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 #if INCLUDE_SHENANDOAHGC 52 #define shproduct(product, type, name, value, doc) product(type, name, value, doc) 53 #else 54 #define shproduct(product, type, name, value, doc) 55 #endif 56 57 #define GC_FLAGS(develop, \ 58 develop_pd, \ 59 product, \ 60 product_pd, \ 61 diagnostic, \ 62 diagnostic_pd, \ 63 experimental, \ 64 notproduct, \ 65 manageable, \ 66 product_rw, \ 67 lp64_product, \ 68 range, \ 69 constraint, \ 70 writeable) \ 71 \ 72 CMSGC_ONLY(GC_CMS_FLAGS( \ 73 develop, \ 74 develop_pd, \ 75 product, \ 76 product_pd, \ 77 diagnostic, \ 78 diagnostic_pd, \ 79 experimental, \ 80 notproduct, \ 81 manageable, \ 82 product_rw, \ 83 lp64_product, \ 84 range, \ 85 constraint, \ 86 writeable)) \ 87 \ 88 EPSILONGC_ONLY(GC_EPSILON_FLAGS( \ 89 develop, \ 90 develop_pd, \ 91 product, \ 92 product_pd, \ 93 diagnostic, \ 94 diagnostic_pd, \ 95 experimental, \ 96 notproduct, \ 97 manageable, \ 98 product_rw, \ 99 lp64_product, \ 100 range, \ 101 constraint, \ 102 writeable)) \ 103 \ 104 G1GC_ONLY(GC_G1_FLAGS( \ 105 develop, \ 106 develop_pd, \ 107 product, \ 108 product_pd, \ 109 diagnostic, \ 110 diagnostic_pd, \ 111 experimental, \ 112 notproduct, \ 113 manageable, \ 114 product_rw, \ 115 lp64_product, \ 116 range, \ 117 constraint, \ 118 writeable)) \ 119 \ 120 PARALLELGC_ONLY(GC_PARALLEL_FLAGS( \ 121 develop, \ 122 develop_pd, \ 123 product, \ 124 product_pd, \ 125 diagnostic, \ 126 diagnostic_pd, \ 127 experimental, \ 128 notproduct, \ 129 manageable, \ 130 product_rw, \ 131 lp64_product, \ 132 range, \ 133 constraint, \ 134 writeable)) \ 135 \ 136 SERIALGC_ONLY(GC_SERIAL_FLAGS( \ 137 develop, \ 138 develop_pd, \ 139 product, \ 140 product_pd, \ 141 diagnostic, \ 142 diagnostic_pd, \ 143 experimental, \ 144 notproduct, \ 145 manageable, \ 146 product_rw, \ 147 lp64_product, \ 148 range, \ 149 constraint, \ 150 writeable)) \ 151 \ 152 SHENANDOAHGC_ONLY(GC_SHENANDOAH_FLAGS( \ 153 develop, \ 154 develop_pd, \ 155 product, \ 156 product_pd, \ 157 diagnostic, \ 158 diagnostic_pd, \ 159 experimental, \ 160 notproduct, \ 161 manageable, \ 162 product_rw, \ 163 lp64_product, \ 164 range, \ 165 constraint, \ 166 writeable)) \ 167 \ 168 ZGC_ONLY(GC_Z_FLAGS( \ 169 develop, \ 170 develop_pd, \ 171 product, \ 172 product_pd, \ 173 diagnostic, \ 174 diagnostic_pd, \ 175 experimental, \ 176 notproduct, \ 177 manageable, \ 178 product_rw, \ 179 lp64_product, \ 180 range, \ 181 constraint, \ 182 writeable)) \ 183 \ 184 /* gc */ \ 185 \ 186 product(bool, UseConcMarkSweepGC, false, \ 187 "Use Concurrent Mark-Sweep GC in the old generation") \ 188 \ 189 product(bool, UseSerialGC, false, \ 190 "Use the Serial garbage collector") \ 191 \ 192 product(bool, UseG1GC, false, \ 193 "Use the Garbage-First garbage collector") \ 194 \ 195 product(bool, UseParallelGC, false, \ 196 "Use the Parallel Scavenge garbage collector") \ 197 \ 198 product(bool, UseParallelOldGC, false, \ 199 "Use the Parallel Old garbage collector") \ 200 \ 201 experimental(bool, UseEpsilonGC, false, \ 202 "Use the Epsilon (no-op) garbage collector") \ 203 \ 204 experimental(bool, UseZGC, false, \ 205 "Use the Z garbage collector") \ 206 \ 207 shproduct(product, bool, UseShenandoahGC, false, \ 208 "Use the Shenandoah garbage collector") \ 209 \ 210 product(uint, ParallelGCThreads, 0, \ 211 "Number of parallel threads parallel gc will use") \ 212 constraint(ParallelGCThreadsConstraintFunc,AfterErgo) \ 213 \ 214 diagnostic(bool, UseSemaphoreGCThreadsSynchronization, true, \ 215 "Use semaphore synchronization for the GC Threads, " \ 216 "instead of synchronization based on mutexes") \ 217 \ 218 product(bool, UseDynamicNumberOfGCThreads, true, \ 219 "Dynamically choose the number of threads up to a maximum of " \ 220 "ParallelGCThreads parallel collectors will use for garbage " \ 221 "collection work") \ 222 \ 223 diagnostic(bool, InjectGCWorkerCreationFailure, false, \ 224 "Inject thread creation failures for " \ 225 "UseDynamicNumberOfGCThreads") \ 226 \ 227 diagnostic(bool, ForceDynamicNumberOfGCThreads, false, \ 228 "Force dynamic selection of the number of " \ 229 "parallel threads parallel gc will use to aid debugging") \ 230 \ 231 product(size_t, HeapSizePerGCThread, ScaleForWordSize(32*M), \ 232 "Size of heap (bytes) per GC thread used in calculating the " \ 233 "number of GC threads") \ 234 range((size_t)os::vm_page_size(), (size_t)max_uintx) \ 235 \ 236 product(uint, ConcGCThreads, 0, \ 237 "Number of threads concurrent gc will use") \ 238 constraint(ConcGCThreadsConstraintFunc,AfterErgo) \ 239 \ 240 product(uint, GCTaskTimeStampEntries, 200, \ 241 "Number of time stamp entries per gc worker thread") \ 242 range(1, max_jint) \ 243 \ 244 product(bool, AlwaysTenure, false, \ 245 "Always tenure objects in eden (ParallelGC only)") \ 246 \ 247 product(bool, NeverTenure, false, \ 248 "Never tenure objects in eden, may tenure on overflow " \ 249 "(ParallelGC only)") \ 250 \ 251 product(bool, ScavengeBeforeFullGC, true, \ 252 "Scavenge youngest generation before each full GC.") \ 253 \ 254 product(bool, ExplicitGCInvokesConcurrent, false, \ 255 "A System.gc() request invokes a concurrent collection; " \ 256 "(effective only when using concurrent collectors)") \ 257 \ 258 product(bool, GCLockerInvokesConcurrent, false, \ 259 "The exit of a JNI critical section necessitating a scavenge, " \ 260 "also kicks off a background concurrent collection") \ 261 \ 262 product(uintx, GCLockerEdenExpansionPercent, 5, \ 263 "How much the GC can expand the eden by while the GC locker " \ 264 "is active (as a percentage)") \ 265 range(0, 100) \ 266 \ 267 diagnostic(uintx, GCLockerRetryAllocationCount, 2, \ 268 "Number of times to retry allocations when " \ 269 "blocked by the GC locker") \ 270 range(0, max_uintx) \ 271 \ 272 product(uintx, ParallelGCBufferWastePct, 10, \ 273 "Wasted fraction of parallel allocation buffer") \ 274 range(0, 100) \ 275 \ 276 product(uintx, TargetPLABWastePct, 10, \ 277 "Target wasted space in last buffer as percent of overall " \ 278 "allocation") \ 279 range(1, 100) \ 280 \ 281 product(uintx, PLABWeight, 75, \ 282 "Percentage (0-100) used to weight the current sample when " \ 283 "computing exponentially decaying average for ResizePLAB") \ 284 range(0, 100) \ 285 \ 286 product(bool, ResizePLAB, true, \ 287 "Dynamically resize (survivor space) promotion LAB's") \ 288 \ 289 product(int, ParGCArrayScanChunk, 50, \ 290 "Scan a subset of object array and push remainder, if array is " \ 291 "bigger than this") \ 292 range(1, max_jint/3) \ 293 \ 294 product(uintx, OldPLABWeight, 50, \ 295 "Percentage (0-100) used to weight the current sample when " \ 296 "computing exponentially decaying average for resizing " \ 297 "OldPLABSize") \ 298 range(0, 100) \ 299 \ 300 product(bool, ResizeOldPLAB, true, \ 301 "Dynamically resize (old gen) promotion LAB's") \ 302 \ 303 product(bool, AlwaysPreTouch, false, \ 304 "Force all freshly committed pages to be pre-touched") \ 305 \ 306 product(size_t, PreTouchParallelChunkSize, 1 * G, \ 307 "Per-thread chunk size for parallel memory pre-touch.") \ 308 range(1, SIZE_MAX / 2) \ 309 \ 310 /* where does the range max value of (max_jint - 1) come from? */ \ 311 product(size_t, MarkStackSizeMax, NOT_LP64(4*M) LP64_ONLY(512*M), \ 312 "Maximum size of marking stack") \ 313 range(1, (max_jint - 1)) \ 314 \ 315 product(size_t, MarkStackSize, NOT_LP64(32*K) LP64_ONLY(4*M), \ 316 "Size of marking stack") \ 317 constraint(MarkStackSizeConstraintFunc,AfterErgo) \ 318 \ 319 develop(bool, VerifyBlockOffsetArray, false, \ 320 "Do (expensive) block offset array verification") \ 321 \ 322 diagnostic(bool, BlockOffsetArrayUseUnallocatedBlock, false, \ 323 "Maintain _unallocated_block in BlockOffsetArray " \ 324 "(currently applicable only to CMS collector)") \ 325 \ 326 product(intx, RefDiscoveryPolicy, 0, \ 327 "Select type of reference discovery policy: " \ 328 "reference-based(0) or referent-based(1)") \ 329 range(ReferenceProcessor::DiscoveryPolicyMin, \ 330 ReferenceProcessor::DiscoveryPolicyMax) \ 331 \ 332 product(bool, ParallelRefProcEnabled, false, \ 333 "Enable parallel reference processing whenever possible") \ 334 \ 335 product(bool, ParallelRefProcBalancingEnabled, true, \ 336 "Enable balancing of reference processing queues") \ 337 \ 338 experimental(size_t, ReferencesPerThread, 1000, \ 339 "Ergonomically start one thread for this amount of " \ 340 "references for reference processing if " \ 341 "ParallelRefProcEnabled is true. Specify 0 to disable and " \ 342 "use all threads.") \ 343 \ 344 product(uintx, InitiatingHeapOccupancyPercent, 45, \ 345 "The percent occupancy (IHOP) of the current old generation " \ 346 "capacity above which a concurrent mark cycle will be initiated " \ 347 "Its value may change over time if adaptive IHOP is enabled, " \ 348 "otherwise the value remains constant. " \ 349 "In the latter case a value of 0 will result as frequent as " \ 350 "possible concurrent marking cycles. A value of 100 disables " \ 351 "concurrent marking. " \ 352 "Fragmentation waste in the old generation is not considered " \ 353 "free space in this calculation. (G1 collector only)") \ 354 range(0, 100) \ 355 \ 356 notproduct(bool, ScavengeALot, false, \ 357 "Force scavenge at every Nth exit from the runtime system " \ 358 "(N=ScavengeALotInterval)") \ 359 \ 360 develop(bool, FullGCALot, false, \ 361 "Force full gc at every Nth exit from the runtime system " \ 362 "(N=FullGCALotInterval)") \ 363 \ 364 notproduct(bool, GCALotAtAllSafepoints, false, \ 365 "Enforce ScavengeALot/GCALot at all potential safepoints") \ 366 \ 367 notproduct(bool, PromotionFailureALot, false, \ 368 "Use promotion failure handling on every youngest generation " \ 369 "collection") \ 370 \ 371 develop(uintx, PromotionFailureALotCount, 1000, \ 372 "Number of promotion failures occurring at PLAB " \ 373 "refill attempts (ParNew) or promotion attempts " \ 374 "(other young collectors)") \ 375 \ 376 develop(uintx, PromotionFailureALotInterval, 5, \ 377 "Total collections between promotion failures a lot") \ 378 \ 379 experimental(uintx, WorkStealingSleepMillis, 1, \ 380 "Sleep time when sleep is used for yields") \ 381 \ 382 experimental(uintx, WorkStealingYieldsBeforeSleep, 5000, \ 383 "Number of yields before a sleep is done during work stealing") \ 384 \ 385 experimental(uintx, WorkStealingHardSpins, 4096, \ 386 "Number of iterations in a spin loop between checks on " \ 387 "time out of hard spin") \ 388 \ 389 experimental(uintx, WorkStealingSpinToYieldRatio, 10, \ 390 "Ratio of hard spins to calls to yield") \ 391 \ 392 develop(uintx, ObjArrayMarkingStride, 2048, \ 393 "Number of object array elements to push onto the marking stack " \ 394 "before pushing a continuation entry") \ 395 \ 396 develop(bool, MetadataAllocationFailALot, false, \ 397 "Fail metadata allocations at intervals controlled by " \ 398 "MetadataAllocationFailALotInterval") \ 399 \ 400 develop(uintx, MetadataAllocationFailALotInterval, 1000, \ 401 "Metadata allocation failure a lot interval") \ 402 \ 403 notproduct(bool, ExecuteInternalVMTests, false, \ 404 "Enable execution of internal VM tests") \ 405 \ 406 notproduct(bool, VerboseInternalVMTests, false, \ 407 "Turn on logging for internal VM tests.") \ 408 \ 409 product(bool, ExecutingUnitTests, false, \ 410 "Whether the JVM is running unit tests or not") \ 411 \ 412 product_pd(bool, UseTLAB, "Use thread-local object allocation") \ 413 \ 414 product_pd(bool, ResizeTLAB, \ 415 "Dynamically resize TLAB size for threads") \ 416 \ 417 product(bool, ZeroTLAB, false, \ 418 "Zero out the newly created TLAB") \ 419 \ 420 product(bool, TLABStats, true, \ 421 "Provide more detailed and expensive TLAB statistics.") \ 422 \ 423 product_pd(bool, NeverActAsServerClassMachine, \ 424 "Never act like a server-class machine") \ 425 \ 426 product(bool, AlwaysActAsServerClassMachine, false, \ 427 "Always act like a server-class machine") \ 428 \ 429 product_pd(uint64_t, MaxRAM, \ 430 "Real memory size (in bytes) used to set maximum heap size") \ 431 range(0, 0XFFFFFFFFFFFFFFFF) \ 432 \ 433 product(bool, AggressiveHeap, false, \ 434 "Optimize heap options for long-running memory intensive apps") \ 435 \ 436 product(size_t, ErgoHeapSizeLimit, 0, \ 437 "Maximum ergonomically set heap size (in bytes); zero means use " \ 438 "MaxRAM * MaxRAMPercentage / 100") \ 439 range(0, max_uintx) \ 440 \ 441 product(uintx, MaxRAMFraction, 4, \ 442 "Maximum fraction (1/n) of real memory used for maximum heap " \ 443 "size. " \ 444 "Deprecated, use MaxRAMPercentage instead") \ 445 range(1, max_uintx) \ 446 \ 447 product(uintx, MinRAMFraction, 2, \ 448 "Minimum fraction (1/n) of real memory used for maximum heap " \ 449 "size on systems with small physical memory size. " \ 450 "Deprecated, use MinRAMPercentage instead") \ 451 range(1, max_uintx) \ 452 \ 453 product(uintx, InitialRAMFraction, 64, \ 454 "Fraction (1/n) of real memory used for initial heap size. " \ 455 "Deprecated, use InitialRAMPercentage instead") \ 456 range(1, max_uintx) \ 457 \ 458 product(double, MaxRAMPercentage, 25.0, \ 459 "Maximum percentage of real memory used for maximum heap size") \ 460 range(0.0, 100.0) \ 461 \ 462 product(double, MinRAMPercentage, 50.0, \ 463 "Minimum percentage of real memory used for maximum heap" \ 464 "size on systems with small physical memory size") \ 465 range(0.0, 100.0) \ 466 \ 467 product(double, InitialRAMPercentage, 1.5625, \ 468 "Percentage of real memory used for initial heap size") \ 469 range(0.0, 100.0) \ 470 \ 471 product(int, ActiveProcessorCount, -1, \ 472 "Specify the CPU count the VM should use and report as active") \ 473 \ 474 develop(uintx, MaxVirtMemFraction, 2, \ 475 "Maximum fraction (1/n) of virtual memory used for ergonomically "\ 476 "determining maximum heap size") \ 477 \ 478 product(bool, UseAdaptiveSizePolicy, true, \ 479 "Use adaptive generation sizing policies") \ 480 \ 481 product(bool, UsePSAdaptiveSurvivorSizePolicy, true, \ 482 "Use adaptive survivor sizing policies") \ 483 \ 484 product(bool, UseAdaptiveGenerationSizePolicyAtMinorCollection, true, \ 485 "Use adaptive young-old sizing policies at minor collections") \ 486 \ 487 product(bool, UseAdaptiveGenerationSizePolicyAtMajorCollection, true, \ 488 "Use adaptive young-old sizing policies at major collections") \ 489 \ 490 product(bool, UseAdaptiveSizePolicyWithSystemGC, false, \ 491 "Include statistics from System.gc() for adaptive size policy") \ 492 \ 493 product(bool, UseAdaptiveGCBoundary, false, \ 494 "Allow young-old boundary to move") \ 495 \ 496 develop(intx, PSAdaptiveSizePolicyResizeVirtualSpaceAlot, -1, \ 497 "Resize the virtual spaces of the young or old generations") \ 498 range(-1, 1) \ 499 \ 500 product(uintx, AdaptiveSizeThroughPutPolicy, 0, \ 501 "Policy for changing generation size for throughput goals") \ 502 range(0, 1) \ 503 \ 504 product(uintx, AdaptiveSizePolicyInitializingSteps, 20, \ 505 "Number of steps where heuristics is used before data is used") \ 506 range(0, max_uintx) \ 507 \ 508 develop(uintx, AdaptiveSizePolicyReadyThreshold, 5, \ 509 "Number of collections before the adaptive sizing is started") \ 510 \ 511 product(uintx, AdaptiveSizePolicyOutputInterval, 0, \ 512 "Collection interval for printing information; zero means never") \ 513 range(0, max_uintx) \ 514 \ 515 product(bool, UseAdaptiveSizePolicyFootprintGoal, true, \ 516 "Use adaptive minimum footprint as a goal") \ 517 \ 518 product(uintx, AdaptiveSizePolicyWeight, 10, \ 519 "Weight given to exponential resizing, between 0 and 100") \ 520 range(0, 100) \ 521 \ 522 product(uintx, AdaptiveTimeWeight, 25, \ 523 "Weight given to time in adaptive policy, between 0 and 100") \ 524 range(0, 100) \ 525 \ 526 product(uintx, PausePadding, 1, \ 527 "How much buffer to keep for pause time") \ 528 range(0, max_juint) \ 529 \ 530 product(uintx, PromotedPadding, 3, \ 531 "How much buffer to keep for promotion failure") \ 532 range(0, max_juint) \ 533 \ 534 product(uintx, SurvivorPadding, 3, \ 535 "How much buffer to keep for survivor overflow") \ 536 range(0, max_juint) \ 537 \ 538 product(uintx, ThresholdTolerance, 10, \ 539 "Allowed collection cost difference between generations") \ 540 range(0, 100) \ 541 \ 542 product(uintx, AdaptiveSizePolicyCollectionCostMargin, 50, \ 543 "If collection costs are within margin, reduce both by full " \ 544 "delta") \ 545 range(0, 100) \ 546 \ 547 product(uintx, YoungGenerationSizeIncrement, 20, \ 548 "Adaptive size percentage change in young generation") \ 549 range(0, 100) \ 550 \ 551 product(uintx, YoungGenerationSizeSupplement, 80, \ 552 "Supplement to YoungedGenerationSizeIncrement used at startup") \ 553 range(0, 100) \ 554 \ 555 product(uintx, YoungGenerationSizeSupplementDecay, 8, \ 556 "Decay factor to YoungedGenerationSizeSupplement") \ 557 range(1, max_uintx) \ 558 \ 559 product(uintx, TenuredGenerationSizeIncrement, 20, \ 560 "Adaptive size percentage change in tenured generation") \ 561 range(0, 100) \ 562 \ 563 product(uintx, TenuredGenerationSizeSupplement, 80, \ 564 "Supplement to TenuredGenerationSizeIncrement used at startup") \ 565 range(0, 100) \ 566 \ 567 product(uintx, TenuredGenerationSizeSupplementDecay, 2, \ 568 "Decay factor to TenuredGenerationSizeIncrement") \ 569 range(1, max_uintx) \ 570 \ 571 product(uintx, MaxGCPauseMillis, max_uintx - 1, \ 572 "Adaptive size policy maximum GC pause time goal in millisecond, "\ 573 "or (G1 Only) the maximum GC time per MMU time slice") \ 574 range(1, max_uintx - 1) \ 575 constraint(MaxGCPauseMillisConstraintFunc,AfterErgo) \ 576 \ 577 product(uintx, GCPauseIntervalMillis, 0, \ 578 "Time slice for MMU specification") \ 579 constraint(GCPauseIntervalMillisConstraintFunc,AfterErgo) \ 580 \ 581 product(uintx, MaxGCMinorPauseMillis, max_uintx, \ 582 "Adaptive size policy maximum GC minor pause time goal " \ 583 "in millisecond") \ 584 range(0, max_uintx) \ 585 \ 586 product(uintx, GCTimeRatio, 99, \ 587 "Adaptive size policy application time to GC time ratio") \ 588 range(0, max_juint) \ 589 \ 590 product(uintx, AdaptiveSizeDecrementScaleFactor, 4, \ 591 "Adaptive size scale down factor for shrinking") \ 592 range(1, max_uintx) \ 593 \ 594 product(bool, UseAdaptiveSizeDecayMajorGCCost, true, \ 595 "Adaptive size decays the major cost for long major intervals") \ 596 \ 597 product(uintx, AdaptiveSizeMajorGCDecayTimeScale, 10, \ 598 "Time scale over which major costs decay") \ 599 range(0, max_uintx) \ 600 \ 601 product(uintx, MinSurvivorRatio, 3, \ 602 "Minimum ratio of young generation/survivor space size") \ 603 range(3, max_uintx) \ 604 \ 605 product(uintx, InitialSurvivorRatio, 8, \ 606 "Initial ratio of young generation/survivor space size") \ 607 range(0, max_uintx) \ 608 \ 609 product(size_t, BaseFootPrintEstimate, 256*M, \ 610 "Estimate of footprint other than Java Heap") \ 611 range(0, max_uintx) \ 612 \ 613 product(bool, UseGCOverheadLimit, true, \ 614 "Use policy to limit of proportion of time spent in GC " \ 615 "before an OutOfMemory error is thrown") \ 616 \ 617 product(uintx, GCTimeLimit, 98, \ 618 "Limit of the proportion of time spent in GC before " \ 619 "an OutOfMemoryError is thrown (used with GCHeapFreeLimit)") \ 620 range(0, 100) \ 621 \ 622 product(uintx, GCHeapFreeLimit, 2, \ 623 "Minimum percentage of free space after a full GC before an " \ 624 "OutOfMemoryError is thrown (used with GCTimeLimit)") \ 625 range(0, 100) \ 626 \ 627 develop(uintx, AdaptiveSizePolicyGCTimeLimitThreshold, 5, \ 628 "Number of consecutive collections before gc time limit fires") \ 629 range(1, max_uintx) \ 630 \ 631 product(intx, PrefetchCopyIntervalInBytes, -1, \ 632 "How far ahead to prefetch destination area (<= 0 means off)") \ 633 range(-1, max_jint) \ 634 \ 635 product(intx, PrefetchScanIntervalInBytes, -1, \ 636 "How far ahead to prefetch scan area (<= 0 means off)") \ 637 range(-1, max_jint) \ 638 \ 639 product(intx, PrefetchFieldsAhead, -1, \ 640 "How many fields ahead to prefetch in oop scan (<= 0 means off)") \ 641 range(-1, max_jint) \ 642 \ 643 diagnostic(bool, VerifyDuringStartup, false, \ 644 "Verify memory system before executing any Java code " \ 645 "during VM initialization") \ 646 \ 647 diagnostic(bool, VerifyBeforeExit, trueInDebug, \ 648 "Verify system before exiting") \ 649 \ 650 diagnostic(bool, VerifyBeforeGC, false, \ 651 "Verify memory system before GC") \ 652 \ 653 diagnostic(bool, VerifyAfterGC, false, \ 654 "Verify memory system after GC") \ 655 \ 656 diagnostic(bool, VerifyDuringGC, false, \ 657 "Verify memory system during GC (between phases)") \ 658 \ 659 diagnostic(ccstrlist, VerifyGCType, "", \ 660 "GC type(s) to verify when Verify*GC is enabled." \ 661 "Available types are collector specific.") \ 662 \ 663 diagnostic(ccstrlist, VerifySubSet, "", \ 664 "Memory sub-systems to verify when Verify*GC flag(s) " \ 665 "are enabled. One or more sub-systems can be specified " \ 666 "in a comma separated string. Sub-systems are: " \ 667 "threads, heap, symbol_table, string_table, codecache, " \ 668 "dictionary, classloader_data_graph, metaspace, jni_handles, " \ 669 "codecache_oops") \ 670 \ 671 diagnostic(bool, GCParallelVerificationEnabled, true, \ 672 "Enable parallel memory system verification") \ 673 \ 674 diagnostic(bool, DeferInitialCardMark, false, \ 675 "When +ReduceInitialCardMarks, explicitly defer any that " \ 676 "may arise from new_pre_store_barrier") \ 677 \ 678 product(bool, UseCondCardMark, false, \ 679 "Check for already marked card before updating card table") \ 680 \ 681 diagnostic(bool, VerifyRememberedSets, false, \ 682 "Verify GC remembered sets") \ 683 \ 684 diagnostic(bool, VerifyObjectStartArray, true, \ 685 "Verify GC object start array if verify before/after") \ 686 \ 687 product(bool, DisableExplicitGC, false, \ 688 "Ignore calls to System.gc()") \ 689 \ 690 product(bool, BindGCTaskThreadsToCPUs, false, \ 691 "Bind GCTaskThreads to CPUs if possible") \ 692 \ 693 product(bool, UseGCTaskAffinity, false, \ 694 "Use worker affinity when asking for GCTasks") \ 695 \ 696 product(bool, PrintGC, false, \ 697 "Print message at garbage collection. " \ 698 "Deprecated, use -Xlog:gc instead.") \ 699 \ 700 product(bool, PrintGCDetails, false, \ 701 "Print more details at garbage collection. " \ 702 "Deprecated, use -Xlog:gc* instead.") \ 703 \ 704 develop(intx, ConcGCYieldTimeout, 0, \ 705 "If non-zero, assert that GC threads yield within this " \ 706 "number of milliseconds") \ 707 range(0, max_intx) \ 708 \ 709 notproduct(intx, ScavengeALotInterval, 1, \ 710 "Interval between which scavenge will occur with +ScavengeALot") \ 711 \ 712 notproduct(intx, FullGCALotInterval, 1, \ 713 "Interval between which full gc will occur with +FullGCALot") \ 714 \ 715 notproduct(intx, FullGCALotStart, 0, \ 716 "For which invocation to start FullGCAlot") \ 717 \ 718 notproduct(intx, FullGCALotDummies, 32*K, \ 719 "Dummy object allocated with +FullGCALot, forcing all objects " \ 720 "to move") \ 721 \ 722 /* gc parameters */ \ 723 product(size_t, InitialHeapSize, 0, \ 724 "Initial heap size (in bytes); zero means use ergonomics") \ 725 constraint(InitialHeapSizeConstraintFunc,AfterErgo) \ 726 \ 727 product(size_t, MaxHeapSize, ScaleForWordSize(96*M), \ 728 "Maximum heap size (in bytes)") \ 729 constraint(MaxHeapSizeConstraintFunc,AfterErgo) \ 730 \ 731 product(size_t, OldSize, ScaleForWordSize(4*M), \ 732 "Initial tenured generation size (in bytes)") \ 733 range(0, max_uintx) \ 734 \ 735 product(size_t, NewSize, ScaleForWordSize(1*M), \ 736 "Initial new generation size (in bytes)") \ 737 constraint(NewSizeConstraintFunc,AfterErgo) \ 738 \ 739 product(size_t, MaxNewSize, max_uintx, \ 740 "Maximum new generation size (in bytes), max_uintx means set " \ 741 "ergonomically") \ 742 range(0, max_uintx) \ 743 \ 744 product_pd(size_t, HeapBaseMinAddress, \ 745 "OS specific low limit for heap base address") \ 746 constraint(HeapBaseMinAddressConstraintFunc,AfterErgo) \ 747 \ 748 product(size_t, PretenureSizeThreshold, 0, \ 749 "Maximum size in bytes of objects allocated in DefNew " \ 750 "generation; zero means no maximum") \ 751 range(0, max_uintx) \ 752 \ 753 product(size_t, MinTLABSize, 2*K, \ 754 "Minimum allowed TLAB size (in bytes)") \ 755 range(1, max_uintx/2) \ 756 constraint(MinTLABSizeConstraintFunc,AfterMemoryInit) \ 757 \ 758 product(size_t, TLABSize, 0, \ 759 "Starting TLAB size (in bytes); zero means set ergonomically") \ 760 constraint(TLABSizeConstraintFunc,AfterMemoryInit) \ 761 \ 762 product(size_t, YoungPLABSize, 4096, \ 763 "Size of young gen promotion LAB's (in HeapWords)") \ 764 constraint(YoungPLABSizeConstraintFunc,AfterMemoryInit) \ 765 \ 766 product(size_t, OldPLABSize, 1024, \ 767 "Size of old gen promotion LAB's (in HeapWords), or Number " \ 768 "of blocks to attempt to claim when refilling CMS LAB's") \ 769 constraint(OldPLABSizeConstraintFunc,AfterMemoryInit) \ 770 \ 771 product(uintx, TLABAllocationWeight, 35, \ 772 "Allocation averaging weight") \ 773 range(0, 100) \ 774 \ 775 /* Limit the lower bound of this flag to 1 as it is used */ \ 776 /* in a division expression. */ \ 777 product(uintx, TLABWasteTargetPercent, 1, \ 778 "Percentage of Eden that can be wasted") \ 779 range(1, 100) \ 780 \ 781 product(uintx, TLABRefillWasteFraction, 64, \ 782 "Maximum TLAB waste at a refill (internal fragmentation)") \ 783 range(1, max_juint) \ 784 \ 785 product(uintx, TLABWasteIncrement, 4, \ 786 "Increment allowed waste at slow allocation") \ 787 range(0, max_jint) \ 788 constraint(TLABWasteIncrementConstraintFunc,AfterMemoryInit) \ 789 \ 790 product(uintx, SurvivorRatio, 8, \ 791 "Ratio of eden/survivor space size") \ 792 range(1, max_uintx-2) \ 793 constraint(SurvivorRatioConstraintFunc,AfterMemoryInit) \ 794 \ 795 product(uintx, NewRatio, 2, \ 796 "Ratio of old/new generation sizes") \ 797 range(0, max_uintx-1) \ 798 \ 799 product_pd(size_t, NewSizeThreadIncrease, \ 800 "Additional size added to desired new generation size per " \ 801 "non-daemon thread (in bytes)") \ 802 range(0, max_uintx) \ 803 \ 804 product(uintx, QueuedAllocationWarningCount, 0, \ 805 "Number of times an allocation that queues behind a GC " \ 806 "will retry before printing a warning") \ 807 range(0, max_uintx) \ 808 \ 809 diagnostic(uintx, VerifyGCStartAt, 0, \ 810 "GC invoke count where +VerifyBefore/AfterGC kicks in") \ 811 range(0, max_uintx) \ 812 \ 813 diagnostic(intx, VerifyGCLevel, 0, \ 814 "Generation level at which to start +VerifyBefore/AfterGC") \ 815 range(0, 1) \ 816 \ 817 product(uintx, MaxTenuringThreshold, 15, \ 818 "Maximum value for tenuring threshold") \ 819 range(0, markOopDesc::max_age + 1) \ 820 constraint(MaxTenuringThresholdConstraintFunc,AfterErgo) \ 821 \ 822 product(uintx, InitialTenuringThreshold, 7, \ 823 "Initial value for tenuring threshold") \ 824 range(0, markOopDesc::max_age + 1) \ 825 constraint(InitialTenuringThresholdConstraintFunc,AfterErgo) \ 826 \ 827 product(uintx, TargetSurvivorRatio, 50, \ 828 "Desired percentage of survivor space used after scavenge") \ 829 range(0, 100) \ 830 \ 831 product(uintx, MarkSweepDeadRatio, 5, \ 832 "Percentage (0-100) of the old gen allowed as dead wood. " \ 833 "Serial mark sweep treats this as both the minimum and maximum " \ 834 "value. " \ 835 "CMS uses this value only if it falls back to mark sweep. " \ 836 "Par compact uses a variable scale based on the density of the " \ 837 "generation and treats this as the maximum value when the heap " \ 838 "is either completely full or completely empty. Par compact " \ 839 "also has a smaller default value; see arguments.cpp.") \ 840 range(0, 100) \ 841 \ 842 product(uint, MarkSweepAlwaysCompactCount, 4, \ 843 "How often should we fully compact the heap (ignoring the dead " \ 844 "space parameters)") \ 845 range(1, max_juint) \ 846 \ 847 develop(uintx, GCExpandToAllocateDelayMillis, 0, \ 848 "Delay between expansion and allocation (in milliseconds)") \ 849 \ 850 product(uintx, GCDrainStackTargetSize, 64, \ 851 "Number of entries we will try to leave on the stack " \ 852 "during parallel gc") \ 853 range(0, max_juint) 854 855 #endif // SHARE_GC_SHARED_GC_GLOBALS_HPP 856