1 /* 2 * Copyright (c) 1997, 2020, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #ifndef SHARE_GC_SHARED_GC_GLOBALS_HPP 26 #define SHARE_GC_SHARED_GC_GLOBALS_HPP 27 28 #include "runtime/globals_shared.hpp" 29 #include "utilities/macros.hpp" 30 #if INCLUDE_EPSILONGC 31 #include "gc/epsilon/epsilon_globals.hpp" 32 #endif 33 #if INCLUDE_G1GC 34 #include "gc/g1/g1_globals.hpp" 35 #endif 36 #if INCLUDE_PARALLELGC 37 #include "gc/parallel/parallel_globals.hpp" 38 #endif 39 #if INCLUDE_SERIALGC 40 #include "gc/serial/serial_globals.hpp" 41 #endif 42 #if INCLUDE_SHENANDOAHGC 43 #include "gc/shenandoah/shenandoah_globals.hpp" 44 #endif 45 #if INCLUDE_ZGC 46 #include "gc/z/z_globals.hpp" 47 #endif 48 49 #include "runtime/flags/jvmFlag.hpp" 50 PRODUCT_FLAG(bool, UseSerialGC, false, JVMFlag::DEFAULT, 51 "Use the Serial garbage collector"); 52 53 PRODUCT_FLAG(bool, UseG1GC, false, JVMFlag::DEFAULT, 54 "Use the Garbage-First garbage collector"); 55 56 PRODUCT_FLAG(bool, UseParallelGC, false, JVMFlag::DEFAULT, 57 "Use the Parallel garbage collector."); 58 59 PRODUCT_FLAG(bool, UseEpsilonGC, false, JVMFlag::EXPERIMENTAL, 60 "Use the Epsilon (no-op) garbage collector"); 61 62 PRODUCT_FLAG(bool, UseZGC, false, JVMFlag::DEFAULT, 63 "Use the Z garbage collector"); 64 65 PRODUCT_FLAG(bool, UseShenandoahGC, false, JVMFlag::EXPERIMENTAL, 66 "Use the Shenandoah garbage collector"); 67 68 PRODUCT_FLAG(uint, ParallelGCThreads, 0, JVMFlag::CONSTRAINT, 69 "Number of parallel threads parallel gc will use"); 70 FLAG_CONSTRAINT( ParallelGCThreads, (void*)ParallelGCThreadsConstraintFunc, JVMFlag::AfterErgo); 71 72 PRODUCT_FLAG(bool, UseSemaphoreGCThreadsSynchronization, true, JVMFlag::DIAGNOSTIC, 73 "Use semaphore synchronization for the GC Threads, " 74 "instead of synchronization based on mutexes"); 75 76 PRODUCT_FLAG(bool, UseDynamicNumberOfGCThreads, true, JVMFlag::DEFAULT, 77 "Dynamically choose the number of threads up to a maximum of " 78 "ParallelGCThreads parallel collectors will use for garbage " 79 "collection work"); 80 81 PRODUCT_FLAG(bool, InjectGCWorkerCreationFailure, false, JVMFlag::DIAGNOSTIC, 82 "Inject thread creation failures for " 83 "UseDynamicNumberOfGCThreads"); 84 85 PRODUCT_FLAG(size_t, HeapSizePerGCThread, ScaleForWordSize(32*M), JVMFlag::RANGE, 86 "Size of heap (bytes) per GC thread used in calculating the " 87 "number of GC threads"); 88 FLAG_CUSTOM_RANGE( HeapSizePerGCThread, VMPageSize); 89 90 PRODUCT_FLAG(uint, ConcGCThreads, 0, JVMFlag::CONSTRAINT, 91 "Number of threads concurrent gc will use"); 92 FLAG_CONSTRAINT( ConcGCThreads, (void*)ConcGCThreadsConstraintFunc, JVMFlag::AfterErgo); 93 94 PRODUCT_FLAG(bool, AlwaysTenure, false, JVMFlag::DEFAULT, 95 "Always tenure objects in eden (ParallelGC only)"); 96 97 PRODUCT_FLAG(bool, NeverTenure, false, JVMFlag::DEFAULT, 98 "Never tenure objects in eden, may tenure on overflow " 99 "(ParallelGC only)"); 100 101 PRODUCT_FLAG(bool, ScavengeBeforeFullGC, true, JVMFlag::DEFAULT, 102 "Scavenge youngest generation before each full GC."); 103 104 PRODUCT_FLAG(bool, ExplicitGCInvokesConcurrent, false, JVMFlag::DEFAULT, 105 "A System.gc() request invokes a concurrent collection; " 106 "(effective only when using concurrent collectors)"); 107 108 PRODUCT_FLAG(uintx, GCLockerEdenExpansionPercent, 5, JVMFlag::RANGE, 109 "How much the GC can expand the eden by while the GC locker " 110 "is active (as a percentage)"); 111 FLAG_RANGE( GCLockerEdenExpansionPercent, 0, 100); 112 113 PRODUCT_FLAG(uintx, GCLockerRetryAllocationCount, 2, JVMFlag::DIAGNOSTIC | JVMFlag::RANGE, 114 "Number of times to retry allocations when " 115 "blocked by the GC locker"); 116 FLAG_RANGE( GCLockerRetryAllocationCount, 0, max_uintx); 117 118 PRODUCT_FLAG(uintx, ParallelGCBufferWastePct, 10, JVMFlag::RANGE, 119 "Wasted fraction of parallel allocation buffer"); 120 FLAG_RANGE( ParallelGCBufferWastePct, 0, 100); 121 122 PRODUCT_FLAG(uintx, TargetPLABWastePct, 10, JVMFlag::RANGE, 123 "Target wasted space in last buffer as percent of overall " 124 "allocation"); 125 FLAG_RANGE( TargetPLABWastePct, 1, 100); 126 127 PRODUCT_FLAG(uintx, PLABWeight, 75, JVMFlag::RANGE, 128 "Percentage (0-100) used to weight the current sample when " 129 "computing exponentially decaying average for ResizePLAB"); 130 FLAG_RANGE( PLABWeight, 0, 100); 131 132 PRODUCT_FLAG(bool, ResizePLAB, true, JVMFlag::DEFAULT, 133 "Dynamically resize (survivor space) promotion LAB's"); 134 135 PRODUCT_FLAG(int, ParGCArrayScanChunk, 50, JVMFlag::RANGE, 136 "Scan a subset of object array and push remainder, if array is " 137 "bigger than this"); 138 FLAG_RANGE( ParGCArrayScanChunk, 1, max_jint/3); 139 140 PRODUCT_FLAG(bool, AlwaysPreTouch, false, JVMFlag::DEFAULT, 141 "Force all freshly committed pages to be pre-touched"); 142 143 PRODUCT_FLAG(size_t, PreTouchParallelChunkSize, 1 * G, JVMFlag::RANGE, 144 "Per-thread chunk size for parallel memory pre-touch."); 145 FLAG_RANGE( PreTouchParallelChunkSize, 1, SIZE_MAX / 2); 146 147 148 // where does the range max value of (max_jint - 1) come from? 149 PRODUCT_FLAG(size_t, MarkStackSizeMax, NOT_LP64(4*M) LP64_ONLY(512*M), JVMFlag::RANGE, 150 "Maximum size of marking stack"); 151 FLAG_RANGE( MarkStackSizeMax, 1, (max_jint - 1)); 152 153 PRODUCT_FLAG(size_t, MarkStackSize, NOT_LP64(32*K) LP64_ONLY(4*M), JVMFlag::RANGE | JVMFlag::CONSTRAINT, 154 "Size of marking stack"); 155 FLAG_RANGE( MarkStackSize, 1, (max_jint - 1)); 156 FLAG_CONSTRAINT( MarkStackSize, (void*)MarkStackSizeConstraintFunc, JVMFlag::AfterErgo); 157 158 PRODUCT_FLAG(intx, RefDiscoveryPolicy, 0, JVMFlag::RANGE, 159 "Select type of reference discovery policy: " 160 "reference-based(0) or referent-based(1)"); 161 //TODO: to avoid circular dependency, the min/max cannot be declared in header file 162 //FLAG_RANGE( RefDiscoveryPolicy, ReferenceProcessor::DiscoveryPolicyMin,ReferenceProcessor::DiscoveryPolicyMax); 163 164 PRODUCT_FLAG(bool, ParallelRefProcEnabled, false, JVMFlag::DEFAULT, 165 "Enable parallel reference processing whenever possible"); 166 167 PRODUCT_FLAG(bool, ParallelRefProcBalancingEnabled, true, JVMFlag::DEFAULT, 168 "Enable balancing of reference processing queues"); 169 170 PRODUCT_FLAG(size_t, ReferencesPerThread, 1000, JVMFlag::EXPERIMENTAL, 171 "Ergonomically start one thread for this amount of " 172 "references for reference processing if " 173 "ParallelRefProcEnabled is true. Specify 0 to disable and " 174 "use all threads."); 175 176 PRODUCT_FLAG(uintx, InitiatingHeapOccupancyPercent, 45, JVMFlag::RANGE, 177 "The percent occupancy (IHOP) of the current old generation " 178 "capacity above which a concurrent mark cycle will be initiated " 179 "Its value may change over time if adaptive IHOP is enabled, " 180 "otherwise the value remains constant. " 181 "In the latter case a value of 0 will result as frequent as " 182 "possible concurrent marking cycles. A value of 100 disables " 183 "concurrent marking. " 184 "Fragmentation waste in the old generation is not considered " 185 "free space in this calculation. (G1 collector only)"); 186 FLAG_RANGE( InitiatingHeapOccupancyPercent, 0, 100); 187 188 NOTPROD_FLAG(bool, ScavengeALot, false, JVMFlag::DEFAULT, 189 "Force scavenge at every Nth exit from the runtime system " 190 "(N=ScavengeALotInterval)"); 191 192 DEVELOP_FLAG(bool, FullGCALot, false, JVMFlag::DEFAULT, 193 "Force full gc at every Nth exit from the runtime system " 194 "(N=FullGCALotInterval)"); 195 196 NOTPROD_FLAG(bool, GCALotAtAllSafepoints, false, JVMFlag::DEFAULT, 197 "Enforce ScavengeALot/GCALot at all potential safepoints"); 198 199 NOTPROD_FLAG(bool, PromotionFailureALot, false, JVMFlag::DEFAULT, 200 "Use promotion failure handling on every youngest generation " 201 "collection"); 202 203 DEVELOP_FLAG(uintx, PromotionFailureALotCount, 1000, JVMFlag::DEFAULT, 204 "Number of promotion failures occurring at PLAB promotion " 205 "attempts at young collectors"); 206 207 DEVELOP_FLAG(uintx, PromotionFailureALotInterval, 5, JVMFlag::DEFAULT, 208 "Total collections between promotion failures a lot"); 209 210 PRODUCT_FLAG(uintx, WorkStealingSleepMillis, 1, JVMFlag::EXPERIMENTAL, 211 "Sleep time when sleep is used for yields"); 212 213 PRODUCT_FLAG(uintx, WorkStealingYieldsBeforeSleep, 5000, JVMFlag::EXPERIMENTAL, 214 "Number of yields before a sleep is done during work stealing"); 215 216 PRODUCT_FLAG(uintx, WorkStealingHardSpins, 4096, JVMFlag::EXPERIMENTAL, 217 "Number of iterations in a spin loop between checks on " 218 "time out of hard spin"); 219 220 PRODUCT_FLAG(uintx, WorkStealingSpinToYieldRatio, 10, JVMFlag::EXPERIMENTAL, 221 "Ratio of hard spins to calls to yield"); 222 223 DEVELOP_FLAG(uintx, ObjArrayMarkingStride, 2048, JVMFlag::DEFAULT, 224 "Number of object array elements to push onto the marking stack " 225 "before pushing a continuation entry"); 226 227 DEVELOP_FLAG(bool, MetadataAllocationFailALot, false, JVMFlag::DEFAULT, 228 "Fail metadata allocations at intervals controlled by " 229 "MetadataAllocationFailALotInterval"); 230 231 DEVELOP_FLAG(uintx, MetadataAllocationFailALotInterval, 1000, JVMFlag::DEFAULT, 232 "Metadata allocation failure a lot interval"); 233 234 PRODUCT_FLAG(bool, ExecutingUnitTests, false, JVMFlag::DEFAULT, 235 "Whether the JVM is running unit tests or not"); 236 237 PRODUCT_FLAG_PD(bool, UseTLAB, JVMFlag::DEFAULT, 238 "Use thread-local object allocation"); 239 240 PRODUCT_FLAG_PD(bool, ResizeTLAB, JVMFlag::DEFAULT, 241 "Dynamically resize TLAB size for threads"); 242 243 PRODUCT_FLAG(bool, ZeroTLAB, false, JVMFlag::DEFAULT, 244 "Zero out the newly created TLAB"); 245 246 PRODUCT_FLAG(bool, TLABStats, true, JVMFlag::DEFAULT, 247 "Provide more detailed and expensive TLAB statistics."); 248 249 PRODUCT_FLAG_PD(bool, NeverActAsServerClassMachine, JVMFlag::DEFAULT, 250 "Never act like a server-class machine"); 251 252 PRODUCT_FLAG(bool, AlwaysActAsServerClassMachine, false, JVMFlag::DEFAULT, 253 "Always act like a server-class machine"); 254 255 PRODUCT_FLAG_PD(uint64_t, MaxRAM, JVMFlag::RANGE, 256 "Real memory size (in bytes) used to set maximum heap size"); 257 FLAG_RANGE( MaxRAM, 0, 0XFFFFFFFFFFFFFFFF); 258 259 PRODUCT_FLAG(bool, AggressiveHeap, false, JVMFlag::DEFAULT, 260 "Optimize heap options for long-running memory intensive apps"); 261 262 PRODUCT_FLAG(size_t, ErgoHeapSizeLimit, 0, JVMFlag::RANGE, 263 "Maximum ergonomically set heap size (in bytes); zero means use " 264 "MaxRAM * MaxRAMPercentage / 100"); 265 FLAG_RANGE( ErgoHeapSizeLimit, 0, max_uintx); 266 267 PRODUCT_FLAG(uintx, MaxRAMFraction, 4, JVMFlag::RANGE, 268 "Maximum fraction (1/n) of real memory used for maximum heap " 269 "size. " 270 "Deprecated, use MaxRAMPercentage instead"); 271 FLAG_RANGE( MaxRAMFraction, 1, max_uintx); 272 273 PRODUCT_FLAG(uintx, MinRAMFraction, 2, JVMFlag::RANGE, 274 "Minimum fraction (1/n) of real memory used for maximum heap " 275 "size on systems with small physical memory size. " 276 "Deprecated, use MinRAMPercentage instead"); 277 FLAG_RANGE( MinRAMFraction, 1, max_uintx); 278 279 PRODUCT_FLAG(uintx, InitialRAMFraction, 64, JVMFlag::RANGE, 280 "Fraction (1/n) of real memory used for initial heap size. " 281 "Deprecated, use InitialRAMPercentage instead"); 282 FLAG_RANGE( InitialRAMFraction, 1, max_uintx); 283 284 PRODUCT_FLAG(double, MaxRAMPercentage, 25.0, JVMFlag::RANGE, 285 "Maximum percentage of real memory used for maximum heap size"); 286 FLAG_RANGE( MaxRAMPercentage, 0.0, 100.0); 287 288 PRODUCT_FLAG(double, MinRAMPercentage, 50.0, JVMFlag::RANGE, 289 "Minimum percentage of real memory used for maximum heap" 290 "size on systems with small physical memory size"); 291 FLAG_RANGE( MinRAMPercentage, 0.0, 100.0); 292 293 PRODUCT_FLAG(double, InitialRAMPercentage, 1.5625, JVMFlag::RANGE, 294 "Percentage of real memory used for initial heap size"); 295 FLAG_RANGE( InitialRAMPercentage, 0.0, 100.0); 296 297 PRODUCT_FLAG(int, ActiveProcessorCount, -1, JVMFlag::DEFAULT, 298 "Specify the CPU count the VM should use and report as active"); 299 300 DEVELOP_FLAG(uintx, MaxVirtMemFraction, 2, JVMFlag::DEFAULT, 301 "Maximum fraction (1/n) of virtual memory used for ergonomically " 302 "determining maximum heap size"); 303 304 PRODUCT_FLAG(bool, UseAdaptiveSizePolicy, true, JVMFlag::DEFAULT, 305 "Use adaptive generation sizing policies"); 306 307 PRODUCT_FLAG(bool, UsePSAdaptiveSurvivorSizePolicy, true, JVMFlag::DEFAULT, 308 "Use adaptive survivor sizing policies"); 309 310 PRODUCT_FLAG(bool, UseAdaptiveGenerationSizePolicyAtMinorCollection, true, JVMFlag::DEFAULT, 311 "Use adaptive young-old sizing policies at minor collections"); 312 313 PRODUCT_FLAG(bool, UseAdaptiveGenerationSizePolicyAtMajorCollection, true, JVMFlag::DEFAULT, 314 "Use adaptive young-old sizing policies at major collections"); 315 316 PRODUCT_FLAG(bool, UseAdaptiveSizePolicyWithSystemGC, false, JVMFlag::DEFAULT, 317 "Include statistics from System.gc() for adaptive size policy"); 318 319 PRODUCT_FLAG(bool, UseAdaptiveGCBoundary, false, JVMFlag::DEFAULT, 320 "Allow young-old boundary to move"); 321 322 DEVELOP_FLAG(intx, PSAdaptiveSizePolicyResizeVirtualSpaceAlot, -1, JVMFlag::RANGE, 323 "Resize the virtual spaces of the young or old generations"); 324 FLAG_RANGE( PSAdaptiveSizePolicyResizeVirtualSpaceAlot, -1, 1); 325 326 PRODUCT_FLAG(uintx, AdaptiveSizeThroughPutPolicy, 0, JVMFlag::RANGE, 327 "Policy for changing generation size for throughput goals"); 328 FLAG_RANGE( AdaptiveSizeThroughPutPolicy, 0, 1); 329 330 PRODUCT_FLAG(uintx, AdaptiveSizePolicyInitializingSteps, 20, JVMFlag::RANGE, 331 "Number of steps where heuristics is used before data is used"); 332 FLAG_RANGE( AdaptiveSizePolicyInitializingSteps, 0, max_uintx); 333 334 DEVELOP_FLAG(uintx, AdaptiveSizePolicyReadyThreshold, 5, JVMFlag::DEFAULT, 335 "Number of collections before the adaptive sizing is started"); 336 337 PRODUCT_FLAG(uintx, AdaptiveSizePolicyOutputInterval, 0, JVMFlag::RANGE, 338 "Collection interval for printing information; zero means never"); 339 FLAG_RANGE( AdaptiveSizePolicyOutputInterval, 0, max_uintx); 340 341 PRODUCT_FLAG(bool, UseAdaptiveSizePolicyFootprintGoal, true, JVMFlag::DEFAULT, 342 "Use adaptive minimum footprint as a goal"); 343 344 PRODUCT_FLAG(uintx, AdaptiveSizePolicyWeight, 10, JVMFlag::RANGE, 345 "Weight given to exponential resizing, between 0 and 100"); 346 FLAG_RANGE( AdaptiveSizePolicyWeight, 0, 100); 347 348 PRODUCT_FLAG(uintx, AdaptiveTimeWeight, 25, JVMFlag::RANGE, 349 "Weight given to time in adaptive policy, between 0 and 100"); 350 FLAG_RANGE( AdaptiveTimeWeight, 0, 100); 351 352 PRODUCT_FLAG(uintx, PausePadding, 1, JVMFlag::RANGE, 353 "How much buffer to keep for pause time"); 354 FLAG_RANGE( PausePadding, 0, max_juint); 355 356 PRODUCT_FLAG(uintx, PromotedPadding, 3, JVMFlag::RANGE, 357 "How much buffer to keep for promotion failure"); 358 FLAG_RANGE( PromotedPadding, 0, max_juint); 359 360 PRODUCT_FLAG(uintx, SurvivorPadding, 3, JVMFlag::RANGE, 361 "How much buffer to keep for survivor overflow"); 362 FLAG_RANGE( SurvivorPadding, 0, max_juint); 363 364 PRODUCT_FLAG(uintx, ThresholdTolerance, 10, JVMFlag::RANGE, 365 "Allowed collection cost difference between generations"); 366 FLAG_RANGE( ThresholdTolerance, 0, 100); 367 368 PRODUCT_FLAG(uintx, AdaptiveSizePolicyCollectionCostMargin, 50, JVMFlag::RANGE, 369 "If collection costs are within margin, reduce both by full " 370 "delta"); 371 FLAG_RANGE( AdaptiveSizePolicyCollectionCostMargin, 0, 100); 372 373 PRODUCT_FLAG(uintx, YoungGenerationSizeIncrement, 20, JVMFlag::RANGE, 374 "Adaptive size percentage change in young generation"); 375 FLAG_RANGE( YoungGenerationSizeIncrement, 0, 100); 376 377 PRODUCT_FLAG(uintx, YoungGenerationSizeSupplement, 80, JVMFlag::RANGE, 378 "Supplement to YoungedGenerationSizeIncrement used at startup"); 379 FLAG_RANGE( YoungGenerationSizeSupplement, 0, 100); 380 381 PRODUCT_FLAG(uintx, YoungGenerationSizeSupplementDecay, 8, JVMFlag::RANGE, 382 "Decay factor to YoungedGenerationSizeSupplement"); 383 FLAG_RANGE( YoungGenerationSizeSupplementDecay, 1, max_uintx); 384 385 PRODUCT_FLAG(uintx, TenuredGenerationSizeIncrement, 20, JVMFlag::RANGE, 386 "Adaptive size percentage change in tenured generation"); 387 FLAG_RANGE( TenuredGenerationSizeIncrement, 0, 100); 388 389 PRODUCT_FLAG(uintx, TenuredGenerationSizeSupplement, 80, JVMFlag::RANGE, 390 "Supplement to TenuredGenerationSizeIncrement used at startup"); 391 FLAG_RANGE( TenuredGenerationSizeSupplement, 0, 100); 392 393 PRODUCT_FLAG(uintx, TenuredGenerationSizeSupplementDecay, 2, JVMFlag::RANGE, 394 "Decay factor to TenuredGenerationSizeIncrement"); 395 FLAG_RANGE( TenuredGenerationSizeSupplementDecay, 1, max_uintx); 396 397 PRODUCT_FLAG(uintx, MaxGCPauseMillis, max_uintx - 1, JVMFlag::RANGE | JVMFlag::CONSTRAINT, 398 "Adaptive size policy maximum GC pause time goal in millisecond, " 399 "or (G1 Only) the maximum GC time per MMU time slice"); 400 FLAG_RANGE( MaxGCPauseMillis, 1, max_uintx - 1); 401 FLAG_CONSTRAINT( MaxGCPauseMillis, (void*)MaxGCPauseMillisConstraintFunc, JVMFlag::AfterErgo); 402 403 PRODUCT_FLAG(uintx, GCPauseIntervalMillis, 0, JVMFlag::CONSTRAINT, 404 "Time slice for MMU specification"); 405 FLAG_CONSTRAINT( GCPauseIntervalMillis, (void*)GCPauseIntervalMillisConstraintFunc, JVMFlag::AfterErgo); 406 407 PRODUCT_FLAG(uintx, MaxGCMinorPauseMillis, max_uintx, JVMFlag::RANGE, 408 "Adaptive size policy maximum GC minor pause time goal " 409 "in millisecond"); 410 FLAG_RANGE( MaxGCMinorPauseMillis, 0, max_uintx); 411 412 PRODUCT_FLAG(uintx, GCTimeRatio, 99, JVMFlag::RANGE, 413 "Adaptive size policy application time to GC time ratio"); 414 FLAG_RANGE( GCTimeRatio, 0, max_juint); 415 416 PRODUCT_FLAG(uintx, AdaptiveSizeDecrementScaleFactor, 4, JVMFlag::RANGE, 417 "Adaptive size scale down factor for shrinking"); 418 FLAG_RANGE( AdaptiveSizeDecrementScaleFactor, 1, max_uintx); 419 420 PRODUCT_FLAG(bool, UseAdaptiveSizeDecayMajorGCCost, true, JVMFlag::DEFAULT, 421 "Adaptive size decays the major cost for long major intervals"); 422 423 PRODUCT_FLAG(uintx, AdaptiveSizeMajorGCDecayTimeScale, 10, JVMFlag::RANGE, 424 "Time scale over which major costs decay"); 425 FLAG_RANGE( AdaptiveSizeMajorGCDecayTimeScale, 0, max_uintx); 426 427 PRODUCT_FLAG(uintx, MinSurvivorRatio, 3, JVMFlag::RANGE, 428 "Minimum ratio of young generation/survivor space size"); 429 FLAG_RANGE( MinSurvivorRatio, 3, max_uintx); 430 431 PRODUCT_FLAG(uintx, InitialSurvivorRatio, 8, JVMFlag::RANGE, 432 "Initial ratio of young generation/survivor space size"); 433 FLAG_RANGE( InitialSurvivorRatio, 0, max_uintx); 434 435 PRODUCT_FLAG(size_t, BaseFootPrintEstimate, 256*M, JVMFlag::RANGE, 436 "Estimate of footprint other than Java Heap"); 437 FLAG_RANGE( BaseFootPrintEstimate, 0, max_uintx); 438 439 PRODUCT_FLAG(bool, UseGCOverheadLimit, true, JVMFlag::DEFAULT, 440 "Use policy to limit of proportion of time spent in GC " 441 "before an OutOfMemory error is thrown"); 442 443 PRODUCT_FLAG(uintx, GCTimeLimit, 98, JVMFlag::RANGE, 444 "Limit of the proportion of time spent in GC before " 445 "an OutOfMemoryError is thrown (used with GCHeapFreeLimit)"); 446 FLAG_RANGE( GCTimeLimit, 0, 100); 447 448 PRODUCT_FLAG(uintx, GCHeapFreeLimit, 2, JVMFlag::RANGE, 449 "Minimum percentage of free space after a full GC before an " 450 "OutOfMemoryError is thrown (used with GCTimeLimit)"); 451 FLAG_RANGE( GCHeapFreeLimit, 0, 100); 452 453 DEVELOP_FLAG(uintx, GCOverheadLimitThreshold, 5, JVMFlag::RANGE, 454 "Number of consecutive collections before gc time limit fires"); 455 FLAG_RANGE( GCOverheadLimitThreshold, 1, max_uintx); 456 457 PRODUCT_FLAG(intx, PrefetchCopyIntervalInBytes, -1, JVMFlag::RANGE, 458 "How far ahead to prefetch destination area (<= 0 means off)"); 459 FLAG_RANGE( PrefetchCopyIntervalInBytes, -1, max_jint); 460 461 PRODUCT_FLAG(intx, PrefetchScanIntervalInBytes, -1, JVMFlag::RANGE, 462 "How far ahead to prefetch scan area (<= 0 means off)"); 463 FLAG_RANGE( PrefetchScanIntervalInBytes, -1, max_jint); 464 465 PRODUCT_FLAG(intx, PrefetchFieldsAhead, -1, JVMFlag::RANGE, 466 "How many fields ahead to prefetch in oop scan (<= 0 means off)"); 467 FLAG_RANGE( PrefetchFieldsAhead, -1, max_jint); 468 469 PRODUCT_FLAG(bool, VerifyDuringStartup, false, JVMFlag::DIAGNOSTIC, 470 "Verify memory system before executing any Java code " 471 "during VM initialization"); 472 473 PRODUCT_FLAG(bool, VerifyBeforeExit, trueInDebug, JVMFlag::DIAGNOSTIC, 474 "Verify system before exiting"); 475 476 PRODUCT_FLAG(bool, VerifyBeforeGC, false, JVMFlag::DIAGNOSTIC, 477 "Verify memory system before GC"); 478 479 PRODUCT_FLAG(bool, VerifyAfterGC, false, JVMFlag::DIAGNOSTIC, 480 "Verify memory system after GC"); 481 482 PRODUCT_FLAG(bool, VerifyDuringGC, false, JVMFlag::DIAGNOSTIC, 483 "Verify memory system during GC (between phases)"); 484 485 PRODUCT_FLAG(ccstr, VerifyGCType, "", JVMFlag::DIAGNOSTIC | JVMFlag::STRINGLIST, 486 "GC type(s) to verify when Verify*GC is enabled." 487 "Available types are collector specific."); 488 489 PRODUCT_FLAG(ccstr, VerifySubSet, "", JVMFlag::DIAGNOSTIC | JVMFlag::STRINGLIST, 490 "Memory sub-systems to verify when Verify*GC flag(s) " 491 "are enabled. One or more sub-systems can be specified " 492 "in a comma separated string. Sub-systems are: " 493 "threads, heap, symbol_table, string_table, codecache, " 494 "dictionary, classloader_data_graph, metaspace, jni_handles, " 495 "codecache_oops"); 496 497 PRODUCT_FLAG(bool, GCParallelVerificationEnabled, true, JVMFlag::DIAGNOSTIC, 498 "Enable parallel memory system verification"); 499 500 PRODUCT_FLAG(bool, DeferInitialCardMark, false, JVMFlag::DIAGNOSTIC, 501 "When +ReduceInitialCardMarks, explicitly defer any that " 502 "may arise from new_pre_store_barrier"); 503 504 PRODUCT_FLAG(bool, UseCondCardMark, false, JVMFlag::DEFAULT, 505 "Check for already marked card before updating card table"); 506 507 PRODUCT_FLAG(bool, VerifyRememberedSets, false, JVMFlag::DIAGNOSTIC, 508 "Verify GC remembered sets"); 509 510 PRODUCT_FLAG(bool, VerifyObjectStartArray, true, JVMFlag::DIAGNOSTIC, 511 "Verify GC object start array if verify before/after"); 512 513 PRODUCT_FLAG(bool, DisableExplicitGC, false, JVMFlag::DEFAULT, 514 "Ignore calls to System.gc()"); 515 516 PRODUCT_FLAG(bool, PrintGC, false, JVMFlag::DEFAULT, 517 "Print message at garbage collection. " 518 "Deprecated, use -Xlog:gc instead."); 519 520 PRODUCT_FLAG(bool, PrintGCDetails, false, JVMFlag::DEFAULT, 521 "Print more details at garbage collection. " 522 "Deprecated, use -Xlog:gc* instead."); 523 524 DEVELOP_FLAG(intx, ConcGCYieldTimeout, 0, JVMFlag::RANGE, 525 "If non-zero, assert that GC threads yield within this " 526 "number of milliseconds"); 527 FLAG_RANGE( ConcGCYieldTimeout, 0, max_intx); 528 529 NOTPROD_FLAG(intx, ScavengeALotInterval, 1, JVMFlag::DEFAULT, 530 "Interval between which scavenge will occur with +ScavengeALot"); 531 532 NOTPROD_FLAG(intx, FullGCALotInterval, 1, JVMFlag::DEFAULT, 533 "Interval between which full gc will occur with +FullGCALot"); 534 535 NOTPROD_FLAG(intx, FullGCALotStart, 0, JVMFlag::DEFAULT, 536 "For which invocation to start FullGCAlot"); 537 538 NOTPROD_FLAG(intx, FullGCALotDummies, 32*K, JVMFlag::DEFAULT, 539 "Dummy object allocated with +FullGCALot, forcing all objects " 540 "to move"); 541 542 543 // gc parameters 544 PRODUCT_FLAG(size_t, MinHeapSize, 0, JVMFlag::CONSTRAINT, 545 "Minimum heap size (in bytes); zero means use ergonomics"); 546 FLAG_CONSTRAINT( MinHeapSize, (void*)MinHeapSizeConstraintFunc, JVMFlag::AfterErgo); 547 548 PRODUCT_FLAG(size_t, InitialHeapSize, 0, JVMFlag::CONSTRAINT, 549 "Initial heap size (in bytes); zero means use ergonomics"); 550 FLAG_CONSTRAINT( InitialHeapSize, (void*)InitialHeapSizeConstraintFunc, JVMFlag::AfterErgo); 551 552 PRODUCT_FLAG(size_t, MaxHeapSize, ScaleForWordSize(96*M), JVMFlag::CONSTRAINT, 553 "Maximum heap size (in bytes)"); 554 FLAG_CONSTRAINT( MaxHeapSize, (void*)MaxHeapSizeConstraintFunc, JVMFlag::AfterErgo); 555 556 PRODUCT_FLAG(size_t, SoftMaxHeapSize, 0, JVMFlag::MANAGEABLE | JVMFlag::CONSTRAINT, 557 "Soft limit for maximum heap size (in bytes)"); 558 FLAG_CONSTRAINT( SoftMaxHeapSize, (void*)SoftMaxHeapSizeConstraintFunc, JVMFlag::AfterMemoryInit); 559 560 PRODUCT_FLAG(size_t, OldSize, ScaleForWordSize(4*M), JVMFlag::RANGE, 561 "Initial tenured generation size (in bytes)"); 562 FLAG_RANGE( OldSize, 0, max_uintx); 563 564 PRODUCT_FLAG(size_t, NewSize, ScaleForWordSize(1*M), JVMFlag::CONSTRAINT, 565 "Initial new generation size (in bytes)"); 566 FLAG_CONSTRAINT( NewSize, (void*)NewSizeConstraintFunc, JVMFlag::AfterErgo); 567 568 PRODUCT_FLAG(size_t, MaxNewSize, max_uintx, JVMFlag::RANGE, 569 "Maximum new generation size (in bytes), max_uintx means set " 570 "ergonomically"); 571 FLAG_RANGE( MaxNewSize, 0, max_uintx); 572 573 PRODUCT_FLAG_PD(size_t, HeapBaseMinAddress, JVMFlag::CONSTRAINT, 574 "OS specific low limit for heap base address"); 575 FLAG_CONSTRAINT( HeapBaseMinAddress, (void*)HeapBaseMinAddressConstraintFunc, JVMFlag::AfterErgo); 576 577 PRODUCT_FLAG(size_t, PretenureSizeThreshold, 0, JVMFlag::RANGE, 578 "Maximum size in bytes of objects allocated in DefNew " 579 "generation; zero means no maximum"); 580 FLAG_RANGE( PretenureSizeThreshold, 0, max_uintx); 581 582 PRODUCT_FLAG(size_t, MinTLABSize, 2*K, JVMFlag::RANGE | JVMFlag::CONSTRAINT, 583 "Minimum allowed TLAB size (in bytes)"); 584 FLAG_RANGE( MinTLABSize, 1, max_uintx/2); 585 FLAG_CONSTRAINT( MinTLABSize, (void*)MinTLABSizeConstraintFunc, JVMFlag::AfterMemoryInit); 586 587 PRODUCT_FLAG(size_t, TLABSize, 0, JVMFlag::CONSTRAINT, 588 "Starting TLAB size (in bytes); zero means set ergonomically"); 589 FLAG_CONSTRAINT( TLABSize, (void*)TLABSizeConstraintFunc, JVMFlag::AfterMemoryInit); 590 591 PRODUCT_FLAG(size_t, YoungPLABSize, 4096, JVMFlag::CONSTRAINT, 592 "Size of young gen promotion LAB's (in HeapWords)"); 593 FLAG_CONSTRAINT( YoungPLABSize, (void*)YoungPLABSizeConstraintFunc, JVMFlag::AfterMemoryInit); 594 595 PRODUCT_FLAG(size_t, OldPLABSize, 1024, JVMFlag::CONSTRAINT, 596 "Size of old gen promotion LAB's (in HeapWords)"); 597 FLAG_CONSTRAINT( OldPLABSize, (void*)OldPLABSizeConstraintFunc, JVMFlag::AfterMemoryInit); 598 599 PRODUCT_FLAG(uintx, TLABAllocationWeight, 35, JVMFlag::RANGE, 600 "Allocation averaging weight"); 601 FLAG_RANGE( TLABAllocationWeight, 0, 100); 602 603 604 // Limit the lower bound of this flag to 1 as it is used 605 // in a division expression. 606 PRODUCT_FLAG(uintx, TLABWasteTargetPercent, 1, JVMFlag::RANGE, 607 "Percentage of Eden that can be wasted"); 608 FLAG_RANGE( TLABWasteTargetPercent, 1, 100); 609 610 PRODUCT_FLAG(uintx, TLABRefillWasteFraction, 64, JVMFlag::RANGE, 611 "Maximum TLAB waste at a refill (internal fragmentation)"); 612 FLAG_RANGE( TLABRefillWasteFraction, 1, max_juint); 613 614 PRODUCT_FLAG(uintx, TLABWasteIncrement, 4, JVMFlag::RANGE | JVMFlag::CONSTRAINT, 615 "Increment allowed waste at slow allocation"); 616 FLAG_RANGE( TLABWasteIncrement, 0, max_jint); 617 FLAG_CONSTRAINT( TLABWasteIncrement, (void*)TLABWasteIncrementConstraintFunc, JVMFlag::AfterMemoryInit); 618 619 PRODUCT_FLAG(uintx, SurvivorRatio, 8, JVMFlag::RANGE | JVMFlag::CONSTRAINT, 620 "Ratio of eden/survivor space size"); 621 FLAG_RANGE( SurvivorRatio, 1, max_uintx-2); 622 FLAG_CONSTRAINT( SurvivorRatio, (void*)SurvivorRatioConstraintFunc, JVMFlag::AfterMemoryInit); 623 624 PRODUCT_FLAG(uintx, NewRatio, 2, JVMFlag::RANGE, 625 "Ratio of old/new generation sizes"); 626 FLAG_RANGE( NewRatio, 0, max_uintx-1); 627 628 PRODUCT_FLAG_PD(size_t, NewSizeThreadIncrease, JVMFlag::RANGE, 629 "Additional size added to desired new generation size per " 630 "non-daemon thread (in bytes)"); 631 FLAG_RANGE( NewSizeThreadIncrease, 0, max_uintx); 632 633 PRODUCT_FLAG(uintx, QueuedAllocationWarningCount, 0, JVMFlag::RANGE, 634 "Number of times an allocation that queues behind a GC " 635 "will retry before printing a warning"); 636 FLAG_RANGE( QueuedAllocationWarningCount, 0, max_uintx); 637 638 PRODUCT_FLAG(uintx, VerifyGCStartAt, 0, JVMFlag::DIAGNOSTIC | JVMFlag::RANGE, 639 "GC invoke count where +VerifyBefore/AfterGC kicks in"); 640 FLAG_RANGE( VerifyGCStartAt, 0, max_uintx); 641 642 PRODUCT_FLAG(intx, VerifyGCLevel, 0, JVMFlag::DIAGNOSTIC | JVMFlag::RANGE, 643 "Generation level at which to start +VerifyBefore/AfterGC"); 644 FLAG_RANGE( VerifyGCLevel, 0, 1); 645 646 PRODUCT_FLAG(uintx, MaxTenuringThreshold, 15, JVMFlag::RANGE | JVMFlag::CONSTRAINT, 647 "Maximum value for tenuring threshold"); 648 //TODO: to avoid circular dependency, the min/max cannot be declared in header file 649 //FLAG_RANGE( MaxTenuringThreshold, 0, markWord::max_age + 1); 650 FLAG_CONSTRAINT( MaxTenuringThreshold, (void*)MaxTenuringThresholdConstraintFunc, JVMFlag::AfterErgo); 651 652 PRODUCT_FLAG(uintx, InitialTenuringThreshold, 7, JVMFlag::RANGE | JVMFlag::CONSTRAINT, 653 "Initial value for tenuring threshold"); 654 //TODO: to avoid circular dependency, the min/max cannot be declared in header file 655 //FLAG_RANGE( InitialTenuringThreshold, 0, markWord::max_age + 1); 656 FLAG_CONSTRAINT( InitialTenuringThreshold, (void*)InitialTenuringThresholdConstraintFunc, JVMFlag::AfterErgo); 657 658 PRODUCT_FLAG(uintx, TargetSurvivorRatio, 50, JVMFlag::RANGE, 659 "Desired percentage of survivor space used after scavenge"); 660 FLAG_RANGE( TargetSurvivorRatio, 0, 100); 661 662 PRODUCT_FLAG(uintx, MarkSweepDeadRatio, 5, JVMFlag::RANGE, 663 "Percentage (0-100) of the old gen allowed as dead wood. " 664 "Serial mark sweep treats this as both the minimum and maximum " 665 "value. " 666 "Par compact uses a variable scale based on the density of the " 667 "generation and treats this as the maximum value when the heap " 668 "is either completely full or completely empty. Par compact " 669 "also has a smaller default value; see arguments.cpp."); 670 FLAG_RANGE( MarkSweepDeadRatio, 0, 100); 671 672 PRODUCT_FLAG(uint, MarkSweepAlwaysCompactCount, 4, JVMFlag::RANGE, 673 "How often should we fully compact the heap (ignoring the dead " 674 "space parameters)"); 675 FLAG_RANGE( MarkSweepAlwaysCompactCount, 1, max_juint); 676 677 DEVELOP_FLAG(uintx, GCExpandToAllocateDelayMillis, 0, JVMFlag::DEFAULT, 678 "Delay between expansion and allocation (in milliseconds)"); 679 680 PRODUCT_FLAG(uintx, GCDrainStackTargetSize, 64, JVMFlag::RANGE, 681 "Number of entries we will try to leave on the stack " 682 "during parallel gc"); 683 FLAG_RANGE( GCDrainStackTargetSize, 0, max_juint); 684 685 #endif // SHARE_GC_SHARED_GC_GLOBALS_HPP