/* * Copyright (c) 1997, 2025, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. * */ #ifndef SHARE_RUNTIME_GLOBALS_HPP #define SHARE_RUNTIME_GLOBALS_HPP #include "compiler/compiler_globals_pd.hpp" #include "runtime/globals_shared.hpp" #include "utilities/align.hpp" #include "utilities/globalDefinitions.hpp" #include "utilities/macros.hpp" #include CPU_HEADER(globals) #include OS_HEADER(globals) #include OS_CPU_HEADER(globals) // develop flags are settable / visible only during development and are constant in the PRODUCT version // product flags are always settable / visible // develop_pd/product_pd flags are the same as develop/product, except that their default values // are specified in platform-dependent header files. // Flags must be declared with the following number of parameters: // non-pd flags: // (type, name, default_value, doc), or // (type, name, default_value, extra_attrs, doc) // pd flags: // (type, name, doc), or // (type, name, extra_attrs, doc) // A flag must be declared with one of the following types: // bool, int, uint, intx, uintx, size_t, ccstr, ccstrlist, double, or uint64_t. // The type "ccstr" and "ccstrlist" are an alias for "const char*" and is used // only in this file, because the macrology requires single-token type names. // The optional extra_attrs parameter may have one of the following values: // DIAGNOSTIC, EXPERIMENTAL, or MANAGEABLE. Currently extra_attrs can be used // only with product/product_pd flags. // // DIAGNOSTIC options are not meant for VM tuning or for product modes. // They are to be used for VM quality assurance or field diagnosis // of VM bugs. They are hidden so that users will not be encouraged to // try them as if they were VM ordinary execution options. However, they // are available in the product version of the VM. Under instruction // from support engineers, VM customers can turn them on to collect // diagnostic information about VM problems. To use a VM diagnostic // option, you must first specify +UnlockDiagnosticVMOptions. // (This master switch also affects the behavior of -Xprintflags.) // // EXPERIMENTAL flags are in support of features that may not be // an officially supported part of a product, but may be available // for experimenting with. They could, for example, be performance // features that may not have undergone full or rigorous QA, but which may // help performance in some cases and released for experimentation // by the community of users and developers. This flag also allows one to // be able to build a fully supported product that nonetheless also // ships with some unsupported, lightly tested, experimental features. // Refer to the documentation of any products using this code for details // on support and fitness for production. // Like the UnlockDiagnosticVMOptions flag above, there is a corresponding // UnlockExperimentalVMOptions flag, which allows the control and // modification of the experimental flags. // // Nota bene: neither diagnostic nor experimental options should be used casually, // Refer to the documentation of any products using this code for details. // // MANAGEABLE flags are writeable external product flags. // They are dynamically writeable through the JDK management interface // (com.sun.management.HotSpotDiagnosticMXBean API) and also through JConsole. // These flags are external exported interface (see CSR). The list of // manageable flags can be queried programmatically through the management // interface. // // A flag can be made as "manageable" only if // - the flag is defined in a CSR request as an external exported interface. // - the VM implementation supports dynamic setting of the flag. // This implies that the VM must *always* query the flag variable // and not reuse state related to the flag state at any given time. // - you want the flag to be queried programmatically by the customers. // // // range is a macro that will expand to min and max arguments for range // checking code if provided - see jvmFlagLimit.hpp // // constraint is a macro that will expand to custom function call // for constraint checking if provided - see jvmFlagLimit.hpp // Default and minimum StringTable and SymbolTable size values // Must be powers of 2 const size_t defaultStringTableSize = NOT_LP64(1024) LP64_ONLY(65536); const size_t minimumStringTableSize = 128; const size_t defaultSymbolTableSize = 32768; // 2^15 const size_t minimumSymbolTableSize = 1024; #ifdef _LP64 #define LP64_RUNTIME_FLAGS(develop, \ develop_pd, \ product, \ product_pd, \ range, \ constraint) \ \ product(bool, UseCompressedOops, false, \ "Use 32-bit object references in 64-bit VM. " \ "lp64_product means flag is always constant in 32 bit VM") \ \ product(bool, UseCompressedClassPointers, true, \ "(Deprecated) Use 32-bit class pointers in 64-bit VM. " \ "lp64_product means flag is always constant in 32 bit VM") \ \ product(bool, UseCompactObjectHeaders, false, \ "Use compact 64-bit object headers in 64-bit VM") \ \ product(int, ObjectAlignmentInBytes, 8, \ "Default object alignment in bytes, 8 is minimum") \ range(8, 256) \ constraint(ObjectAlignmentInBytesConstraintFunc, AtParse) #else // !_LP64 #define LP64_RUNTIME_FLAGS(develop, \ develop_pd, \ product, \ product_pd, \ range, \ constraint) const bool UseCompressedOops = false; const bool UseCompressedClassPointers = false; const bool UseCompactObjectHeaders = false; const int ObjectAlignmentInBytes = 8; #endif // _LP64 #define RUNTIME_FLAGS(develop, \ develop_pd, \ product, \ product_pd, \ range, \ constraint) \ \ develop(bool, CheckCompressedOops, true, \ "Generate checks in encoding/decoding code in debug VM") \ \ product(uintx, HeapSearchSteps, 3 PPC64_ONLY(+17), \ "Heap allocation steps through preferred address regions to find" \ " where it can allocate the heap. Number of steps to take per " \ "region.") \ range(1, max_uintx) \ \ product(uint, HandshakeTimeout, 0, DIAGNOSTIC, \ "If nonzero set a timeout in milliseconds for handshakes") \ \ product(bool, AlwaysSafeConstructors, false, EXPERIMENTAL, \ "Force safe construction, as if all fields are final.") \ \ product(bool, UnlockDiagnosticVMOptions, trueInDebug, DIAGNOSTIC, \ "Enable normal processing of flags relating to field diagnostics")\ \ product(bool, UnlockExperimentalVMOptions, false, EXPERIMENTAL, \ "Enable normal processing of flags relating to experimental " \ "features") \ \ product(bool, JavaMonitorsInStackTrace, true, \ "Print information about Java monitor locks when the stacks are " \ "dumped") \ \ product_pd(bool, UseLargePages, \ "Use large page memory") \ \ product_pd(bool, UseLargePagesIndividualAllocation, \ "Allocate large pages individually for better affinity") \ \ develop(bool, LargePagesIndividualAllocationInjectError, false, \ "Fail large pages individual allocation") \ \ product(bool, UseNUMA, false, \ "Use NUMA if available") \ \ product(bool, UseNUMAInterleaving, false, \ "Interleave memory across NUMA nodes if available") \ \ product(size_t, NUMAInterleaveGranularity, 2*M, \ "Granularity to use for NUMA interleaving on Windows OS") \ constraint(NUMAInterleaveGranularityConstraintFunc, AtParse) \ \ product(uintx, NUMAChunkResizeWeight, 20, \ "Percentage (0-100) used to weight the current sample when " \ "computing exponentially decaying average for " \ "AdaptiveNUMAChunkSizing") \ range(0, 100) \ \ product(size_t, NUMASpaceResizeRate, 1*G, \ "Do not reallocate more than this amount per collection") \ range(0, max_uintx) \ \ product(bool, UseAdaptiveNUMAChunkSizing, true, \ "Enable adaptive chunk sizing for NUMA") \ \ product(bool, NUMAStats, false, \ "Print NUMA stats in detailed heap information") \ \ product(bool, UseAES, false, \ "Control whether AES instructions are used when available") \ \ product(bool, UseFMA, false, \ "Control whether FMA instructions are used when available") \ \ product(bool, UseSHA, false, \ "Control whether SHA instructions are used when available") \ \ product(bool, UseGHASHIntrinsics, false, DIAGNOSTIC, \ "Use intrinsics for GHASH versions of crypto") \ \ product(bool, UseBASE64Intrinsics, false, \ "Use intrinsics for java.util.Base64") \ \ product(bool, UsePoly1305Intrinsics, false, DIAGNOSTIC, \ "Use intrinsics for sun.security.util.math.intpoly") \ product(bool, UseIntPolyIntrinsics, false, DIAGNOSTIC, \ "Use intrinsics for sun.security.util.math.intpoly.MontgomeryIntegerPolynomialP256") \ \ product(size_t, LargePageSizeInBytes, 0, \ "Maximum large page size used (0 will use the default large " \ "page size for the environment as the maximum)") \ range(0, max_uintx) \ \ product(size_t, LargePageHeapSizeThreshold, 128*M, \ "Use large pages if maximum heap is at least this big") \ range(0, max_uintx) \ \ product(bool, ForceTimeHighResolution, false, \ "Using high time resolution (for Win32 only)") \ \ develop(bool, TracePcPatching, false, \ "Trace usage of frame::patch_pc") \ \ develop(bool, TraceRelocator, false, \ "Trace the bytecode relocator") \ \ \ product(bool, SafepointALot, false, DIAGNOSTIC, \ "Generate a lot of safepoints. This works with " \ "GuaranteedSafepointInterval") \ \ product(bool, HandshakeALot, false, DIAGNOSTIC, \ "Generate a lot of handshakes. This works with " \ "GuaranteedSafepointInterval") \ \ product_pd(bool, BackgroundCompilation, \ "A thread requesting compilation is not blocked during " \ "compilation") \ \ product(bool, MethodFlushing, true, \ "Reclamation of compiled methods") \ \ develop(bool, VerifyStack, false, \ "Verify stack of each thread when it is entering a runtime call") \ \ product(bool, ForceUnreachable, false, DIAGNOSTIC, \ "Make all non code cache addresses to be unreachable by " \ "forcing use of 64bit literal fixups") \ \ develop(bool, TraceDerivedPointers, false, \ "Trace traversal of derived pointers on stack") \ \ develop(bool, TraceCodeBlobStacks, false, \ "Trace stack-walk of codeblobs") \ \ develop(bool, PrintRewrites, false, \ "Print methods that are being rewritten") \ \ product(bool, UseInlineCaches, true, \ "Use Inline Caches for virtual calls ") \ \ product(bool, InlineArrayCopy, true, DIAGNOSTIC, \ "Inline arraycopy native that is known to be part of " \ "base library DLL") \ \ product(bool, InlineObjectHash, true, DIAGNOSTIC, \ "Inline Object::hashCode() native that is known to be part " \ "of base library DLL") \ \ product(bool, InlineNatives, true, DIAGNOSTIC, \ "Inline natives that are known to be part of base library DLL") \ \ product(bool, InlineMathNatives, true, DIAGNOSTIC, \ "Inline SinD, CosD, etc.") \ \ product(bool, InlineClassNatives, true, DIAGNOSTIC, \ "Inline Class.isInstance, etc") \ \ product(bool, InlineThreadNatives, true, DIAGNOSTIC, \ "Inline Thread.currentThread, etc") \ \ product(bool, InlineUnsafeOps, true, DIAGNOSTIC, \ "Inline memory ops (native methods) from Unsafe") \ \ product(bool, UseAESIntrinsics, false, DIAGNOSTIC, \ "Use intrinsics for AES versions of crypto") \ \ product(bool, UseAESCTRIntrinsics, false, DIAGNOSTIC, \ "Use intrinsics for the paralleled version of AES/CTR crypto") \ \ product(bool, UseChaCha20Intrinsics, false, DIAGNOSTIC, \ "Use intrinsics for the vectorized version of ChaCha20") \ \ product(bool, UseKyberIntrinsics, false, DIAGNOSTIC, \ "Use intrinsics for the vectorized version of Kyber") \ \ product(bool, UseDilithiumIntrinsics, false, DIAGNOSTIC, \ "Use intrinsics for the vectorized version of Dilithium") \ \ product(bool, UseMD5Intrinsics, false, DIAGNOSTIC, \ "Use intrinsics for MD5 crypto hash function") \ \ product(bool, UseSHA1Intrinsics, false, DIAGNOSTIC, \ "Use intrinsics for SHA-1 crypto hash function. " \ "Requires that UseSHA is enabled.") \ \ product(bool, UseSHA256Intrinsics, false, DIAGNOSTIC, \ "Use intrinsics for SHA-224 and SHA-256 crypto hash functions. " \ "Requires that UseSHA is enabled.") \ \ product(bool, UseSHA512Intrinsics, false, DIAGNOSTIC, \ "Use intrinsics for SHA-384 and SHA-512 crypto hash functions. " \ "Requires that UseSHA is enabled.") \ \ product(bool, UseSHA3Intrinsics, false, DIAGNOSTIC, \ "Use intrinsics for SHA3 crypto hash function. " \ "Requires that UseSHA is enabled.") \ \ product(bool, UseCRC32Intrinsics, false, DIAGNOSTIC, \ "use intrinsics for java.util.zip.CRC32") \ \ product(bool, UseCRC32CIntrinsics, false, DIAGNOSTIC, \ "use intrinsics for java.util.zip.CRC32C") \ \ product(bool, UseAdler32Intrinsics, false, DIAGNOSTIC, \ "use intrinsics for java.util.zip.Adler32") \ \ product(bool, UseVectorizedMismatchIntrinsic, false, DIAGNOSTIC, \ "Enables intrinsification of ArraysSupport.vectorizedMismatch()") \ \ product(bool, UseVectorizedHashCodeIntrinsic, false, DIAGNOSTIC, \ "Enables intrinsification of ArraysSupport.vectorizedHashCode()") \ \ product(bool, UseCopySignIntrinsic, false, DIAGNOSTIC, \ "Enables intrinsification of Math.copySign") \ \ product(bool, UseSignumIntrinsic, false, DIAGNOSTIC, \ "Enables intrinsification of Math.signum") \ \ product_pd(bool, DelayCompilerStubsGeneration, DIAGNOSTIC, \ "Use Compiler thread for compiler's stubs generation") \ \ product(ccstrlist, DisableIntrinsic, "", DIAGNOSTIC, \ "do not expand intrinsics whose (internal) names appear here") \ constraint(DisableIntrinsicConstraintFunc,AfterErgo) \ \ product(ccstrlist, ControlIntrinsic, "", DIAGNOSTIC, \ "Control intrinsics using a list of +/- (internal) names, " \ "separated by commas") \ constraint(ControlIntrinsicConstraintFunc,AfterErgo) \ \ develop(bool, TraceCallFixup, false, \ "Trace all call fixups") \ \ develop(bool, DeoptimizeALot, false, \ "Deoptimize at every exit from the runtime system") \ \ develop(ccstrlist, DeoptimizeOnlyAt, "", \ "A comma separated list of bcis to deoptimize at") \ \ develop(bool, DeoptimizeRandom, false, \ "Deoptimize random frames on random exit from the runtime system")\ \ develop(bool, ZombieALot, false, \ "Create non-entrant nmethods at exit from the runtime system") \ \ develop(bool, WalkStackALot, false, \ "Trace stack (no print) at every exit from the runtime system") \ \ develop(bool, DeoptimizeObjectsALot, false, \ "For testing purposes concurrent threads revert optimizations " \ "based on escape analysis at intervals given with " \ "DeoptimizeObjectsALotInterval=n. The thread count is given " \ "with DeoptimizeObjectsALotThreadCountSingle and " \ "DeoptimizeObjectsALotThreadCountAll.") \ \ develop(uint64_t, DeoptimizeObjectsALotInterval, 5, \ "Interval for DeoptimizeObjectsALot.") \ range(0, max_jlong) \ \ develop(int, DeoptimizeObjectsALotThreadCountSingle, 1, \ "The number of threads that revert optimizations based on " \ "escape analysis for a single thread if DeoptimizeObjectsALot " \ "is enabled. The target thread is selected round robin." ) \ range(0, max_jint) \ \ develop(int, DeoptimizeObjectsALotThreadCountAll, 1, \ "The number of threads that revert optimizations based on " \ "escape analysis for all threads if DeoptimizeObjectsALot " \ "is enabled." ) \ range(0, max_jint) \ \ develop(bool, VerifyLastFrame, false, \ "Verify oops on last frame on entry to VM") \ \ product(bool, SafepointTimeout, false, \ "Time out and warn or fail after SafepointTimeoutDelay " \ "milliseconds if failed to reach safepoint") \ \ product(bool, AbortVMOnSafepointTimeout, false, DIAGNOSTIC, \ "Abort upon failure to reach safepoint (see SafepointTimeout)") \ \ product(uint64_t, AbortVMOnSafepointTimeoutDelay, 0, DIAGNOSTIC, \ "Delay in milliseconds for option AbortVMOnSafepointTimeout") \ range(0, max_jlong) \ \ product(bool, AbortVMOnVMOperationTimeout, false, DIAGNOSTIC, \ "Abort upon failure to complete VM operation promptly") \ \ product(intx, AbortVMOnVMOperationTimeoutDelay, 1000, DIAGNOSTIC, \ "Delay in milliseconds for option AbortVMOnVMOperationTimeout") \ range(0, max_intx) \ \ product(bool, MaxFDLimit, true, \ "Bump the number of file descriptors to maximum (Unix only)") \ \ product(bool, LogEvents, true, DIAGNOSTIC, \ "Enable the various ring buffer event logs") \ \ product(int, LogEventsBufferEntries, 20, DIAGNOSTIC, \ "Number of ring buffer event logs") \ range(1, NOT_LP64(1*K) LP64_ONLY(1*M)) \ \ product(bool, BytecodeVerificationRemote, true, DIAGNOSTIC, \ "Enable the Java bytecode verifier for remote classes") \ \ product(bool, BytecodeVerificationLocal, false, DIAGNOSTIC, \ "Enable the Java bytecode verifier for local classes") \ \ develop(bool, VerifyStackAtCalls, false, \ "Verify that the stack pointer is unchanged after calls") \ \ develop(bool, TraceJavaAssertions, false, \ "Trace java language assertions") \ \ develop(bool, VerifyCodeCache, false, \ "Verify code cache on memory allocation/deallocation") \ \ develop(bool, ZapResourceArea, trueInDebug, \ "Zap freed resource/arena space") \ \ develop(bool, ZapVMHandleArea, trueInDebug, \ "Zap freed VM handle space") \ \ develop(bool, ZapStackSegments, trueInDebug, \ "Zap allocated/freed stack segments") \ \ develop(bool, ZapUnusedHeapArea, trueInDebug, \ "Zap unused heap space") \ \ develop(bool, ZapFillerObjects, trueInDebug, \ "Zap filler objects") \ \ develop(bool, ZapTLAB, trueInDebug, \ "Zap allocated TLABs") \ develop(bool, TestingAsyncLoggingDeathTest, false, \ "Recursive logging death test") \ develop(bool, TestingAsyncLoggingDeathTestNoCrash, false, \ "Recursive logging death test (no crash)") \ \ product(bool, ExecutingUnitTests, false, \ "Whether the JVM is running unit tests or not") \ \ develop(uint, ErrorHandlerTest, 0, \ "If > 0, provokes an error after VM initialization; the value " \ "determines which error to provoke. See controlled_crash() " \ "in vmError.cpp.") \ range(0, 17) \ \ develop(uint, TestCrashInErrorHandler, 0, \ "If > 0, provokes an error inside VM error handler (a secondary " \ "crash). see controlled_crash() in vmError.cpp") \ range(0, 17) \ \ develop(bool, TestSafeFetchInErrorHandler, false , \ "If true, tests SafeFetch inside error handler.") \ \ develop(bool, TestUnresponsiveErrorHandler, false, \ "If true, simulates an unresponsive error handler.") \ \ develop(bool, Verbose, false, \ "Print additional debugging information from other modes") \ \ develop(bool, PrintMiscellaneous, false, \ "Print uncategorized debugging information (requires +Verbose)") \ \ develop(bool, WizardMode, false, \ "Print much more debugging information") \ \ product(bool, ShowMessageBoxOnError, false, \ "Keep process alive on VM fatal error") \ \ product(bool, CreateCoredumpOnCrash, true, \ "Create core/mini dump on VM fatal error") \ \ product(uint64_t, ErrorLogTimeout, 2 * 60, \ "Timeout, in seconds, to limit the time spent on writing an " \ "error log in case of a crash.") \ range(0, (uint64_t)max_jlong/1000) \ \ product(bool, ErrorLogSecondaryErrorDetails, false, DIAGNOSTIC, \ "If enabled, show details on secondary crashes in the error log") \ \ develop(intx, TraceDwarfLevel, 0, \ "Debug levels for the dwarf parser") \ range(0, 4) \ \ product(bool, SuppressFatalErrorMessage, false, \ "Report NO fatal error message (avoid deadlock)") \ \ product(ccstrlist, OnError, "", \ "Run user-defined commands on fatal error; see VMError.cpp " \ "for examples") \ \ product(ccstrlist, OnOutOfMemoryError, "", \ "Run user-defined commands on first java.lang.OutOfMemoryError " \ "thrown from JVM") \ \ product(bool, HeapDumpBeforeFullGC, false, MANAGEABLE, \ "Dump heap to file before any major stop-the-world GC " \ "(also see FullGCHeapDumpLimit, HeapDumpPath, HeapDumpGzipLevel)")\ \ product(bool, HeapDumpAfterFullGC, false, MANAGEABLE, \ "Dump heap to file after any major stop-the-world GC " \ "(also see FullGCHeapDumpLimit, HeapDumpPath, HeapDumpGzipLevel)")\ \ product(uint, FullGCHeapDumpLimit, 0, MANAGEABLE, \ "Limit the number of heap dumps triggered by " \ "HeapDumpBeforeFullGC or HeapDumpAfterFullGC " \ "(0 means no limit)") \ \ product(bool, HeapDumpOnOutOfMemoryError, false, MANAGEABLE, \ "Dump heap to file when java.lang.OutOfMemoryError is thrown " \ "from JVM " \ "(also see HeapDumpPath, HeapDumpGzipLevel)") \ \ product(ccstr, HeapDumpPath, nullptr, MANAGEABLE, \ "When HeapDumpOnOutOfMemoryError, HeapDumpBeforeFullGC " \ "or HeapDumpAfterFullGC is on, the path (filename or " \ "directory) of the dump file (defaults to java_pid.hprof " \ "in the working directory)") \ \ product(int, HeapDumpGzipLevel, 0, MANAGEABLE, \ "When HeapDumpOnOutOfMemoryError, HeapDumpBeforeFullGC " \ "or HeapDumpAfterFullGC is on, the gzip compression " \ "level of the dump file. 0 (the default) disables gzip " \ "compression. Otherwise the level must be between 1 and 9.") \ range(0, 9) \ \ product(ccstr, NativeMemoryTracking, DEBUG_ONLY("summary") NOT_DEBUG("off"), \ "Native memory tracking options") \ \ product(bool, PrintNMTStatistics, false, DIAGNOSTIC, \ "Print native memory tracking summary data if it is on") \ \ product(bool, LogCompilation, false, DIAGNOSTIC, \ "Log compilation activity in detail to LogFile") \ \ product(bool, PrintCompilation, false, \ "Print compilations") \ \ product(intx, RepeatCompilation, 0, DIAGNOSTIC, \ "Repeat compilation without installing code (number of times)") \ range(0, max_jint) \ \ product(bool, PrintExtendedThreadInfo, false, \ "Print more information in thread dump") \ \ product(intx, ScavengeRootsInCode, 2, DIAGNOSTIC, \ "0: do not allow scavengable oops in the code cache; " \ "1: allow scavenging from the code cache; " \ "2: emit as many constants as the compiler can see") \ range(0, 2) \ \ product(bool, AlwaysRestoreFPU, false, \ "Restore the FPU control word after every JNI call (expensive)") \ \ product(bool, PrintCompilation2, false, DIAGNOSTIC, \ "Print additional statistics per compilation") \ \ product(bool, PrintAdapterHandlers, false, DIAGNOSTIC, \ "Print code generated for i2c/c2i adapters") \ \ product(bool, VerifyAdapterCalls, trueInDebug, DIAGNOSTIC, \ "Verify that i2c/c2i adapters are called properly") \ \ develop(bool, VerifyAdapterSharing, false, \ "Verify that the code for shared adapters is the equivalent") \ \ product(bool, PrintAssembly, false, DIAGNOSTIC, \ "Print assembly code (using external disassembler.so)") \ \ product(ccstr, PrintAssemblyOptions, nullptr, DIAGNOSTIC, \ "Print options string passed to disassembler.so") \ \ develop(bool, PrintNMethodStatistics, false, \ "Print a summary statistic for the generated nmethods") \ \ product(bool, PrintNMethods, false, DIAGNOSTIC, \ "Print assembly code for nmethods when generated") \ \ product(bool, PrintNativeNMethods, false, DIAGNOSTIC, \ "Print assembly code for native nmethods when generated") \ \ develop(bool, PrintDebugInfo, false, \ "Print debug information for all nmethods when generated") \ \ develop(bool, PrintRelocations, false, \ "Print relocation information for all nmethods when generated") \ \ develop(bool, PrintDependencies, false, \ "Print dependency information for all nmethods when generated") \ \ develop(bool, PrintExceptionHandlers, false, \ "Print exception handler tables for all nmethods when generated") \ \ develop(bool, StressCompiledExceptionHandlers, false, \ "Exercise compiled exception handlers") \ \ product(bool, DeoptimizeOnAllocationException, false, DIAGNOSTIC, \ "Deoptimize on exception during allocation instead of using the " \ "compiled exception handlers") \ \ develop(bool, InterceptOSException, false, \ "Start debugger when an implicit OS (e.g. null pointer) " \ "exception happens") \ \ product(bool, PrintCodeCache, false, \ "Print the code cache memory usage when exiting") \ \ develop(bool, PrintCodeCache2, false, \ "Print detailed usage information on the code cache when exiting")\ \ product(bool, PrintCodeCacheOnCompilation, false, \ "Print the code cache memory usage each time a method is " \ "compiled") \ \ product(bool, PrintCodeHeapAnalytics, false, DIAGNOSTIC, \ "Print code heap usage statistics on exit and on full condition") \ \ product(bool, PrintStubCode, false, DIAGNOSTIC, \ "Print generated stub code") \ \ product(bool, StackTraceInThrowable, true, \ "Collect backtrace in throwable when exception happens") \ \ product(bool, OmitStackTraceInFastThrow, true, \ "Omit backtraces for some 'hot' exceptions in optimized code") \ \ product(bool, ShowCodeDetailsInExceptionMessages, true, MANAGEABLE, \ "Show exception messages from RuntimeExceptions that contain " \ "snippets of the failing code. Disable this to improve privacy.") \ \ product(bool, PrintWarnings, true, \ "Print JVM warnings to output stream") \ \ develop(bool, RegisterReferences, true, \ "Tell whether the VM should register soft/weak/final/phantom " \ "references") \ \ develop(bool, PrintCodeCacheExtension, false, \ "Print extension of code cache") \ \ product(bool, ClassUnloading, true, \ "Do unloading of classes") \ \ product(bool, ClassUnloadingWithConcurrentMark, true, \ "Do unloading of classes with a concurrent marking cycle") \ \ develop(bool, PrintSystemDictionaryAtExit, false, \ "Print the system dictionary at exit") \ \ develop(bool, PrintClassLoaderDataGraphAtExit, false, \ "Print the class loader data graph at exit") \ \ product(bool, PrintVMInfoAtExit, false, DIAGNOSTIC, \ "Executes the VM.info diagnostic command at exit") \ \ product(bool, AllowParallelDefineClass, false, \ "Allow parallel defineClass requests for class loaders " \ "registering as parallel capable") \ \ product(bool, DisablePrimordialThreadGuardPages, false, EXPERIMENTAL, \ "Disable the use of stack guard pages if the JVM is loaded " \ "on the primordial process thread") \ \ product(bool, DoJVMTIVirtualThreadTransitions, true, EXPERIMENTAL, \ "Do JVMTI virtual thread mount/unmount transitions " \ "(disabling this flag implies no JVMTI events are posted)") \ \ /* notice: the max range value here is max_jint, not max_intx */ \ /* because of overflow issue */ \ product(intx, AsyncDeflationInterval, 250, DIAGNOSTIC, \ "Async deflate idle monitors every so many milliseconds when " \ "MonitorUsedDeflationThreshold is exceeded (0 is off).") \ range(0, max_jint) \ \ /* notice: the max range value here is max_jint, not max_intx */ \ /* because of overflow issue */ \ product(intx, GuaranteedAsyncDeflationInterval, 60000, DIAGNOSTIC, \ "Async deflate idle monitors every so many milliseconds even " \ "when MonitorUsedDeflationThreshold is NOT exceeded (0 is off).") \ range(0, max_jint) \ \ product(size_t, AvgMonitorsPerThreadEstimate, 1024, DIAGNOSTIC, \ "Used to estimate a variable ceiling based on number of threads " \ "for use with MonitorUsedDeflationThreshold (0 is off).") \ range(0, max_uintx) \ \ /* notice: the max range value here is max_jint, not max_intx */ \ /* because of overflow issue */ \ product(intx, MonitorDeflationMax, 1000000, DIAGNOSTIC, \ "The maximum number of monitors to deflate, unlink and delete " \ "at one time (minimum is 1024).") \ range(1024, max_jint) \ \ product(intx, MonitorUnlinkBatch, 500, DIAGNOSTIC, \ "The maximum number of monitors to unlink in one batch. ") \ range(1, max_jint) \ \ product(int, MonitorUsedDeflationThreshold, 90, DIAGNOSTIC, \ "Percentage of used monitors before triggering deflation (0 is " \ "off). The check is performed on AsyncDeflationInterval or " \ "GuaranteedAsyncDeflationInterval, whichever is lower.") \ range(0, 100) \ \ product(uintx, NoAsyncDeflationProgressMax, 3, DIAGNOSTIC, \ "Max number of no progress async deflation attempts to tolerate " \ "before adjusting the in_use_list_ceiling up (0 is off).") \ range(0, max_uintx) \ \ product(intx, hashCode, 5, EXPERIMENTAL, \ "(Unstable) select hashCode generation algorithm") \ \ product(bool, ReduceSignalUsage, false, \ "Reduce the use of OS signals in Java and/or the VM") \ \ develop(bool, LoadLineNumberTables, true, \ "Tell whether the class file parser loads line number tables") \ \ develop(bool, LoadLocalVariableTables, true, \ "Tell whether the class file parser loads local variable tables") \ \ develop(bool, LoadLocalVariableTypeTables, true, \ "Tell whether the class file parser loads local variable type" \ "tables") \ \ product(bool, AllowUserSignalHandlers, false, \ "Application will install primary signal handlers for the JVM " \ "(Unix only)") \ \ product(bool, UseSignalChaining, true, \ "Use signal-chaining to invoke signal handlers installed " \ "by the application (Unix only)") \ \ product(bool, RestoreMXCSROnJNICalls, false, \ "Restore MXCSR when returning from JNI calls") \ \ product(bool, CheckJNICalls, false, \ "Verify all arguments to JNI calls") \ \ product(bool, UseFastJNIAccessors, true, \ "Use optimized versions of GetField") \ \ product(intx, MaxJNILocalCapacity, 65536, \ "Maximum allowable local JNI handle capacity to " \ "EnsureLocalCapacity() and PushLocalFrame(), " \ "where <= 0 is unlimited, default: 65536") \ range(min_intx, max_intx) \ \ product(bool, EagerXrunInit, false, \ "Eagerly initialize -Xrun libraries; allows startup profiling, " \ "but not all -Xrun libraries may support the state of the VM " \ "at this time") \ \ develop(uintx, PreallocatedOutOfMemoryErrorCount, 4, \ "Number of OutOfMemoryErrors preallocated with backtrace") \ \ product(bool, UseXMMForArrayCopy, false, \ "Use SSE2 MOVQ instruction for Arraycopy") \ \ develop(bool, PrintFieldLayout, false, \ "Print field layout for each class") \ \ /* Need to limit the extent of the padding to reasonable size. */\ /* 8K is well beyond the reasonable HW cache line size, even with */\ /* aggressive prefetching, while still leaving the room for segregating */\ /* among the distinct pages. */\ product(int, ContendedPaddingWidth, 128, \ "How many bytes to pad the fields/classes marked @Contended with")\ range(0, 8192) \ constraint(ContendedPaddingWidthConstraintFunc,AfterErgo) \ \ product(bool, EnableContended, true, \ "Enable @Contended annotation support") \ \ product(bool, RestrictContended, true, \ "Restrict @Contended to trusted classes") \ \ product(int, DiagnoseSyncOnValueBasedClasses, 0, DIAGNOSTIC, \ "Detect and take action upon identifying synchronization on " \ "value based classes. Modes: " \ "0: off; " \ "1: exit with fatal error; " \ "2: log message to stdout. Output file can be specified with " \ " -Xlog:valuebasedclasses. If JFR is running it will " \ " also generate JFR events.") \ range(0, 2) \ \ product(bool, ExitOnOutOfMemoryError, false, \ "JVM exits on the first occurrence of an out-of-memory error " \ "thrown from JVM") \ \ product(bool, CrashOnOutOfMemoryError, false, \ "JVM aborts, producing an error log and core/mini dump, on the " \ "first occurrence of an out-of-memory error thrown from JVM") \ \ product(intx, UserThreadWaitAttemptsAtExit, 30, \ "The number of times to wait for user threads to stop executing " \ "native code during JVM exit. Each wait lasts 10 milliseconds. " \ "The maximum number of waits is 1000, to wait at most 10 " \ "seconds.") \ range(0, 1000) \ \ /* tracing */ \ \ develop(bool, StressRewriter, false, \ "Stress linktime bytecode rewriting") \ \ product(ccstr, TraceJVMTI, nullptr, \ "Trace flags for JVMTI functions and events") \ \ product(bool, StressLdcRewrite, false, DIAGNOSTIC, \ "Force ldc -> ldc_w rewrite during RedefineClasses. " \ "This option can change an EMCP method into an obsolete method " \ "and can affect tests that expect specific methods to be EMCP. " \ "This option should be used with caution.") \ \ product(bool, AllowRedefinitionToAddDeleteMethods, false, \ "(Deprecated) Allow redefinition to add and delete private " \ "static or final methods for compatibility with old releases") \ \ develop(bool, TraceBytecodes, false, \ "Trace bytecode execution") \ \ develop(bool, TraceBytecodesTruncated, false, \ "Truncate non control-flow bytecode when tracing bytecode") \ \ develop(bool, VerifyDependencies, trueInDebug, \ "Exercise and verify the compilation dependency mechanism") \ \ develop(bool, TraceNewOopMapGeneration, false, \ "Trace OopMapGeneration") \ \ develop(bool, TraceNewOopMapGenerationDetailed, false, \ "Trace OopMapGeneration: print detailed cell states") \ \ develop(bool, TimeOopMap, false, \ "Time calls to GenerateOopMap::compute_map() in sum") \ \ develop(bool, TimeOopMap2, false, \ "Time calls to GenerateOopMap::compute_map() individually") \ \ develop(bool, TraceOopMapRewrites, false, \ "Trace rewriting of methods during oop map generation") \ \ develop(bool, TraceFinalizerRegistration, false, \ "Trace registration of final references") \ \ product(bool, IgnoreEmptyClassPaths, false, \ "Ignore empty path elements in -classpath") \ \ product(bool, PrintHeapAtSIGBREAK, true, \ "Print heap layout in response to SIGBREAK") \ \ product(bool, PrintClassHistogram, false, MANAGEABLE, \ "Print a histogram of class instances") \ \ product(double, ObjectCountCutOffPercent, 0.5, EXPERIMENTAL, \ "The percentage of the used heap that the instances of a class " \ "must occupy for the class to generate a trace event") \ range(0.0, 100.0) \ \ /* JVMTI heap profiling */ \ \ product(bool, VerifyBeforeIteration, false, DIAGNOSTIC, \ "Verify memory system before JVMTI iteration") \ \ /* compiler */ \ \ /* notice: the max range value here is max_jint, not max_intx */ \ /* because of overflow issue */ \ product(intx, CICompilerCount, CI_COMPILER_COUNT, \ "Number of compiler threads to run") \ range(0, max_jint) \ constraint(CICompilerCountConstraintFunc, AfterErgo) \ \ product(bool, UseDynamicNumberOfCompilerThreads, true, \ "Dynamically choose the number of parallel compiler threads") \ \ product(bool, ReduceNumberOfCompilerThreads, true, DIAGNOSTIC, \ "Reduce the number of parallel compiler threads when they " \ "are not used") \ \ product(bool, TraceCompilerThreads, false, DIAGNOSTIC, \ "Trace creation and removal of compiler threads") \ \ product(ccstr, LogClassLoadingCauseFor, nullptr, \ "Apply -Xlog:class+load+cause* to classes whose fully " \ "qualified name contains this string (\"*\" matches " \ "any class).") \ \ develop(bool, InjectCompilerCreationFailure, false, \ "Inject thread creation failures for " \ "UseDynamicNumberOfCompilerThreads") \ \ develop(bool, GenerateSynchronizationCode, true, \ "generate locking/unlocking code for synchronized methods and " \ "monitors") \ \ product_pd(bool, ImplicitNullChecks, DIAGNOSTIC, \ "Generate code for implicit null checks") \ \ product_pd(bool, TrapBasedNullChecks, \ "Generate code for null checks that uses a cmp and trap " \ "instruction raising SIGTRAP. This is only used if an access to" \ "null (+offset) will not raise a SIGSEGV, i.e.," \ "ImplicitNullChecks don't work (PPC64).") \ \ product(bool, EnableThreadSMRStatistics, trueInDebug, DIAGNOSTIC, \ "Enable Thread SMR Statistics") \ \ product(bool, Inline, true, \ "Enable inlining") \ \ product(bool, ClipInlining, true, \ "Clip inlining if aggregate method exceeds DesiredMethodLimit") \ \ develop(bool, UseCHA, true, \ "Enable CHA") \ \ product(bool, UseTypeProfile, true, \ "Check interpreter profile for historically monomorphic calls") \ \ product(bool, PrintInlining, false, DIAGNOSTIC, \ "Print inlining optimizations") \ \ product(bool, UsePopCountInstruction, false, \ "Use population count instruction") \ \ develop(bool, TraceMethodReplacement, false, \ "Print when methods are replaced do to recompilation") \ \ product(intx, MinPassesBeforeFlush, 10, DIAGNOSTIC, \ "Minimum number of sweeper passes before an nmethod " \ "can be flushed") \ range(0, max_intx) \ \ develop(bool, StressCodeBuffers, false, \ "Exercise code buffer expansion and other rare state changes") \ \ product(bool, DebugNonSafepoints, trueInDebug, DIAGNOSTIC, \ "Generate extra debugging information for non-safepoints in " \ "nmethods") \ \ product(bool, PrintVMOptions, false, \ "Print flags that appeared on the command line") \ \ product(bool, IgnoreUnrecognizedVMOptions, false, \ "Ignore unrecognized VM options") \ \ product(bool, PrintCommandLineFlags, false, \ "Print flags specified on command line or set by ergonomics") \ \ product(bool, PrintFlagsInitial, false, \ "Print all VM flags before argument processing and exit VM") \ \ product(bool, PrintFlagsFinal, false, \ "Print all VM flags after argument and ergonomic processing") \ \ develop(bool, PrintFlagsWithComments, false, \ "Print all VM flags with default values and descriptions and " \ "exit") \ \ product(bool, PrintFlagsRanges, false, \ "Print VM flags and their ranges") \ \ product(bool, SerializeVMOutput, true, DIAGNOSTIC, \ "Use a mutex to serialize output to tty and LogFile") \ \ product(bool, DisplayVMOutput, true, DIAGNOSTIC, \ "Display all VM output on the tty, independently of LogVMOutput") \ \ product(bool, LogVMOutput, false, DIAGNOSTIC, \ "Save VM output to LogFile") \ \ product(ccstr, LogFile, nullptr, DIAGNOSTIC, \ "If LogVMOutput or LogCompilation is on, save VM output to " \ "this file [default: ./hotspot_pid%p.log] (%p replaced with pid)")\ \ product(ccstr, ErrorFile, nullptr, \ "If an error occurs, save the error data to this file " \ "[default: ./hs_err_pid%p.log] (%p replaced with pid)") \ \ product(bool, ExtensiveErrorReports, \ PRODUCT_ONLY(false) NOT_PRODUCT(true), \ "Error reports are more extensive.") \ \ product(bool, DisplayVMOutputToStderr, false, \ "If DisplayVMOutput is true, display all VM output to stderr") \ \ product(bool, DisplayVMOutputToStdout, false, \ "If DisplayVMOutput is true, display all VM output to stdout") \ \ product(bool, ErrorFileToStderr, false, \ "If true, error data is printed to stderr instead of a file") \ \ product(bool, ErrorFileToStdout, false, \ "If true, error data is printed to stdout instead of a file") \ \ develop(bool, VerifyHeavyMonitors, false, \ "Checks that no stack locking happens when using " \ "-XX:LockingMode=0 (LM_MONITOR)") \ \ product(bool, PrintStringTableStatistics, false, \ "print statistics about the StringTable and SymbolTable") \ \ product(bool, VerifyStringTableAtExit, false, DIAGNOSTIC, \ "verify StringTable contents at exit") \ \ develop(bool, PrintSymbolTableSizeHistogram, false, \ "print histogram of the symbol table") \ \ product(ccstr, AbortVMOnException, nullptr, DIAGNOSTIC, \ "Call fatal if this exception is thrown. Example: " \ "java -XX:AbortVMOnException=java.lang.NullPointerException Foo") \ \ product(ccstr, AbortVMOnExceptionMessage, nullptr, DIAGNOSTIC, \ "Call fatal if the exception pointed by AbortVMOnException " \ "has this message") \ \ develop(bool, DebugVtables, false, \ "add debugging code to vtable dispatch") \ \ product(bool, RangeCheckElimination, true, \ "Eliminate range checks") \ \ develop_pd(bool, UncommonNullCast, \ "track occurrences of null in casts; adjust compiler tactics") \ \ develop(bool, TypeProfileCasts, true, \ "treat casts like calls for purposes of type profiling") \ \ develop(bool, TraceLivenessGen, false, \ "Trace the generation of liveness analysis information") \ \ develop(bool, TraceLivenessQuery, false, \ "Trace queries of liveness analysis information") \ \ develop(bool, CollectIndexSetStatistics, false, \ "Collect information about IndexSets") \ \ /* This value is later shifted left by up to LogBytesPerLong bits */\ /* (to convert from element count to size in bytes), so we must ensure */\ /* it does not overflow during the shift. */\ develop(int, FastAllocateSizeLimit, 128*K, \ /* Note: This value is zero mod 1<<13 for a cheap sparc set. */ \ "Inline allocations larger than this in doublewords must go slow")\ range(0, (1 << (BitsPerInt - LogBytesPerLong - 1)) - 1) \ \ product_pd(bool, CompactStrings, \ "Enable Strings to use single byte chars in backing store") \ \ product_pd(uint, TypeProfileLevel, \ "=XYZ, with Z: Type profiling of arguments at call; " \ "Y: Type profiling of return value at call; " \ "X: Type profiling of parameters to methods; " \ "X, Y and Z in 0=off ; 1=jsr292 only; 2=all methods") \ constraint(TypeProfileLevelConstraintFunc, AfterErgo) \ \ product(int, TypeProfileArgsLimit, 2, \ "max number of call arguments to consider for type profiling") \ range(0, 16) \ \ product(int, TypeProfileParmsLimit, 2, \ "max number of incoming parameters to consider for type profiling"\ ", -1 for all") \ range(-1, 64) \ \ /* statistics */ \ develop(bool, CountCompiledCalls, false, \ "Count method invocations") \ \ develop(bool, ICMissHistogram, false, \ "Produce histogram of IC misses") \ \ /* interpreter */ \ product_pd(bool, RewriteBytecodes, \ "Allow rewriting of bytecodes (bytecodes are not immutable)") \ \ product_pd(bool, RewriteFrequentPairs, \ "Rewrite frequently used bytecode pairs into a single bytecode") \ \ product(bool, PrintInterpreter, false, DIAGNOSTIC, \ "Print the generated interpreter code") \ \ product(bool, UseInterpreter, true, \ "Use interpreter for non-compiled methods") \ \ develop(bool, UseFastSignatureHandlers, true, \ "Use fast signature handlers for native calls") \ \ product(bool, UseLoopCounter, true, \ "Increment invocation counter on backward branch") \ \ product_pd(bool, UseOnStackReplacement, \ "Use on stack replacement, calls runtime if invoc. counter " \ "overflows in loop") \ \ develop(bool, TraceOnStackReplacement, false, \ "Trace on stack replacement") \ \ product_pd(bool, PreferInterpreterNativeStubs, \ "Use always interpreter stubs for native methods invoked via " \ "interpreter") \ \ develop(bool, CountBytecodes, false, \ "Count number of bytecodes executed") \ \ develop(bool, PrintBytecodeHistogram, false, \ "Print histogram of the executed bytecodes") \ \ develop(bool, PrintBytecodePairHistogram, false, \ "Print histogram of the executed bytecode pairs") \ \ product(bool, PrintSignatureHandlers, false, DIAGNOSTIC, \ "Print code generated for native method signature handlers") \ \ develop(bool, VerifyOops, false, \ "Do plausibility checks for oops") \ \ develop(bool, CheckUnhandledOops, false, \ "Check for unhandled oops in VM code") \ \ develop(bool, VerifyJNIFields, trueInDebug, \ "Verify jfieldIDs for instance fields") \ \ develop(bool, VerifyActivationFrameSize, false, \ "Verify that activation frame didn't become smaller than its " \ "minimal size") \ \ develop(bool, TraceFrequencyInlining, false, \ "Trace frequency based inlining") \ \ develop_pd(bool, InlineIntrinsics, \ "Use intrinsics in Interpreter that can be statically resolved") \ \ product_pd(bool, ProfileInterpreter, \ "Profile at the bytecode level during interpretation") \ \ develop_pd(bool, ProfileTraps, \ "Profile deoptimization traps at the bytecode level") \ \ product(intx, ProfileMaturityPercentage, 20, \ "number of method invocations/branches (expressed as % of " \ "CompileThreshold) before using the method's profile") \ range(0, 100) \ \ product(bool, PrintMethodData, false, DIAGNOSTIC, \ "Print the results of +ProfileInterpreter at end of run") \ \ develop(bool, VerifyDataPointer, trueInDebug, \ "Verify the method data pointer during interpreter profiling") \ \ develop(bool, CrashGCForDumpingJavaThread, false, \ "Manually make GC thread crash then dump java stack trace; " \ "Test only") \ \ /* compilation */ \ product(bool, UseCompiler, true, \ "Use Just-In-Time compilation") \ \ product(bool, AlwaysCompileLoopMethods, false, \ "When using recompilation, never interpret methods " \ "containing loops") \ \ product(int, AllocatePrefetchStyle, 1, \ "0 = no prefetch, " \ "1 = generate prefetch instructions for each allocation, " \ "2 = use TLAB watermark to gate allocation prefetch, " \ "3 = generate one prefetch instruction per cache line") \ range(0, 3) \ \ product(int, AllocatePrefetchDistance, -1, \ "Distance to prefetch ahead of allocation pointer. " \ "-1: use system-specific value (automatically determined") \ range(-1, 512) \ \ product(int, AllocatePrefetchLines, 3, \ "Number of lines to prefetch ahead of array allocation pointer") \ range(1, 64) \ \ product(int, AllocateInstancePrefetchLines, 1, \ "Number of lines to prefetch ahead of instance allocation " \ "pointer") \ range(1, 64) \ \ product(int, AllocatePrefetchStepSize, 16, \ "Step size in bytes of sequential prefetch instructions") \ range(1, 512) \ constraint(AllocatePrefetchStepSizeConstraintFunc,AfterMemoryInit)\ \ product(intx, AllocatePrefetchInstr, 0, \ "Select instruction to prefetch ahead of allocation pointer") \ constraint(AllocatePrefetchInstrConstraintFunc, AfterMemoryInit) \ \ /* deoptimization */ \ product(bool, TraceDeoptimization, false, DIAGNOSTIC, \ "Trace deoptimization") \ \ develop(bool, PrintDeoptimizationDetails, false, \ "Print more information about deoptimization") \ \ develop(bool, DebugDeoptimization, false, \ "Tracing various information while debugging deoptimization") \ \ product(double, SelfDestructTimer, 0.0, \ "Will cause VM to terminate after a given time " \ "(in fractional minutes) " \ "(0.0 means off)") \ range(0.0, (double)max_intx) \ \ product(int, MaxJavaStackTraceDepth, 1024, \ "The maximum number of lines in the stack trace for Java " \ "exceptions (0 means all)") \ range(0, max_jint/2) \ \ /* notice: the max range value here is max_jint, not max_intx */ \ /* because of overflow issue */ \ product(intx, GuaranteedSafepointInterval, 0, DIAGNOSTIC, \ "Guarantee a safepoint (at least) every so many milliseconds " \ "(0 means none)") \ range(0, max_jint) \ \ product(intx, ServiceThreadCleanupInterval, 1000, DIAGNOSTIC, \ "Wake the ServiceThread to do periodic cleanup checks every so " \ "many milliseconds (0 means none)") \ range(0, max_jint) \ \ product(double, SafepointTimeoutDelay, 10000, \ "Delay in milliseconds for option SafepointTimeout; " \ "supports sub-millisecond resolution with fractional values.") \ range(0, max_jlongDouble LP64_ONLY(/MICROUNITS)) \ \ product(bool, UseSystemMemoryBarrier, false, \ "Try to enable system memory barrier if supported by OS") \ \ product(intx, NmethodSweepActivity, 4, \ "Removes cold nmethods from code cache if > 0. Higher values " \ "result in more aggressive sweeping") \ range(0, 2000) \ \ develop(intx, MallocCatchPtr, -1, \ "Hit breakpoint when mallocing/freeing this pointer") \ \ develop(int, StackPrintLimit, 100, \ "number of stack frames to print in VM-level stack dump") \ \ product(int, ErrorLogPrintCodeLimit, 3, DIAGNOSTIC, \ "max number of compiled code units to print in error log") \ range(0, VMError::max_error_log_print_code) \ \ develop(int, MaxElementPrintSize, 256, \ "maximum number of elements to print") \ \ develop(int, MaxStringPrintSize, 256, \ "maximum number of characters to print for a java.lang.String " \ "in the VM. If exceeded, an abridged version of the string is " \ "printed with the middle of the string elided.") \ range(2, O_BUFLEN) \ \ develop(intx, MaxSubklassPrintSize, 4, \ "maximum number of subklasses to print when printing klass") \ \ develop(intx, MaxForceInlineLevel, 100, \ "maximum number of nested calls that are forced for inlining " \ "(using CompileCommand or marked w/ @ForceInline)") \ range(0, max_jint) \ \ develop(intx, MethodHistogramCutoff, 100, \ "The cutoff value for method invocation histogram (+CountCalls)") \ \ develop(intx, DeoptimizeALotInterval, 5, \ "Number of exits until DeoptimizeALot kicks in") \ \ develop(intx, ZombieALotInterval, 5, \ "Number of exits until ZombieALot kicks in") \ \ product(ccstr, MallocLimit, nullptr, DIAGNOSTIC, \ "Limit malloc allocation size from VM. Reaching a limit will " \ "trigger an action (see flag). This feature requires " \ "NativeMemoryTracking=summary or NativeMemoryTracking=detail." \ "Usage:" \ "\"-XX:MallocLimit=[:]\" sets a total limit." \ "\"-XX:MallocLimit=:[:][,:[:] ...]\"" \ "sets one or more category-specific limits." \ " defines the action upon reaching the limit:" \ "\"fatal\": end VM with a fatal error at the allocation site" \ "\"oom\" : will mimic a native OOM" \ "If is omitted, \"fatal\" is the default." \ "Examples:\n" \ "-XX:MallocLimit=2g" \ "-XX:MallocLimit=2g:oom" \ "-XX:MallocLimit=compiler:200m:oom,code:100m") \ \ product(intx, TypeProfileWidth, 2, \ "Number of receiver types to record in call/cast profile") \ range(0, 8) \ \ develop(intx, BciProfileWidth, 2, \ "Number of return bci's to record in ret profile") \ \ product(intx, PerMethodRecompilationCutoff, 400, \ "After recompiling N times, stay in the interpreter (-1=>'Inf')") \ range(-1, max_intx) \ \ product(intx, PerBytecodeRecompilationCutoff, 200, \ "Per-BCI limit on repeated recompilation (-1=>'Inf')") \ range(-1, max_intx) \ \ product(intx, PerMethodTrapLimit, 100, \ "Limit on traps (of one kind) in a method (includes inlines)") \ range(0, max_jint) \ \ product(intx, PerMethodSpecTrapLimit, 5000, EXPERIMENTAL, \ "Limit on speculative traps (of one kind) in a method " \ "(includes inlines)") \ range(0, max_jint) \ \ product(intx, PerBytecodeTrapLimit, 4, \ "Limit on traps (of one kind) at a particular BCI") \ range(0, max_jint) \ \ product(int, SpecTrapLimitExtraEntries, 3, EXPERIMENTAL, \ "Extra method data trap entries for speculation") \ \ product(double, InlineFrequencyRatio, 0.25, DIAGNOSTIC, \ "Ratio of call site execution to caller method invocation") \ \ product(double, MinInlineFrequencyRatio, 0.0085, DIAGNOSTIC, \ "Minimum ratio of call site execution to caller method" \ "invocation to be considered for inlining") \ \ develop(intx, InlineThrowCount, 50, \ "Force inlining of interpreted methods that throw this often") \ range(0, max_jint) \ \ develop(intx, InlineThrowMaxSize, 200, \ "Force inlining of throwing methods smaller than this") \ range(0, max_jint) \ \ product(size_t, MetaspaceSize, NOT_LP64(16 * M) LP64_ONLY(21 * M), \ "Initial threshold (in bytes) at which a garbage collection " \ "is done to reduce Metaspace usage") \ constraint(MetaspaceSizeConstraintFunc,AfterErgo) \ \ product(size_t, MaxMetaspaceSize, max_uintx, \ "Maximum size of Metaspaces (in bytes)") \ constraint(MaxMetaspaceSizeConstraintFunc,AfterErgo) \ \ product(size_t, CompressedClassSpaceSize, 1*G, \ "Maximum size of class area in Metaspace when compressed " \ "class pointers are used") \ range(1*M, LP64_ONLY(4*G) NOT_LP64(max_uintx)) \ \ develop(size_t, CompressedClassSpaceBaseAddress, 0, \ "Force the class space to be allocated at this address or " \ "fails VM initialization (requires -Xshare=off.") \ \ develop(bool, RandomizeClassSpaceLocation, true, \ "Randomize location of class space.") \ \ product(bool, PrintMetaspaceStatisticsAtExit, false, DIAGNOSTIC, \ "Print metaspace statistics upon VM exit.") \ \ product(bool, PrintCompilerMemoryStatisticsAtExit, false, DIAGNOSTIC, \ "Print compiler memory statistics upon VM exit.") \ \ product(uintx, MinHeapFreeRatio, 40, MANAGEABLE, \ "The minimum percentage of heap free after GC to avoid expansion."\ " For most GCs this applies to the old generation. In G1 and" \ " ParallelGC it applies to the whole heap.") \ range(0, 100) \ constraint(MinHeapFreeRatioConstraintFunc,AfterErgo) \ \ product(uintx, MaxHeapFreeRatio, 70, MANAGEABLE, \ "The maximum percentage of heap free after GC to avoid shrinking."\ " For most GCs this applies to the old generation. In G1 and" \ " ParallelGC it applies to the whole heap.") \ range(0, 100) \ constraint(MaxHeapFreeRatioConstraintFunc,AfterErgo) \ \ product(intx, SoftRefLRUPolicyMSPerMB, 1000, \ "Number of milliseconds per MB of free space in the heap") \ range(0, max_intx) \ constraint(SoftRefLRUPolicyMSPerMBConstraintFunc,AfterMemoryInit) \ \ product(size_t, MinHeapDeltaBytes, ScaleForWordSize(128*K), \ "The minimum change in heap space due to GC (in bytes)") \ range(0, max_uintx / 2 + 1) \ \ product(size_t, MinMetaspaceExpansion, ScaleForWordSize(256*K), \ "The minimum expansion of Metaspace (in bytes)") \ range(0, max_uintx) \ \ product(uint, MaxMetaspaceFreeRatio, 70, \ "The maximum percentage of Metaspace free after GC to avoid " \ "shrinking") \ range(0, 100) \ constraint(MaxMetaspaceFreeRatioConstraintFunc,AfterErgo) \ \ product(uint, MinMetaspaceFreeRatio, 40, \ "The minimum percentage of Metaspace free after GC to avoid " \ "expansion") \ range(0, 99) \ constraint(MinMetaspaceFreeRatioConstraintFunc,AfterErgo) \ \ product(size_t, MaxMetaspaceExpansion, ScaleForWordSize(4*M), \ "The maximum expansion of Metaspace without full GC (in bytes)") \ range(0, max_uintx) \ \ /* stack parameters */ \ product_pd(intx, StackYellowPages, \ "Number of yellow zone (recoverable overflows) pages of size " \ "4KB. If pages are bigger yellow zone is aligned up.") \ range(MIN_STACK_YELLOW_PAGES, (DEFAULT_STACK_YELLOW_PAGES+5)) \ \ product_pd(intx, StackRedPages, \ "Number of red zone (unrecoverable overflows) pages of size " \ "4KB. If pages are bigger red zone is aligned up.") \ range(MIN_STACK_RED_PAGES, (DEFAULT_STACK_RED_PAGES+2)) \ \ product_pd(intx, StackReservedPages, \ "Number of reserved zone (reserved to annotated methods) pages" \ " of size 4KB. If pages are bigger reserved zone is aligned up.") \ range(MIN_STACK_RESERVED_PAGES, (DEFAULT_STACK_RESERVED_PAGES+10))\ \ product(bool, RestrictReservedStack, true, \ "Restrict @ReservedStackAccess to trusted classes") \ \ /* greater stack shadow pages can't generate instruction to bang stack */ \ product_pd(intx, StackShadowPages, \ "Number of shadow zone (for overflow checking) pages of size " \ "4KB. If pages are bigger shadow zone is aligned up. " \ "This should exceed the depth of the VM and native call stack.") \ range(MIN_STACK_SHADOW_PAGES, (DEFAULT_STACK_SHADOW_PAGES+30)) \ \ product_pd(intx, ThreadStackSize, \ "Thread Stack Size (in Kbytes)") \ range(0, 1 * M) \ \ product_pd(intx, VMThreadStackSize, \ "Non-Java Thread Stack Size (in Kbytes)") \ range(0, max_intx/(1 * K)) \ \ product_pd(intx, CompilerThreadStackSize, \ "Compiler Thread Stack Size (in Kbytes)") \ range(0, max_intx/(1 * K)) \ \ develop_pd(size_t, JVMInvokeMethodSlack, \ "Stack space (bytes) required for JVM_InvokeMethod to complete") \ \ /* code cache parameters */ \ product_pd(size_t, CodeCacheSegmentSize, EXPERIMENTAL, \ "Code cache segment size (in bytes) - smallest unit of " \ "allocation") \ range(1, 1024) \ constraint(CodeCacheSegmentSizeConstraintFunc, AfterErgo) \ \ product_pd(intx, CodeEntryAlignment, EXPERIMENTAL, \ "Code entry alignment for generated code (in bytes)") \ constraint(CodeEntryAlignmentConstraintFunc, AfterErgo) \ \ product_pd(intx, OptoLoopAlignment, \ "Align inner loops to zero relative to this modulus") \ range(1, 128) \ constraint(OptoLoopAlignmentConstraintFunc, AfterErgo) \ \ product_pd(size_t, InitialCodeCacheSize, \ "Initial code cache size (in bytes)") \ constraint(VMPageSizeConstraintFunc, AtParse) \ \ develop_pd(size_t, CodeCacheMinimumUseSpace, \ "Minimum code cache size (in bytes) required to start VM.") \ range(0, SIZE_MAX) \ \ product(bool, SegmentedCodeCache, false, \ "Use a segmented code cache") \ \ product_pd(size_t, ReservedCodeCacheSize, \ "Reserved code cache size (in bytes) - maximum code cache size") \ constraint(VMPageSizeConstraintFunc, AtParse) \ \ product_pd(size_t, NonProfiledCodeHeapSize, \ "Size of code heap with non-profiled methods (in bytes)") \ range(0, SIZE_MAX) \ \ product_pd(size_t, ProfiledCodeHeapSize, \ "Size of code heap with profiled methods (in bytes)") \ range(0, SIZE_MAX) \ \ product_pd(size_t, NonNMethodCodeHeapSize, \ "Size of code heap with non-nmethods (in bytes)") \ constraint(VMPageSizeConstraintFunc, AtParse) \ \ product_pd(size_t, CodeCacheExpansionSize, \ "Code cache expansion size (in bytes)") \ range(32*K, SIZE_MAX) \ \ product_pd(size_t, CodeCacheMinBlockLength, DIAGNOSTIC, \ "Minimum number of segments in a code cache block") \ range(1, 100) \ \ develop(bool, ExitOnFullCodeCache, false, \ "Exit the VM if we fill the code cache") \ \ product(bool, UseCodeCacheFlushing, true, \ "Remove cold/old nmethods from the code cache") \ \ product(double, SweeperThreshold, 15.0, \ "Threshold when a code cache unloading GC is invoked." \ "Value is percentage of ReservedCodeCacheSize.") \ range(0.0, 100.0) \ \ product(uintx, StartAggressiveSweepingAt, 10, \ "Start aggressive sweeping if X[%] of the code cache is free." \ "Segmented code cache: X[%] of the non-profiled heap." \ "Non-segmented code cache: X[%] of the total code cache") \ range(0, 100) \ \ /* interpreter debugging */ \ develop(intx, BinarySwitchThreshold, 5, \ "Minimal number of lookupswitch entries for rewriting to binary " \ "switch") \ \ develop(uintx, StopInterpreterAt, 0, \ "Stop interpreter execution at specified bytecode number") \ \ develop(uintx, TraceBytecodesAt, 0, \ "Trace bytecodes starting with specified bytecode number") \ \ develop(uintx, TraceBytecodesStopAt, 0, \ "Stop bytecode tracing at the specified bytecode number") \ \ /* Priorities */ \ product_pd(bool, UseThreadPriorities, "Use native thread priorities") \ \ product(int, ThreadPriorityPolicy, 0, \ "0 : Normal. "\ " VM chooses priorities that are appropriate for normal "\ " applications. "\ " On Windows applications are allowed to use higher native "\ " priorities. However, with ThreadPriorityPolicy=0, VM will "\ " not use the highest possible native priority, "\ " THREAD_PRIORITY_TIME_CRITICAL, as it may interfere with "\ " system threads. On Linux thread priorities are ignored "\ " because the OS does not support static priority in "\ " SCHED_OTHER scheduling class which is the only choice for "\ " non-root, non-realtime applications. "\ "1 : Aggressive. "\ " Java thread priorities map over to the entire range of "\ " native thread priorities. Higher Java thread priorities map "\ " to higher native thread priorities. This policy should be "\ " used with care, as sometimes it can cause performance "\ " degradation in the application and/or the entire system. On "\ " Linux/BSD/macOS this policy requires root privilege or an "\ " extended capability.") \ range(0, 1) \ \ product(bool, ThreadPriorityVerbose, false, \ "Print priority changes") \ \ product(int, CompilerThreadPriority, -1, \ "The native priority at which compiler threads should run " \ "(-1 means no change)") \ range(min_jint, max_jint) \ \ product(int, VMThreadPriority, -1, \ "The native priority at which the VM thread should run " \ "(-1 means no change)") \ range(min_jint, max_jint) \ \ product(int, JavaPriority1_To_OSPriority, -1, \ "Map Java priorities to OS priorities") \ range(min_jint, max_jint) \ \ product(int, JavaPriority2_To_OSPriority, -1, \ "Map Java priorities to OS priorities") \ range(min_jint, max_jint) \ \ product(int, JavaPriority3_To_OSPriority, -1, \ "Map Java priorities to OS priorities") \ range(min_jint, max_jint) \ \ product(int, JavaPriority4_To_OSPriority, -1, \ "Map Java priorities to OS priorities") \ range(min_jint, max_jint) \ \ product(int, JavaPriority5_To_OSPriority, -1, \ "Map Java priorities to OS priorities") \ range(min_jint, max_jint) \ \ product(int, JavaPriority6_To_OSPriority, -1, \ "Map Java priorities to OS priorities") \ range(min_jint, max_jint) \ \ product(int, JavaPriority7_To_OSPriority, -1, \ "Map Java priorities to OS priorities") \ range(min_jint, max_jint) \ \ product(int, JavaPriority8_To_OSPriority, -1, \ "Map Java priorities to OS priorities") \ range(min_jint, max_jint) \ \ product(int, JavaPriority9_To_OSPriority, -1, \ "Map Java priorities to OS priorities") \ range(min_jint, max_jint) \ \ product(int, JavaPriority10_To_OSPriority,-1, \ "Map Java priorities to OS priorities") \ range(min_jint, max_jint) \ \ product(bool, UseCriticalJavaThreadPriority, false, EXPERIMENTAL, \ "Java thread priority 10 maps to critical scheduling priority") \ \ product(bool, UseCriticalCompilerThreadPriority, false, EXPERIMENTAL, \ "Compiler thread(s) run at critical scheduling priority") \ \ develop(intx, NewCodeParameter, 0, \ "Testing Only: Create a dedicated integer parameter before " \ "putback") \ \ /* new oopmap storage allocation */ \ develop(intx, MinOopMapAllocation, 8, \ "Minimum number of OopMap entries in an OopMapSet") \ \ /* recompilation */ \ product_pd(intx, CompileThreshold, \ "number of interpreted method invocations before (re-)compiling") \ constraint(CompileThresholdConstraintFunc, AfterErgo) \ \ product_pd(bool, TieredCompilation, \ "Enable tiered compilation") \ \ /* Properties for Java libraries */ \ \ product(uint64_t, MaxDirectMemorySize, 0, \ "Maximum total size of NIO direct-buffer allocations. " \ "Ignored if not explicitly set.") \ range(0, max_jlong) \ \ /* Flags used for temporary code during development */ \ \ product(bool, UseNewCode, false, DIAGNOSTIC, \ "Testing Only: Use the new version while testing") \ \ product(bool, UseNewCode2, false, DIAGNOSTIC, \ "Testing Only: Use the new version while testing") \ \ product(bool, UseNewCode3, false, DIAGNOSTIC, \ "Testing Only: Use the new version while testing") \ \ develop(bool, UseDebuggerErgo, false, \ "Debugging Only: Adjust the VM to be more debugger-friendly. " \ "Turns on the other UseDebuggerErgo* flags") \ \ develop(bool, UseDebuggerErgo1, false, \ "Debugging Only: Enable workarounds for debugger induced " \ "os::processor_id() >= os::processor_count() problems") \ \ develop(bool, UseDebuggerErgo2, false, \ "Debugging Only: Limit the number of spawned JVM threads") \ \ develop(bool, EnableJVMTIStackDepthAsserts, true, \ "Enable JVMTI asserts related to stack depth checks") \ \ /* flags for performance data collection */ \ \ product(bool, UsePerfData, true, \ "Flag to disable jvmstat instrumentation for performance testing "\ "and problem isolation purposes") \ \ product(bool, PerfDataSaveToFile, false, \ "Save PerfData memory to hsperfdata_ file on exit") \ \ product(ccstr, PerfDataSaveFile, nullptr, \ "Save PerfData memory to the specified absolute pathname. " \ "The string %p in the file name (if present) " \ "will be replaced by pid") \ \ product(bool, PerfDisableSharedMem, false, \ "Store performance data in standard memory") \ \ product(int, PerfDataMemorySize, 32*K, \ "Size of performance data memory region. Will be rounded " \ "up to a multiple of the native os page size.") \ range(128, 32*64*K) \ \ product(int, PerfMaxStringConstLength, 1024, \ "Maximum PerfStringConstant string length before truncation") \ range(32, 32*K) \ \ product(bool, PerfAllowAtExitRegistration, false, \ "Allow registration of atexit() methods") \ \ product(bool, PerfBypassFileSystemCheck, false, \ "Bypass Win32 file system criteria checks (Windows Only)") \ \ product(int, UnguardOnExecutionViolation, 0, \ "Unguard page and retry on no-execute fault (Win32 only) " \ "0=off, 1=conservative, 2=aggressive") \ range(0, 2) \ \ /* Serviceability Support */ \ \ product(bool, ManagementServer, false, \ "Create JMX Management Server") \ \ product(bool, DisableAttachMechanism, false, \ "Disable mechanism that allows tools to attach to this VM") \ \ product(bool, StartAttachListener, false, \ "Always start Attach Listener at VM startup") \ \ product(bool, EnableDynamicAgentLoading, true, \ "Allow tools to load agents with the attach mechanism") \ \ product(bool, PrintConcurrentLocks, false, MANAGEABLE, \ "Print java.util.concurrent locks in thread dump") \ \ product(bool, PrintMethodHandleStubs, false, DIAGNOSTIC, \ "Print generated stub code for method handles") \ \ product(bool, VerifyMethodHandles, trueInDebug, DIAGNOSTIC, \ "perform extra checks when constructing method handles") \ \ product(bool, ShowHiddenFrames, false, DIAGNOSTIC, \ "show method handle implementation frames (usually hidden)") \ \ product(bool, ShowCarrierFrames, false, DIAGNOSTIC, \ "show virtual threads' carrier frames in exceptions") \ \ product(bool, TrustFinalNonStaticFields, false, EXPERIMENTAL, \ "trust final non-static declarations for constant folding") \ \ product(bool, FoldStableValues, true, DIAGNOSTIC, \ "Optimize loads from stable fields (marked w/ @Stable)") \ \ product(int, UseBootstrapCallInfo, 1, DIAGNOSTIC, \ "0: when resolving InDy or ConDy, force all BSM arguments to be " \ "resolved before the bootstrap method is called; 1: when a BSM " \ "that may accept a BootstrapCallInfo is detected, use that API " \ "to pass BSM arguments, which allows the BSM to delay their " \ "resolution; 2+: stress test the BCI API by calling more BSMs " \ "via that API, instead of with the eagerly-resolved array.") \ \ product(bool, PauseAtStartup, false, DIAGNOSTIC, \ "Causes the VM to pause at startup time and wait for the pause " \ "file to be removed (default: ./vm.paused.)") \ \ product(ccstr, PauseAtStartupFile, nullptr, DIAGNOSTIC, \ "The file to create and for whose removal to await when pausing " \ "at startup. (default: ./vm.paused.)") \ \ product(bool, PauseAtExit, false, DIAGNOSTIC, \ "Pause and wait for keypress on exit if a debugger is attached") \ \ product(bool, DTraceMethodProbes, false, \ "Enable dtrace tool probes for method-entry and method-exit") \ \ product(bool, DTraceAllocProbes, false, \ "Enable dtrace tool probes for object allocation") \ \ product(bool, DTraceMonitorProbes, false, \ "Enable dtrace tool probes for monitor events") \ \ product(bool, RelaxAccessControlCheck, false, \ "Relax the access control checks in the verifier") \ \ product(uintx, StringTableSize, defaultStringTableSize, \ "Number of buckets in the interned String table " \ "(will be rounded to nearest higher power of 2)") \ range(minimumStringTableSize, 16777216ul /* 2^24 */) \ \ product(uintx, SymbolTableSize, defaultSymbolTableSize, EXPERIMENTAL, \ "Number of buckets in the JVM internal Symbol table") \ range(minimumSymbolTableSize, 16777216ul /* 2^24 */) \ \ product(bool, UseStringDeduplication, false, \ "Use string deduplication") \ \ product(uint, StringDeduplicationAgeThreshold, 3, \ "A string must reach this age (or be promoted to an old region) " \ "to be considered for deduplication") \ range(1, markWord::max_age) \ \ product(size_t, StringDeduplicationInitialTableSize, 500, EXPERIMENTAL, \ "Approximate initial number of buckets in the table") \ range(1, 1 * G) \ \ product(double, StringDeduplicationGrowTableLoad, 14.0, EXPERIMENTAL, \ "Entries per bucket above which the table should be expanded") \ range(0.1, 1000.0) \ \ product(double, StringDeduplicationShrinkTableLoad, 1.0, EXPERIMENTAL, \ "Entries per bucket below which the table should be shrunk") \ range(0.01, 100.0) \ \ product(double, StringDeduplicationTargetTableLoad, 7.0, EXPERIMENTAL, \ "Desired entries per bucket when resizing the table") \ range(0.01, 1000.0) \ \ product(size_t, StringDeduplicationCleanupDeadMinimum, 100, EXPERIMENTAL, \ "Minimum number of dead table entries for cleaning the table") \ \ product(int, StringDeduplicationCleanupDeadPercent, 5, EXPERIMENTAL, \ "Minimum percentage of dead table entries for cleaning the table") \ range(1, 100) \ \ product(bool, StringDeduplicationResizeALot, false, DIAGNOSTIC, \ "Force more frequent table resizing") \ \ product(uint64_t, StringDeduplicationHashSeed, 0, DIAGNOSTIC, \ "Seed for the table hashing function; 0 requests computed seed") \ \ product(bool, WhiteBoxAPI, false, DIAGNOSTIC, \ "Enable internal testing APIs") \ \ product(bool, AlwaysAtomicAccesses, false, EXPERIMENTAL, \ "Accesses to all variables should always be atomic") \ \ product(bool, UseUnalignedAccesses, false, DIAGNOSTIC, \ "Use unaligned memory accesses in Unsafe") \ \ product_pd(bool, PreserveFramePointer, \ "Use the FP register for holding the frame pointer " \ "and not as a general purpose register.") \ \ product(size_t, AsyncLogBufferSize, 2*M, \ "Memory budget (in bytes) for the buffer of Asynchronous " \ "Logging (-Xlog:async).") \ range(DEBUG_ONLY(192) NOT_DEBUG(100*K), 50*M) \ \ product(bool, CheckIntrinsics, true, DIAGNOSTIC, \ "When a class C is loaded, check that " \ "(1) all intrinsics defined by the VM for class C are present "\ "in the loaded class file and are marked with the " \ "@IntrinsicCandidate annotation, that " \ "(2) there is an intrinsic registered for all loaded methods " \ "that are annotated with the @IntrinsicCandidate annotation, " \ "and that " \ "(3) no orphan methods exist for class C (i.e., methods for " \ "which the VM declares an intrinsic but that are not declared "\ "in the loaded class C. " \ "Check (3) is available only in debug builds.") \ \ product_pd(intx, InitArrayShortSize, DIAGNOSTIC, \ "Threshold small size (in bytes) for clearing arrays. " \ "Anything this size or smaller may get converted to discrete " \ "scalar stores.") \ range(0, max_intx) \ constraint(InitArrayShortSizeConstraintFunc, AfterErgo) \ \ product(ccstr, AllocateHeapAt, nullptr, \ "Path to the directory where a temporary file will be created " \ "to use as the backing store for Java Heap.") \ \ product_pd(bool, VMContinuations, EXPERIMENTAL, \ "Enable VM continuations support") \ \ develop(bool, LoomDeoptAfterThaw, false, \ "Deopt stack after thaw") \ \ develop(bool, LoomVerifyAfterThaw, false, \ "Verify stack after thaw") \ \ develop(bool, VerifyContinuations, false, \ "Verify continuation consistency") \ \ develop(bool, UseContinuationFastPath, true, \ "Use fast-path frame walking in continuations") \ \ develop(int, VerifyMetaspaceInterval, DEBUG_ONLY(500) NOT_DEBUG(0), \ "Run periodic metaspace verifications (0 - none, " \ "1 - always, >1 every nth interval)") \ \ product(bool, ShowRegistersOnAssert, true, DIAGNOSTIC, \ "On internal errors, include registers in error report.") \ \ product(bool, UseSwitchProfiling, true, DIAGNOSTIC, \ "leverage profiling for table/lookup switch") \ \ develop(bool, TraceMemoryWriteback, false, \ "Trace memory writeback operations") \ \ JFR_ONLY(product(bool, FlightRecorder, false, \ "(Deprecated) Enable Flight Recorder")) \ \ JFR_ONLY(product(ccstr, FlightRecorderOptions, nullptr, \ "Flight Recorder options")) \ \ JFR_ONLY(product(ccstr, StartFlightRecording, nullptr, \ "Start flight recording with options")) \ \ product(bool, UseFastUnorderedTimeStamps, false, EXPERIMENTAL, \ "Use platform unstable time where supported for timestamps only") \ \ product(bool, DeoptimizeNMethodBarriersALot, false, DIAGNOSTIC, \ "Make nmethod barriers deoptimise a lot.") \ \ develop(bool, VerifyCrossModifyFence, \ false AARCH64_ONLY(DEBUG_ONLY(||true)), \ "Mark all threads after a safepoint, and clear on a modify " \ "fence. Add cleanliness checks.") \ \ product(int, LockingMode, LM_LIGHTWEIGHT, \ "(Deprecated) Select locking mode: " \ "0: (Deprecated) monitors only (LM_MONITOR), " \ "1: (Deprecated) monitors & legacy stack-locking (LM_LEGACY), " \ "2: monitors & new lightweight locking (LM_LIGHTWEIGHT, default)") \ range(0, 2) \ \ product(bool, UseObjectMonitorTable, false, DIAGNOSTIC, \ "With Lightweight Locking mode, use a table to record inflated " \ "monitors rather than the first word of the object.") \ \ product(int, LightweightFastLockingSpins, 13, DIAGNOSTIC, \ "Specifies the number of times lightweight fast locking will " \ "attempt to CAS the markWord before inflating. Between each " \ "CAS it will spin for exponentially more time, resulting in " \ "a total number of spins on the order of O(2^value)") \ range(1, 30) \ \ product(uint, TrimNativeHeapInterval, 0, \ "Interval, in ms, at which the JVM will trim the native heap if " \ "the platform supports that. Lower values will reclaim memory " \ "more eagerly at the cost of higher overhead. A value of 0 " \ "(default) disables native heap trimming.") \ range(0, UINT_MAX) \ \ develop(bool, SimulateFullAddressSpace, false, \ "Simulates a very populated, fragmented address space; no " \ "targeted reservations will succeed.") \ \ product(bool, ProfileExceptionHandlers, true, \ "Profile exception handlers") \ \ product(bool, AlwaysRecordEvolDependencies, true, EXPERIMENTAL, \ "Unconditionally record nmethod dependencies on class " \ "rewriting/transformation independently of the JVMTI " \ "can_{retransform/redefine}_classes capabilities.") \ \ product(bool, UseSecondarySupersCache, true, DIAGNOSTIC, \ "Use secondary supers cache during subtype checks.") \ \ product(bool, UseSecondarySupersTable, false, DIAGNOSTIC, \ "Use hash table to lookup secondary supers.") \ \ product(bool, VerifySecondarySupers, false, DIAGNOSTIC, \ "Check that linear and hashed secondary lookups return the same result.") \ \ product(bool, StressSecondarySupers, false, DIAGNOSTIC, \ "Use a terrible hash function in order to generate many collisions.") \ \ product(bool, UseThreadsLockThrottleLock, true, DIAGNOSTIC, \ "Use an extra lock during Thread start and exit to alleviate" \ "contention on Threads_lock.") \ \ develop(uint, BinarySearchThreshold, 16, \ "Minimal number of elements in a sorted collection to prefer" \ "binary search over simple linear search." ) \ // end of RUNTIME_FLAGS DECLARE_FLAGS(LP64_RUNTIME_FLAGS) DECLARE_ARCH_FLAGS(ARCH_FLAGS) DECLARE_FLAGS(RUNTIME_FLAGS) DECLARE_FLAGS(RUNTIME_OS_FLAGS) #endif // SHARE_RUNTIME_GLOBALS_HPP