1 /* 2 * Copyright (c) 1997, 2018, 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 "utilities/macros.hpp" 29 #if INCLUDE_CMSGC 30 #include "gc/cms/cms_globals.hpp" 31 #endif 32 #if INCLUDE_EPSILONGC 33 #include "gc/epsilon/epsilon_globals.hpp" 34 #endif 35 #if INCLUDE_G1GC 36 #include "gc/g1/g1_globals.hpp" 37 #endif 38 #if INCLUDE_PARALLELGC 39 #include "gc/parallel/parallel_globals.hpp" 40 #endif 41 #if INCLUDE_SERIALGC 42 #include "gc/serial/serial_globals.hpp" 43 #endif 44 #if INCLUDE_SHENANDOAHGC 45 #include "gc/shenandoah/shenandoah_globals.hpp" 46 #endif 47 #if INCLUDE_ZGC 48 #include "gc/z/z_globals.hpp" 49 #endif 50 51 #define GC_FLAGS(develop, \ 52 develop_pd, \ 53 product, \ 54 product_pd, \ 55 diagnostic, \ 56 diagnostic_pd, \ 57 experimental, \ 58 notproduct, \ 59 manageable, \ 60 product_rw, \ 61 lp64_product, \ 62 range, \ 63 constraint, \ 64 writeable) \ 65 \ 66 CMSGC_ONLY(GC_CMS_FLAGS( \ 67 develop, \ 68 develop_pd, \ 69 product, \ 70 product_pd, \ 71 diagnostic, \ 72 diagnostic_pd, \ 73 experimental, \ 74 notproduct, \ 75 manageable, \ 76 product_rw, \ 77 lp64_product, \ 78 range, \ 79 constraint, \ 80 writeable)) \ 81 \ 82 EPSILONGC_ONLY(GC_EPSILON_FLAGS( \ 83 develop, \ 84 develop_pd, \ 85 product, \ 86 product_pd, \ 87 diagnostic, \ 88 diagnostic_pd, \ 89 experimental, \ 90 notproduct, \ 91 manageable, \ 92 product_rw, \ 93 lp64_product, \ 94 range, \ 95 constraint, \ 96 writeable)) \ 97 \ 98 G1GC_ONLY(GC_G1_FLAGS( \ 99 develop, \ 100 develop_pd, \ 101 product, \ 102 product_pd, \ 103 diagnostic, \ 104 diagnostic_pd, \ 105 experimental, \ 106 notproduct, \ 107 manageable, \ 108 product_rw, \ 109 lp64_product, \ 110 range, \ 111 constraint, \ 112 writeable)) \ 113 \ 114 PARALLELGC_ONLY(GC_PARALLEL_FLAGS( \ 115 develop, \ 116 develop_pd, \ 117 product, \ 118 product_pd, \ 119 diagnostic, \ 120 diagnostic_pd, \ 121 experimental, \ 122 notproduct, \ 123 manageable, \ 124 product_rw, \ 125 lp64_product, \ 126 range, \ 127 constraint, \ 128 writeable)) \ 129 \ 130 SERIALGC_ONLY(GC_SERIAL_FLAGS( \ 131 develop, \ 132 develop_pd, \ 133 product, \ 134 product_pd, \ 135 diagnostic, \ 136 diagnostic_pd, \ 137 experimental, \ 138 notproduct, \ 139 manageable, \ 140 product_rw, \ 141 lp64_product, \ 142 range, \ 143 constraint, \ 144 writeable)) \ 145 \ 146 SHENANDOAHGC_ONLY(GC_SHENANDOAH_FLAGS( \ 147 develop, \ 148 develop_pd, \ 149 product, \ 150 product_pd, \ 151 diagnostic, \ 152 diagnostic_pd, \ 153 experimental, \ 154 notproduct, \ 155 manageable, \ 156 product_rw, \ 157 lp64_product, \ 158 range, \ 159 constraint, \ 160 writeable)) \ 161 \ 162 ZGC_ONLY(GC_Z_FLAGS( \ 163 develop, \ 164 develop_pd, \ 165 product, \ 166 product_pd, \ 167 diagnostic, \ 168 diagnostic_pd, \ 169 experimental, \ 170 notproduct, \ 171 manageable, \ 172 product_rw, \ 173 lp64_product, \ 174 range, \ 175 constraint, \ 176 writeable)) \ 177 \ 178 /* gc */ \ 179 \ 180 product(bool, UseConcMarkSweepGC, false, \ 181 "Use Concurrent Mark-Sweep GC in the old generation") \ 182 \ 183 product(bool, UseSerialGC, false, \ 184 "Use the Serial garbage collector") \ 185 \ 186 product(bool, UseG1GC, false, \ 187 "Use the Garbage-First garbage collector") \ 188 \ 189 product(bool, UseParallelGC, false, \ 190 "Use the Parallel Scavenge garbage collector") \ 191 \ 192 product(bool, UseParallelOldGC, false, \ 193 "Use the Parallel Old garbage collector") \ 194 \ 195 experimental(bool, UseEpsilonGC, false, \ 196 "Use the Epsilon (no-op) garbage collector") \ 197 \ 198 experimental(bool, UseZGC, false, \ 199 "Use the Z garbage collector") \ 200 \ 201 experimental(bool, UseShenandoahGC, false, \ 202 "Use the Shenandoah garbage collector") \ 203 \ 204 product(uint, ParallelGCThreads, 0, \ 205 "Number of parallel threads parallel gc will use") \ 206 constraint(ParallelGCThreadsConstraintFunc,AfterErgo) \ 207 \ 208 diagnostic(bool, UseSemaphoreGCThreadsSynchronization, true, \ 209 "Use semaphore synchronization for the GC Threads, " \ 210 "instead of synchronization based on mutexes") \ 211 \ 212 product(bool, UseDynamicNumberOfGCThreads, true, \ 213 "Dynamically choose the number of threads up to a maximum of " \ 214 "ParallelGCThreads parallel collectors will use for garbage " \ 215 "collection work") \ 216 \ 217 diagnostic(bool, InjectGCWorkerCreationFailure, false, \ 218 "Inject thread creation failures for " \ 219 "UseDynamicNumberOfGCThreads") \ 220 \ 221 diagnostic(bool, ForceDynamicNumberOfGCThreads, false, \ 222 "Force dynamic selection of the number of " \ 223 "parallel threads parallel gc will use to aid debugging") \ 224 \ 225 product(size_t, HeapSizePerGCThread, ScaleForWordSize(32*M), \ 226 "Size of heap (bytes) per GC thread used in calculating the " \ 227 "number of GC threads") \ 228 range((size_t)os::vm_page_size(), (size_t)max_uintx) \ 229 \ 230 product(uint, ConcGCThreads, 0, \ 231 "Number of threads concurrent gc will use") \ 232 constraint(ConcGCThreadsConstraintFunc,AfterErgo) \ 233 \ 234 product(uint, GCTaskTimeStampEntries, 200, \ 235 "Number of time stamp entries per gc worker thread") \ 236 range(1, max_jint) \ 237 \ 238 product(bool, AlwaysTenure, false, \ 239 "Always tenure objects in eden (ParallelGC only)") \ 240 \ 241 product(bool, NeverTenure, false, \ 242 "Never tenure objects in eden, may tenure on overflow " \ 243 "(ParallelGC only)") \ 244 \ 245 product(bool, ScavengeBeforeFullGC, true, \ 246 "Scavenge youngest generation before each full GC.") \ 247 \ 248 product(bool, ExplicitGCInvokesConcurrent, false, \ 249 "A System.gc() request invokes a concurrent collection; " \ 250 "(effective only when using concurrent collectors)") \ 251 \ 252 product(bool, GCLockerInvokesConcurrent, false, \ 253 "The exit of a JNI critical section necessitating a scavenge, " \ 254 "also kicks off a background concurrent collection") \ 255 \ 256 product(uintx, GCLockerEdenExpansionPercent, 5, \ 257 "How much the GC can expand the eden by while the GC locker " \ 258 "is active (as a percentage)") \ 259 range(0, 100) \ 260 \ 261 diagnostic(uintx, GCLockerRetryAllocationCount, 2, \ 262 "Number of times to retry allocations when " \ 263 "blocked by the GC locker") \ 264 range(0, max_uintx) \ 265 \ 266 product(uintx, ParallelGCBufferWastePct, 10, \ 267 "Wasted fraction of parallel allocation buffer") \ 268 range(0, 100) \ 269 \ 270 product(uintx, TargetPLABWastePct, 10, \ 271 "Target wasted space in last buffer as percent of overall " \ 272 "allocation") \ 273 range(1, 100) \ 274 \ 275 product(uintx, PLABWeight, 75, \ 276 "Percentage (0-100) used to weight the current sample when " \ 277 "computing exponentially decaying average for ResizePLAB") \ 278 range(0, 100) \ 279 \ 280 product(bool, ResizePLAB, true, \ 281 "Dynamically resize (survivor space) promotion LAB's") \ 282 \ 283 product(int, ParGCArrayScanChunk, 50, \ 284 "Scan a subset of object array and push remainder, if array is " \ 285 "bigger than this") \ 286 range(1, max_jint/3) \ 287 \ 288 product(uintx, OldPLABWeight, 50, \ 289 "Percentage (0-100) used to weight the current sample when " \ 290 "computing exponentially decaying average for resizing " \ 291 "OldPLABSize") \ 292 range(0, 100) \ 293 \ 294 product(bool, ResizeOldPLAB, true, \ 295 "Dynamically resize (old gen) promotion LAB's") \ 296 \ 297 product(bool, AlwaysPreTouch, false, \ 298 "Force all freshly committed pages to be pre-touched") \ 299 \ 300 product(size_t, PreTouchParallelChunkSize, 1 * G, \ 301 "Per-thread chunk size for parallel memory pre-touch.") \ 302 range(1, SIZE_MAX / 2) \ 303 \ 304 /* where does the range max value of (max_jint - 1) come from? */ \ 305 product(size_t, MarkStackSizeMax, NOT_LP64(4*M) LP64_ONLY(512*M), \ 306 "Maximum size of marking stack") \ 307 range(1, (max_jint - 1)) \ 308 \ 309 product(size_t, MarkStackSize, NOT_LP64(32*K) LP64_ONLY(4*M), \ 310 "Size of marking stack") \ 311 constraint(MarkStackSizeConstraintFunc,AfterErgo) \ 312 \ 313 develop(bool, VerifyBlockOffsetArray, false, \ 314 "Do (expensive) block offset array verification") \ 315 \ 316 diagnostic(bool, BlockOffsetArrayUseUnallocatedBlock, false, \ 317 "Maintain _unallocated_block in BlockOffsetArray " \ 318 "(currently applicable only to CMS collector)") \ 319 \ 320 product(intx, RefDiscoveryPolicy, 0, \ 321 "Select type of reference discovery policy: " \ 322 "reference-based(0) or referent-based(1)") \ 323 range(ReferenceProcessor::DiscoveryPolicyMin, \ 324 ReferenceProcessor::DiscoveryPolicyMax) \ 325 \ 326 product(bool, ParallelRefProcEnabled, false, \ 327 "Enable parallel reference processing whenever possible") \ 328 \ 329 product(bool, ParallelRefProcBalancingEnabled, true, \ 330 "Enable balancing of reference processing queues") \ 331 \ 332 experimental(size_t, ReferencesPerThread, 1000, \ 333 "Ergonomically start one thread for this amount of " \ 334 "references for reference processing if " \ 335 "ParallelRefProcEnabled is true. Specify 0 to disable and " \ 336 "use all threads.") \ 337 \ 338 product(uintx, InitiatingHeapOccupancyPercent, 45, \ 339 "The percent occupancy (IHOP) of the current old generation " \ 340 "capacity above which a concurrent mark cycle will be initiated " \ 341 "Its value may change over time if adaptive IHOP is enabled, " \ 342 "otherwise the value remains constant. " \ 343 "In the latter case a value of 0 will result as frequent as " \ 344 "possible concurrent marking cycles. A value of 100 disables " \ 345 "concurrent marking. " \ 346 "Fragmentation waste in the old generation is not considered " \ 347 "free space in this calculation. (G1 collector only)") \ 348 range(0, 100) \ 349 \ 350 notproduct(bool, ScavengeALot, false, \ 351 "Force scavenge at every Nth exit from the runtime system " \ 352 "(N=ScavengeALotInterval)") \ 353 \ 354 develop(bool, FullGCALot, false, \ 355 "Force full gc at every Nth exit from the runtime system " \ 356 "(N=FullGCALotInterval)") \ 357 \ 358 notproduct(bool, GCALotAtAllSafepoints, false, \ 359 "Enforce ScavengeALot/GCALot at all potential safepoints") \ 360 \ 361 notproduct(bool, PromotionFailureALot, false, \ 362 "Use promotion failure handling on every youngest generation " \ 363 "collection") \ 364 \ 365 develop(uintx, PromotionFailureALotCount, 1000, \ 366 "Number of promotion failures occurring at PLAB " \ 367 "refill attempts (ParNew) or promotion attempts " \ 368 "(other young collectors)") \ 369 \ 370 develop(uintx, PromotionFailureALotInterval, 5, \ 371 "Total collections between promotion failures a lot") \ 372 \ 373 experimental(uintx, WorkStealingSleepMillis, 1, \ 374 "Sleep time when sleep is used for yields") \ 375 \ 376 experimental(uintx, WorkStealingYieldsBeforeSleep, 5000, \ 377 "Number of yields before a sleep is done during work stealing") \ 378 \ 379 experimental(uintx, WorkStealingHardSpins, 4096, \ 380 "Number of iterations in a spin loop between checks on " \ 381 "time out of hard spin") \ 382 \ 383 experimental(uintx, WorkStealingSpinToYieldRatio, 10, \ 384 "Ratio of hard spins to calls to yield") \ 385 \ 386 develop(uintx, ObjArrayMarkingStride, 2048, \ 387 "Number of object array elements to push onto the marking stack " \ 388 "before pushing a continuation entry") \ 389 \ 390 develop(bool, MetadataAllocationFailALot, false, \ 391 "Fail metadata allocations at intervals controlled by " \ 392 "MetadataAllocationFailALotInterval") \ 393 \ 394 develop(uintx, MetadataAllocationFailALotInterval, 1000, \ 395 "Metadata allocation failure a lot interval") \ 396 \ 397 notproduct(bool, ExecuteInternalVMTests, false, \ 398 "Enable execution of internal VM tests") \ 399 \ 400 notproduct(bool, VerboseInternalVMTests, false, \ 401 "Turn on logging for internal VM tests.") \ 402 \ 403 product(bool, ExecutingUnitTests, false, \ 404 "Whether the JVM is running unit tests or not") \ 405 \ 406 product_pd(bool, UseTLAB, "Use thread-local object allocation") \ 407 \ 408 product_pd(bool, ResizeTLAB, \ 409 "Dynamically resize TLAB size for threads") \ 410 \ 411 product(bool, ZeroTLAB, false, \ 412 "Zero out the newly created TLAB") \ 413 \ 414 product(bool, TLABStats, true, \ 415 "Provide more detailed and expensive TLAB statistics.") \ 416 \ 417 product_pd(bool, NeverActAsServerClassMachine, \ 418 "Never act like a server-class machine") \ 419 \ 420 product(bool, AlwaysActAsServerClassMachine, false, \ 421 "Always act like a server-class machine") \ 422 \ 423 product_pd(uint64_t, MaxRAM, \ 424 "Real memory size (in bytes) used to set maximum heap size") \ 425 range(0, 0XFFFFFFFFFFFFFFFF) \ 426 \ 427 product(bool, AggressiveHeap, false, \ 428 "Optimize heap options for long-running memory intensive apps") \ 429 \ 430 product(size_t, ErgoHeapSizeLimit, 0, \ 431 "Maximum ergonomically set heap size (in bytes); zero means use " \ 432 "MaxRAM * MaxRAMPercentage / 100") \ 433 range(0, max_uintx) \ 434 \ 435 product(uintx, MaxRAMFraction, 4, \ 436 "Maximum fraction (1/n) of real memory used for maximum heap " \ 437 "size. " \ 438 "Deprecated, use MaxRAMPercentage instead") \ 439 range(1, max_uintx) \ 440 \ 441 product(uintx, MinRAMFraction, 2, \ 442 "Minimum fraction (1/n) of real memory used for maximum heap " \ 443 "size on systems with small physical memory size. " \ 444 "Deprecated, use MinRAMPercentage instead") \ 445 range(1, max_uintx) \ 446 \ 447 product(uintx, InitialRAMFraction, 64, \ 448 "Fraction (1/n) of real memory used for initial heap size. " \ 449 "Deprecated, use InitialRAMPercentage instead") \ 450 range(1, max_uintx) \ 451 \ 452 product(double, MaxRAMPercentage, 25.0, \ 453 "Maximum percentage of real memory used for maximum heap size") \ 454 range(0.0, 100.0) \ 455 \ 456 product(double, MinRAMPercentage, 50.0, \ 457 "Minimum percentage of real memory used for maximum heap" \ 458 "size on systems with small physical memory size") \ 459 range(0.0, 100.0) \ 460 \ 461 product(double, InitialRAMPercentage, 1.5625, \ 462 "Percentage of real memory used for initial heap size") \ 463 range(0.0, 100.0) \ 464 \ 465 product(int, ActiveProcessorCount, -1, \ 466 "Specify the CPU count the VM should use and report as active") \ 467 \ 468 develop(uintx, MaxVirtMemFraction, 2, \ 469 "Maximum fraction (1/n) of virtual memory used for ergonomically "\ 470 "determining maximum heap size") \ 471 \ 472 product(bool, UseAdaptiveSizePolicy, true, \ 473 "Use adaptive generation sizing policies") \ 474 \ 475 product(bool, UsePSAdaptiveSurvivorSizePolicy, true, \ 476 "Use adaptive survivor sizing policies") \ 477 \ 478 product(bool, UseAdaptiveGenerationSizePolicyAtMinorCollection, true, \ 479 "Use adaptive young-old sizing policies at minor collections") \ 480 \ 481 product(bool, UseAdaptiveGenerationSizePolicyAtMajorCollection, true, \ 482 "Use adaptive young-old sizing policies at major collections") \ 483 \ 484 product(bool, UseAdaptiveSizePolicyWithSystemGC, false, \ 485 "Include statistics from System.gc() for adaptive size policy") \ 486 \ 487 product(bool, UseAdaptiveGCBoundary, false, \ 488 "Allow young-old boundary to move") \ 489 \ 490 develop(intx, PSAdaptiveSizePolicyResizeVirtualSpaceAlot, -1, \ 491 "Resize the virtual spaces of the young or old generations") \ 492 range(-1, 1) \ 493 \ 494 product(uintx, AdaptiveSizeThroughPutPolicy, 0, \ 495 "Policy for changing generation size for throughput goals") \ 496 range(0, 1) \ 497 \ 498 product(uintx, AdaptiveSizePolicyInitializingSteps, 20, \ 499 "Number of steps where heuristics is used before data is used") \ 500 range(0, max_uintx) \ 501 \ 502 develop(uintx, AdaptiveSizePolicyReadyThreshold, 5, \ 503 "Number of collections before the adaptive sizing is started") \ 504 \ 505 product(uintx, AdaptiveSizePolicyOutputInterval, 0, \ 506 "Collection interval for printing information; zero means never") \ 507 range(0, max_uintx) \ 508 \ 509 product(bool, UseAdaptiveSizePolicyFootprintGoal, true, \ 510 "Use adaptive minimum footprint as a goal") \ 511 \ 512 product(uintx, AdaptiveSizePolicyWeight, 10, \ 513 "Weight given to exponential resizing, between 0 and 100") \ 514 range(0, 100) \ 515 \ 516 product(uintx, AdaptiveTimeWeight, 25, \ 517 "Weight given to time in adaptive policy, between 0 and 100") \ 518 range(0, 100) \ 519 \ 520 product(uintx, PausePadding, 1, \ 521 "How much buffer to keep for pause time") \ 522 range(0, max_juint) \ 523 \ 524 product(uintx, PromotedPadding, 3, \ 525 "How much buffer to keep for promotion failure") \ 526 range(0, max_juint) \ 527 \ 528 product(uintx, SurvivorPadding, 3, \ 529 "How much buffer to keep for survivor overflow") \ 530 range(0, max_juint) \ 531 \ 532 product(uintx, ThresholdTolerance, 10, \ 533 "Allowed collection cost difference between generations") \ 534 range(0, 100) \ 535 \ 536 product(uintx, AdaptiveSizePolicyCollectionCostMargin, 50, \ 537 "If collection costs are within margin, reduce both by full " \ 538 "delta") \ 539 range(0, 100) \ 540 \ 541 product(uintx, YoungGenerationSizeIncrement, 20, \ 542 "Adaptive size percentage change in young generation") \ 543 range(0, 100) \ 544 \ 545 product(uintx, YoungGenerationSizeSupplement, 80, \ 546 "Supplement to YoungedGenerationSizeIncrement used at startup") \ 547 range(0, 100) \ 548 \ 549 product(uintx, YoungGenerationSizeSupplementDecay, 8, \ 550 "Decay factor to YoungedGenerationSizeSupplement") \ 551 range(1, max_uintx) \ 552 \ 553 product(uintx, TenuredGenerationSizeIncrement, 20, \ 554 "Adaptive size percentage change in tenured generation") \ 555 range(0, 100) \ 556 \ 557 product(uintx, TenuredGenerationSizeSupplement, 80, \ 558 "Supplement to TenuredGenerationSizeIncrement used at startup") \ 559 range(0, 100) \ 560 \ 561 product(uintx, TenuredGenerationSizeSupplementDecay, 2, \ 562 "Decay factor to TenuredGenerationSizeIncrement") \ 563 range(1, max_uintx) \ 564 \ 565 product(uintx, MaxGCPauseMillis, max_uintx - 1, \ 566 "Adaptive size policy maximum GC pause time goal in millisecond, "\ 567 "or (G1 Only) the maximum GC time per MMU time slice") \ 568 range(1, max_uintx - 1) \ 569 constraint(MaxGCPauseMillisConstraintFunc,AfterErgo) \ 570 \ 571 product(uintx, GCPauseIntervalMillis, 0, \ 572 "Time slice for MMU specification") \ 573 constraint(GCPauseIntervalMillisConstraintFunc,AfterErgo) \ 574 \ 575 product(uintx, MaxGCMinorPauseMillis, max_uintx, \ 576 "Adaptive size policy maximum GC minor pause time goal " \ 577 "in millisecond") \ 578 range(0, max_uintx) \ 579 \ 580 product(uintx, GCTimeRatio, 99, \ 581 "Adaptive size policy application time to GC time ratio") \ 582 range(0, max_juint) \ 583 \ 584 product(uintx, AdaptiveSizeDecrementScaleFactor, 4, \ 585 "Adaptive size scale down factor for shrinking") \ 586 range(1, max_uintx) \ 587 \ 588 product(bool, UseAdaptiveSizeDecayMajorGCCost, true, \ 589 "Adaptive size decays the major cost for long major intervals") \ 590 \ 591 product(uintx, AdaptiveSizeMajorGCDecayTimeScale, 10, \ 592 "Time scale over which major costs decay") \ 593 range(0, max_uintx) \ 594 \ 595 product(uintx, MinSurvivorRatio, 3, \ 596 "Minimum ratio of young generation/survivor space size") \ 597 range(3, max_uintx) \ 598 \ 599 product(uintx, InitialSurvivorRatio, 8, \ 600 "Initial ratio of young generation/survivor space size") \ 601 range(0, max_uintx) \ 602 \ 603 product(size_t, BaseFootPrintEstimate, 256*M, \ 604 "Estimate of footprint other than Java Heap") \ 605 range(0, max_uintx) \ 606 \ 607 product(bool, UseGCOverheadLimit, true, \ 608 "Use policy to limit of proportion of time spent in GC " \ 609 "before an OutOfMemory error is thrown") \ 610 \ 611 product(uintx, GCTimeLimit, 98, \ 612 "Limit of the proportion of time spent in GC before " \ 613 "an OutOfMemoryError is thrown (used with GCHeapFreeLimit)") \ 614 range(0, 100) \ 615 \ 616 product(uintx, GCHeapFreeLimit, 2, \ 617 "Minimum percentage of free space after a full GC before an " \ 618 "OutOfMemoryError is thrown (used with GCTimeLimit)") \ 619 range(0, 100) \ 620 \ 621 develop(uintx, AdaptiveSizePolicyGCTimeLimitThreshold, 5, \ 622 "Number of consecutive collections before gc time limit fires") \ 623 range(1, max_uintx) \ 624 \ 625 product(intx, PrefetchCopyIntervalInBytes, -1, \ 626 "How far ahead to prefetch destination area (<= 0 means off)") \ 627 range(-1, max_jint) \ 628 \ 629 product(intx, PrefetchScanIntervalInBytes, -1, \ 630 "How far ahead to prefetch scan area (<= 0 means off)") \ 631 range(-1, max_jint) \ 632 \ 633 product(intx, PrefetchFieldsAhead, -1, \ 634 "How many fields ahead to prefetch in oop scan (<= 0 means off)") \ 635 range(-1, max_jint) \ 636 \ 637 diagnostic(bool, VerifyDuringStartup, false, \ 638 "Verify memory system before executing any Java code " \ 639 "during VM initialization") \ 640 \ 641 diagnostic(bool, VerifyBeforeExit, trueInDebug, \ 642 "Verify system before exiting") \ 643 \ 644 diagnostic(bool, VerifyBeforeGC, false, \ 645 "Verify memory system before GC") \ 646 \ 647 diagnostic(bool, VerifyAfterGC, false, \ 648 "Verify memory system after GC") \ 649 \ 650 diagnostic(bool, VerifyDuringGC, false, \ 651 "Verify memory system during GC (between phases)") \ 652 \ 653 diagnostic(ccstrlist, VerifyGCType, "", \ 654 "GC type(s) to verify when Verify*GC is enabled." \ 655 "Available types are collector specific.") \ 656 \ 657 diagnostic(ccstrlist, VerifySubSet, "", \ 658 "Memory sub-systems to verify when Verify*GC flag(s) " \ 659 "are enabled. One or more sub-systems can be specified " \ 660 "in a comma separated string. Sub-systems are: " \ 661 "threads, heap, symbol_table, string_table, codecache, " \ 662 "dictionary, classloader_data_graph, metaspace, jni_handles, " \ 663 "codecache_oops") \ 664 \ 665 diagnostic(bool, GCParallelVerificationEnabled, true, \ 666 "Enable parallel memory system verification") \ 667 \ 668 diagnostic(bool, DeferInitialCardMark, false, \ 669 "When +ReduceInitialCardMarks, explicitly defer any that " \ 670 "may arise from new_pre_store_barrier") \ 671 \ 672 product(bool, UseCondCardMark, false, \ 673 "Check for already marked card before updating card table") \ 674 \ 675 diagnostic(bool, VerifyRememberedSets, false, \ 676 "Verify GC remembered sets") \ 677 \ 678 diagnostic(bool, VerifyObjectStartArray, true, \ 679 "Verify GC object start array if verify before/after") \ 680 \ 681 product(bool, DisableExplicitGC, false, \ 682 "Ignore calls to System.gc()") \ 683 \ 684 product(bool, BindGCTaskThreadsToCPUs, false, \ 685 "Bind GCTaskThreads to CPUs if possible") \ 686 \ 687 product(bool, UseGCTaskAffinity, false, \ 688 "Use worker affinity when asking for GCTasks") \ 689 \ 690 product(bool, PrintGC, false, \ 691 "Print message at garbage collection. " \ 692 "Deprecated, use -Xlog:gc instead.") \ 693 \ 694 product(bool, PrintGCDetails, false, \ 695 "Print more details at garbage collection. " \ 696 "Deprecated, use -Xlog:gc* instead.") \ 697 \ 698 develop(intx, ConcGCYieldTimeout, 0, \ 699 "If non-zero, assert that GC threads yield within this " \ 700 "number of milliseconds") \ 701 range(0, max_intx) \ 702 \ 703 notproduct(intx, ScavengeALotInterval, 1, \ 704 "Interval between which scavenge will occur with +ScavengeALot") \ 705 \ 706 notproduct(intx, FullGCALotInterval, 1, \ 707 "Interval between which full gc will occur with +FullGCALot") \ 708 \ 709 notproduct(intx, FullGCALotStart, 0, \ 710 "For which invocation to start FullGCAlot") \ 711 \ 712 notproduct(intx, FullGCALotDummies, 32*K, \ 713 "Dummy object allocated with +FullGCALot, forcing all objects " \ 714 "to move") \ 715 \ 716 /* gc parameters */ \ 717 product(size_t, InitialHeapSize, 0, \ 718 "Initial heap size (in bytes); zero means use ergonomics") \ 719 constraint(InitialHeapSizeConstraintFunc,AfterErgo) \ 720 \ 721 product(size_t, MaxHeapSize, ScaleForWordSize(96*M), \ 722 "Maximum heap size (in bytes)") \ 723 constraint(MaxHeapSizeConstraintFunc,AfterErgo) \ 724 \ 725 product(size_t, OldSize, ScaleForWordSize(4*M), \ 726 "Initial tenured generation size (in bytes)") \ 727 range(0, max_uintx) \ 728 \ 729 product(size_t, NewSize, ScaleForWordSize(1*M), \ 730 "Initial new generation size (in bytes)") \ 731 constraint(NewSizeConstraintFunc,AfterErgo) \ 732 \ 733 product(size_t, MaxNewSize, max_uintx, \ 734 "Maximum new generation size (in bytes), max_uintx means set " \ 735 "ergonomically") \ 736 range(0, max_uintx) \ 737 \ 738 product_pd(size_t, HeapBaseMinAddress, \ 739 "OS specific low limit for heap base address") \ 740 constraint(HeapBaseMinAddressConstraintFunc,AfterErgo) \ 741 \ 742 product(size_t, PretenureSizeThreshold, 0, \ 743 "Maximum size in bytes of objects allocated in DefNew " \ 744 "generation; zero means no maximum") \ 745 range(0, max_uintx) \ 746 \ 747 product(size_t, MinTLABSize, 2*K, \ 748 "Minimum allowed TLAB size (in bytes)") \ 749 range(1, max_uintx/2) \ 750 constraint(MinTLABSizeConstraintFunc,AfterMemoryInit) \ 751 \ 752 product(size_t, TLABSize, 0, \ 753 "Starting TLAB size (in bytes); zero means set ergonomically") \ 754 constraint(TLABSizeConstraintFunc,AfterMemoryInit) \ 755 \ 756 product(size_t, YoungPLABSize, 4096, \ 757 "Size of young gen promotion LAB's (in HeapWords)") \ 758 constraint(YoungPLABSizeConstraintFunc,AfterMemoryInit) \ 759 \ 760 product(size_t, OldPLABSize, 1024, \ 761 "Size of old gen promotion LAB's (in HeapWords), or Number " \ 762 "of blocks to attempt to claim when refilling CMS LAB's") \ 763 constraint(OldPLABSizeConstraintFunc,AfterMemoryInit) \ 764 \ 765 product(uintx, TLABAllocationWeight, 35, \ 766 "Allocation averaging weight") \ 767 range(0, 100) \ 768 \ 769 /* Limit the lower bound of this flag to 1 as it is used */ \ 770 /* in a division expression. */ \ 771 product(uintx, TLABWasteTargetPercent, 1, \ 772 "Percentage of Eden that can be wasted") \ 773 range(1, 100) \ 774 \ 775 product(uintx, TLABRefillWasteFraction, 64, \ 776 "Maximum TLAB waste at a refill (internal fragmentation)") \ 777 range(1, max_juint) \ 778 \ 779 product(uintx, TLABWasteIncrement, 4, \ 780 "Increment allowed waste at slow allocation") \ 781 range(0, max_jint) \ 782 constraint(TLABWasteIncrementConstraintFunc,AfterMemoryInit) \ 783 \ 784 product(uintx, SurvivorRatio, 8, \ 785 "Ratio of eden/survivor space size") \ 786 range(1, max_uintx-2) \ 787 constraint(SurvivorRatioConstraintFunc,AfterMemoryInit) \ 788 \ 789 product(uintx, NewRatio, 2, \ 790 "Ratio of old/new generation sizes") \ 791 range(0, max_uintx-1) \ 792 \ 793 product_pd(size_t, NewSizeThreadIncrease, \ 794 "Additional size added to desired new generation size per " \ 795 "non-daemon thread (in bytes)") \ 796 range(0, max_uintx) \ 797 \ 798 product(uintx, QueuedAllocationWarningCount, 0, \ 799 "Number of times an allocation that queues behind a GC " \ 800 "will retry before printing a warning") \ 801 range(0, max_uintx) \ 802 \ 803 diagnostic(uintx, VerifyGCStartAt, 0, \ 804 "GC invoke count where +VerifyBefore/AfterGC kicks in") \ 805 range(0, max_uintx) \ 806 \ 807 diagnostic(intx, VerifyGCLevel, 0, \ 808 "Generation level at which to start +VerifyBefore/AfterGC") \ 809 range(0, 1) \ 810 \ 811 product(uintx, MaxTenuringThreshold, 15, \ 812 "Maximum value for tenuring threshold") \ 813 range(0, markOopDesc::max_age + 1) \ 814 constraint(MaxTenuringThresholdConstraintFunc,AfterErgo) \ 815 \ 816 product(uintx, InitialTenuringThreshold, 7, \ 817 "Initial value for tenuring threshold") \ 818 range(0, markOopDesc::max_age + 1) \ 819 constraint(InitialTenuringThresholdConstraintFunc,AfterErgo) \ 820 \ 821 product(uintx, TargetSurvivorRatio, 50, \ 822 "Desired percentage of survivor space used after scavenge") \ 823 range(0, 100) \ 824 \ 825 product(uintx, MarkSweepDeadRatio, 5, \ 826 "Percentage (0-100) of the old gen allowed as dead wood. " \ 827 "Serial mark sweep treats this as both the minimum and maximum " \ 828 "value. " \ 829 "CMS uses this value only if it falls back to mark sweep. " \ 830 "Par compact uses a variable scale based on the density of the " \ 831 "generation and treats this as the maximum value when the heap " \ 832 "is either completely full or completely empty. Par compact " \ 833 "also has a smaller default value; see arguments.cpp.") \ 834 range(0, 100) \ 835 \ 836 product(uint, MarkSweepAlwaysCompactCount, 4, \ 837 "How often should we fully compact the heap (ignoring the dead " \ 838 "space parameters)") \ 839 range(1, max_juint) \ 840 \ 841 develop(uintx, GCExpandToAllocateDelayMillis, 0, \ 842 "Delay between expansion and allocation (in milliseconds)") \ 843 \ 844 product(uintx, GCDrainStackTargetSize, 64, \ 845 "Number of entries we will try to leave on the stack " \ 846 "during parallel gc") \ 847 range(0, max_juint) 848 849 #endif // SHARE_GC_SHARED_GC_GLOBALS_HPP