFlagsFinal flag and print the JVM parameters I expected to see
-XX:+UseParallelGC as true
But to my surprise none of the 4 collectors (-XX:+UseSerialGC,-XX:+UseParallelGC,-XX:+UseConcMarkSweepGC,–XX:+UseG1GC) were active.
Shown below is my dockerfile:
FROM openjdk:8-jdk-alpine
ADD ./demo-0.0.1-SNAPSHOT.jar /usr/src/factorial/
WORKDIR /usr/src/factorial
EXPOSE 8080
CMD java $JAVA_OPTIONS -jar demo-0.0.1-SNAPSHOT.jar
I'm running this using:
docker run -d --rm --name factorialorialContainer --memory='512m' --cpus=2 -p 8080:8080 -e JAVA_OPTIONS="$(cat /Users/sulekahelmini/Documents/fyp/fyp_work/MLscripts/$3)" suleka96/factorial:latest
The flags_base.txt
-Xms512m -Xmx512m -XX:+PrintFlagsFinal -version
This is part of the output of -XX:+PrintFlagsFinal
intx UnguardOnExecutionViolation = 0 {product}
bool UnlinkSymbolsALot = false {product}
bool Use486InstrsOnly = false {ARCH product}
bool UseAES = true {product}
bool UseAESIntrinsics = true {product}
intx UseAVX = 2 {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 = true {ARCH product}
bool UseAltSigs = false {product}
bool UseAutoGCSelectPolicy = false {product}
bool UseBMI1Instructions = true {ARCH product}
bool UseBMI2Instructions = true {ARCH product}
bool UseBiasedLocking = true {product}
bool UseBimorphicInlining = true {C2 product}
bool UseBoundThreads = true {product}
bool UseCLMUL = true {ARCH product}
bool UseCMSBestFit = true {product}
bool UseCMSCollectionPassing = true {product}
bool UseCMSCompactAtFullCollection = true {product}
bool UseCMSInitiatingOccupancyOnly = false {product}
bool UseCRC32Intrinsics = true {product}
bool UseCodeCacheFlushing = true {product}
bool UseCompiler = true {product}
bool UseCompilerSafepoints = true {product}
bool UseCompressedClassPointers := true {lp64_product}
bool UseCompressedOops := true {lp64_product}
bool UseConcMarkSweepGC = false {product}
bool UseCondCardMark = false {C2 product}
bool UseContainerSupport = true {product}
bool UseCountLeadingZerosInstruction = true {ARCH product}
bool UseCountTrailingZerosInstruction = true {ARCH product}
bool UseCountedLoopSafepoints = false {C2 product}
bool UseCounterDecay = true {product}
bool UseDivMod = true {C2 product}
bool UseDynamicNumberOfGCThreads = false {product}
bool UseFPUForSpilling = true {C2 product}
bool UseFastAccessorMethods = false {product}
bool UseFastEmptyMethods = false {product}
bool UseFastJNIAccessors = true {product}
bool UseFastStosb = true {ARCH product}
bool UseG1GC = false {product}
bool UseGCLogFileRotation = false {product}
bool UseGCOverheadLimit = true {product}
bool UseGCTaskAffinity = false {product}
bool UseHeavyMonitors = false {product}
bool UseHugeTLBFS = 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 UseLinuxPosixThreadCPUClocks = true {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 = true {C2 product}
bool UseMontgomerySquareIntrinsic = true {C2 product}
bool UseMulAddIntrinsic = true {C2 product}
bool UseMultiplyToLenIntrinsic = true {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 UseOprofile = false {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 = true {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}
bool UseSHM = false {product}
intx UseSSE = 4 {product}
bool UseSSE42Intrinsics = true {product}
bool UseSerialGC = false {product}
bool UseSharedSpaces = false {product}
bool UseSignalChaining = true {product}
bool UseSquareToLenIntrinsic = true {C2 product}
bool UseStoreImmI16 = false {ARCH product}
bool UseStringDeduplication = false {product}
bool UseSuperWord = true {C2 product}
bool UseTLAB = true {pd product}
bool UseThreadPriorities = true {pd product}
bool UseTransparentHugePages = false {product}
bool UseTypeProfile = true {product}
bool UseTypeSpeculation = true {C2 product}
bool UseUnalignedLoadStores = false {ARCH product}
bool UseVMInterruptibleIO = false {product}
bool UseXMMForArrayCopy = true {product}
bool UseXmmI2D = false {ARCH product}
bool UseXmmI2F = false {ARCH product}
bool UseXmmLoadAndClearUpper = true {ARCH product}
bool UseXmmRegToRegMoveAll = true
After running
jcmd [pid] VM.flags
I am getting the below output which also does not specify a collector:
-XX:CICompilerCount=2 -XX:InitialHeapSize=536870912 -XX:MaxHeapSize=536870912 -XX:MaxNewSize=178913280 -XX:MinHeapDeltaBytes=196608 -XX:NewSize=178913280 -XX:OldSize=357957632 -XX:+StartAttachListener -XX:+UseCompressedClassPointers -XX:+UseCompressedOops
What Is happening here? Is there anything I'm doing wrong?
In JDK 8, if no Use*GC
flags are set, and if Parallel GC hasn't been chosen ergonomically, then Serial GC is used.
The fix for JDK-8068582 automatically turns on -XX:+UseSerialGC
in such cases since JDK 9.
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