1 /* 2 * Copyright (c) 1997, 2019, 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_CMSGC 31 #include "gc/cms/cms_globals.hpp" 32 #endif 33 #if INCLUDE_EPSILONGC 34 #include "gc/epsilon/epsilon_globals.hpp" 35 #endif 36 #if INCLUDE_G1GC 37 #include "gc/g1/g1_globals.hpp" 38 #endif 39 #if INCLUDE_PARALLELGC 40 #include "gc/parallel/parallel_globals.hpp" 41 #endif 42 #if INCLUDE_SERIALGC 43 #include "gc/serial/serial_globals.hpp" 44 #endif 45 #if INCLUDE_SHENANDOAHGC 46 #include "gc/shenandoah/shenandoah_globals.hpp" 47 #endif 48 #if INCLUDE_ZGC 49 #include "gc/z/z_globals.hpp" 50 #endif 51 52 #define GC_FLAGS(develop, \ 53 develop_pd, \ 54 product, \ 55 product_pd, \ 56 diagnostic, \ 57 diagnostic_pd, \ 58 experimental, \ 59 notproduct, \ 60 manageable, \ 61 product_rw, \ 62 lp64_product, \ 63 range, \ 64 constraint, \ 65 writeable) \ 66 \ 67 CMSGC_ONLY(GC_CMS_FLAGS( \ 68 develop, \ 69 develop_pd, \ 70 product, \ 71 product_pd, \ 72 diagnostic, \ 73 diagnostic_pd, \ 74 experimental, \ 75 notproduct, \ 76 manageable, \ 77 product_rw, \ 78 lp64_product, \ 79 range, \ 80 constraint, \ 81 writeable)) \ 82 \ 83 EPSILONGC_ONLY(GC_EPSILON_FLAGS( \ 84 develop, \ 85 develop_pd, \ 86 product, \ 87 product_pd, \ 88 diagnostic, \ 89 diagnostic_pd, \ 90 experimental, \ 91 notproduct, \ 92 manageable, \ 93 product_rw, \ 94 lp64_product, \ 95 range, \ 96 constraint, \ 97 writeable)) \ 98 \ 99 G1GC_ONLY(GC_G1_FLAGS( \ 100 develop, \ 101 develop_pd, \ 102 product, \ 103 product_pd, \ 104 diagnostic, \ 105 diagnostic_pd, \ 106 experimental, \ 107 notproduct, \ 108 manageable, \ 109 product_rw, \ 110 lp64_product, \ 111 range, \ 112 constraint, \ 113 writeable)) \ 114 \ 115 PARALLELGC_ONLY(GC_PARALLEL_FLAGS( \ 116 develop, \ 117 develop_pd, \ 118 product, \ 119 product_pd, \ 120 diagnostic, \ 121 diagnostic_pd, \ 122 experimental, \ 123 notproduct, \ 124 manageable, \ 125 product_rw, \ 126 lp64_product, \ 127 range, \ 128 constraint, \ 129 writeable)) \ 130 \ 131 SERIALGC_ONLY(GC_SERIAL_FLAGS( \ 132 develop, \ 133 develop_pd, \ 134 product, \ 135 product_pd, \ 136 diagnostic, \ 137 diagnostic_pd, \ 138 experimental, \ 139 notproduct, \ 140 manageable, \ 141 product_rw, \ 142 lp64_product, \ 143 range, \ 144 constraint, \ 145 writeable)) \ 146 \ 147 SHENANDOAHGC_ONLY(GC_SHENANDOAH_FLAGS( \ 148 develop, \ 149 develop_pd, \ 150 product, \ 151 product_pd, \ 152 diagnostic, \ 153 diagnostic_pd, \ 154 experimental, \ 155 notproduct, \ 156 manageable, \ 157 product_rw, \ 158 lp64_product, \ 159 range, \ 160 constraint, \ 161 writeable)) \ 162 \ 163 ZGC_ONLY(GC_Z_FLAGS( \ 164 develop, \ 165 develop_pd, \ 166 product, \ 167 product_pd, \ 168 diagnostic, \ 169 diagnostic_pd, \ 170 experimental, \ 171 notproduct, \ 172 manageable, \ 173 product_rw, \ 174 lp64_product, \ 175 range, \ 176 constraint, \ 177 writeable)) \ 178 \ 179 /* gc */ \ 180 \ 181 product(bool, UseConcMarkSweepGC, false, \ 182 "Use Concurrent Mark-Sweep GC in the old generation") \ 183 \ 184 product(bool, UseSerialGC, false, \ 185 "Use the Serial garbage collector") \ 186 \ 187 product(bool, UseG1GC, false, \ 188 "Use the Garbage-First garbage collector") \ 189 \ 190 product(bool, UseParallelGC, false, \ 191 "Use the Parallel Scavenge garbage collector") \ 192 \ 193 product(bool, UseParallelOldGC, false, \ 194 "Use the Parallel Old garbage collector") \ 195 \ 196 experimental(bool, UseEpsilonGC, false, \ 197 "Use the Epsilon (no-op) garbage collector") \ 198 \ 199 experimental(bool, UseZGC, false, \ 200 "Use the Z garbage collector") \ 201 \ 202 experimental(bool, UseShenandoahGC, false, \ 203 "Use the Shenandoah garbage collector") \ 204 \ 205 product(uint, ParallelGCThreads, 0, \ 206 "Number of parallel threads parallel gc will use") \ 207 constraint(ParallelGCThreadsConstraintFunc,AfterErgo) \ 208 \ 209 diagnostic(bool, UseSemaphoreGCThreadsSynchronization, true, \ 210 "Use semaphore synchronization for the GC Threads, " \ 211 "instead of synchronization based on mutexes") \ 212 \ 213 product(bool, UseDynamicNumberOfGCThreads, true, \ 214 "Dynamically choose the number of threads up to a maximum of " \ 215 "ParallelGCThreads parallel collectors will use for garbage " \ 216 "collection work") \ 217 \ 218 diagnostic(bool, InjectGCWorkerCreationFailure, false, \ 219 "Inject thread creation failures for " \ 220 "UseDynamicNumberOfGCThreads") \ 221 \ 222 diagnostic(bool, ForceDynamicNumberOfGCThreads, false, \ 223 "Force dynamic selection of the number of " \ 224 "parallel threads parallel gc will use to aid debugging") \ 225 \ 226 product(size_t, HeapSizePerGCThread, ScaleForWordSize(32*M), \ 227 "Size of heap (bytes) per GC thread used in calculating the " \ 228 "number of GC threads") \ 229 range((size_t)os::vm_page_size(), (size_t)max_uintx) \ 230 \ 231 product(uint, ConcGCThreads, 0, \ 232 "Number of threads concurrent gc will use") \ 233 constraint(ConcGCThreadsConstraintFunc,AfterErgo) \ 234 \ 235 product(uint, GCTaskTimeStampEntries, 200, \ 236 "Number of time stamp entries per gc worker thread") \ 237 range(1, max_jint) \ 238 \ 239 product(bool, AlwaysTenure, false, \ 240 "Always tenure objects in eden (ParallelGC only)") \ 241 \ 242 product(bool, NeverTenure, false, \ 243 "Never tenure objects in eden, may tenure on overflow " \ 244 "(ParallelGC only)") \ 245 \ 246 product(bool, ScavengeBeforeFullGC, true, \ 247 "Scavenge youngest generation before each full GC.") \ 248 \ 249 product(bool, ExplicitGCInvokesConcurrent, false, \ 250 "A System.gc() request invokes a concurrent collection; " \ 251 "(effective only when using concurrent collectors)") \ 252 \ 253 product(bool, GCLockerInvokesConcurrent, false, \ 254 "The exit of a JNI critical section necessitating a scavenge, " \ 255 "also kicks off a background concurrent collection") \ 256 \ 257 product(uintx, GCLockerEdenExpansionPercent, 5, \ 258 "How much the GC can expand the eden by while the GC locker " \ 259 "is active (as a percentage)") \ 260 range(0, 100) \ 261 \ 262 diagnostic(uintx, GCLockerRetryAllocationCount, 2, \ 263 "Number of times to retry allocations when " \ 264 "blocked by the GC locker") \ 265 range(0, max_uintx) \ 266 \ 267 product(uintx, ParallelGCBufferWastePct, 10, \ 268 "Wasted fraction of parallel allocation buffer") \ 269 range(0, 100) \ 270 \ 271 product(uintx, TargetPLABWastePct, 10, \ 272 "Target wasted space in last buffer as percent of overall " \ 273 "allocation") \ 274 range(1, 100) \ 275 \ 276 product(uintx, PLABWeight, 75, \ 277 "Percentage (0-100) used to weight the current sample when " \ 278 "computing exponentially decaying average for ResizePLAB") \ 279 range(0, 100) \ 280 \ 281 product(bool, ResizePLAB, true, \ 282 "Dynamically resize (survivor space) promotion LAB's") \ 283 \ 284 product(int, ParGCArrayScanChunk, 50, \ 285 "Scan a subset of object array and push remainder, if array is " \ 286 "bigger than this") \ 287 range(1, max_jint/3) \ 288 \ 289 product(uintx, OldPLABWeight, 50, \ 290 "Percentage (0-100) used to weight the current sample when " \ 291 "computing exponentially decaying average for resizing " \ 292 "OldPLABSize") \ 293 range(0, 100) \ 294 \ 295 product(bool, ResizeOldPLAB, true, \ 296 "Dynamically resize (old gen) promotion LAB's") \ 297 \ 298 product(bool, AlwaysPreTouch, false, \ 299 "Force all freshly committed pages to be pre-touched") \ 300 \ 301 product(size_t, PreTouchParallelChunkSize, 1 * G, \ 302 "Per-thread chunk size for parallel memory pre-touch.") \ 303 range(1, SIZE_MAX / 2) \ 304 \ 305 /* where does the range max value of (max_jint - 1) come from? */ \ 306 product(size_t, MarkStackSizeMax, NOT_LP64(4*M) LP64_ONLY(512*M), \ 307 "Maximum size of marking stack") \ 308 range(1, (max_jint - 1)) \ 309 \ 310 product(size_t, MarkStackSize, NOT_LP64(32*K) LP64_ONLY(4*M), \ 311 "Size of marking stack") \ 312 constraint(MarkStackSizeConstraintFunc,AfterErgo) \ 313 \ 314 develop(bool, VerifyBlockOffsetArray, false, \ 315 "Do (expensive) block offset array verification") \ 316 \ 317 diagnostic(bool, BlockOffsetArrayUseUnallocatedBlock, false, \ 318 "Maintain _unallocated_block in BlockOffsetArray " \ 319 "(currently applicable only to CMS collector)") \ 320 \ 321 product(intx, RefDiscoveryPolicy, 0, \ 322 "Select type of reference discovery policy: " \ 323 "reference-based(0) or referent-based(1)") \ 324 range(ReferenceProcessor::DiscoveryPolicyMin, \ 325 ReferenceProcessor::DiscoveryPolicyMax) \ 326 \ 327 product(bool, ParallelRefProcEnabled, false, \ 328 "Enable parallel reference processing whenever possible") \ 329 \ 330 product(bool, ParallelRefProcBalancingEnabled, true, \ 331 "Enable balancing of reference processing queues") \ 332 \ 333 experimental(size_t, ReferencesPerThread, 1000, \ 334 "Ergonomically start one thread for this amount of " \ 335 "references for reference processing if " \ 336 "ParallelRefProcEnabled is true. Specify 0 to disable and " \ 337 "use all threads.") \ 338 \ 339 product(uintx, InitiatingHeapOccupancyPercent, 45, \ 340 "The percent occupancy (IHOP) of the current old generation " \ 341 "capacity above which a concurrent mark cycle will be initiated " \ 342 "Its value may change over time if adaptive IHOP is enabled, " \ 343 "otherwise the value remains constant. " \ 344 "In the latter case a value of 0 will result as frequent as " \ 345 "possible concurrent marking cycles. A value of 100 disables " \ 346 "concurrent marking. " \ 347 "Fragmentation waste in the old generation is not considered " \ 348 "free space in this calculation. (G1 collector only)") \ 349 range(0, 100) \ 350 \ 351 notproduct(bool, ScavengeALot, false, \ 352 "Force scavenge at every Nth exit from the runtime system " \ 353 "(N=ScavengeALotInterval)") \ 354 \ 355 develop(bool, FullGCALot, false, \ 356 "Force full gc at every Nth exit from the runtime system " \ 357 "(N=FullGCALotInterval)") \ 358 \ 359 notproduct(bool, GCALotAtAllSafepoints, false, \ 360 "Enforce ScavengeALot/GCALot at all potential safepoints") \ 361 \ 362 notproduct(bool, PromotionFailureALot, false, \ 363 "Use promotion failure handling on every youngest generation " \ 364 "collection") \ 365 \ 366 develop(uintx, PromotionFailureALotCount, 1000, \ 367 "Number of promotion failures occurring at PLAB " \ 368 "refill attempts (ParNew) or promotion attempts " \ 369 "(other young collectors)") \ 370 \ 371 develop(uintx, PromotionFailureALotInterval, 5, \ 372 "Total collections between promotion failures a lot") \ 373 \ 374 diagnostic(bool, UseOWSTTaskTerminator, true, \ 375 "Use Optimized Work Stealing Threads task termination " \ 376 "protocol") \ 377 \ 378 experimental(uintx, WorkStealingSleepMillis, 1, \ 379 "Sleep time when sleep is used for yields") \ 380 \ 381 experimental(uintx, WorkStealingYieldsBeforeSleep, 5000, \ 382 "Number of yields before a sleep is done during work stealing") \ 383 \ 384 experimental(uintx, WorkStealingHardSpins, 4096, \ 385 "Number of iterations in a spin loop between checks on " \ 386 "time out of hard spin") \ 387 \ 388 experimental(uintx, WorkStealingSpinToYieldRatio, 10, \ 389 "Ratio of hard spins to calls to yield") \ 390 \ 391 develop(uintx, ObjArrayMarkingStride, 2048, \ 392 "Number of object array elements to push onto the marking stack " \ 393 "before pushing a continuation entry") \ 394 \ 395 develop(bool, MetadataAllocationFailALot, false, \ 396 "Fail metadata allocations at intervals controlled by " \ 397 "MetadataAllocationFailALotInterval") \ 398 \ 399 develop(uintx, MetadataAllocationFailALotInterval, 1000, \ 400 "Metadata allocation failure a lot interval") \ 401 \ 402 product(bool, ExecutingUnitTests, false, \ 403 "Whether the JVM is running unit tests or not") \ 404 \ 405 product_pd(bool, UseTLAB, "Use thread-local object allocation") \ 406 \ 407 product_pd(bool, ResizeTLAB, \ 408 "Dynamically resize TLAB size for threads") \ 409 \ 410 product(bool, ZeroTLAB, false, \ 411 "Zero out the newly created TLAB") \ 412 \ 413 product(bool, TLABStats, true, \ 414 "Provide more detailed and expensive TLAB statistics.") \ 415 \ 416 product_pd(bool, NeverActAsServerClassMachine, \ 417 "Never act like a server-class machine") \ 418 \ 419 product(bool, AlwaysActAsServerClassMachine, false, \ 420 "Always act like a server-class machine") \ 421 \ 422 product_pd(uint64_t, MaxRAM, \ 423 "Real memory size (in bytes) used to set maximum heap size") \ 424 range(0, 0XFFFFFFFFFFFFFFFF) \ 425 \ 426 product(bool, AggressiveHeap, false, \ 427 "Optimize heap options for long-running memory intensive apps") \ 428 \ 429 product(size_t, ErgoHeapSizeLimit, 0, \ 430 "Maximum ergonomically set heap size (in bytes); zero means use " \ 431 "MaxRAM * MaxRAMPercentage / 100") \ 432 range(0, max_uintx) \ 433 \ 434 product(uintx, MaxRAMFraction, 4, \ 435 "Maximum fraction (1/n) of real memory used for maximum heap " \ 436 "size. " \ 437 "Deprecated, use MaxRAMPercentage instead") \ 438 range(1, max_uintx) \ 439 \ 440 product(uintx, MinRAMFraction, 2, \ 441 "Minimum fraction (1/n) of real memory used for maximum heap " \ 442 "size on systems with small physical memory size. " \ 443 "Deprecated, use MinRAMPercentage instead") \ 444 range(1, max_uintx) \ 445 \ 446 product(uintx, InitialRAMFraction, 64, \ 447 "Fraction (1/n) of real memory used for initial heap size. " \ 448 "Deprecated, use InitialRAMPercentage instead") \ 449 range(1, max_uintx) \ 450 \ 451 product(double, MaxRAMPercentage, 25.0, \ 452 "Maximum percentage of real memory used for maximum heap size") \ 453 range(0.0, 100.0) \ 454 \ 455 product(double, MinRAMPercentage, 50.0, \ 456 "Minimum percentage of real memory used for maximum heap" \ 457 "size on systems with small physical memory size") \ 458 range(0.0, 100.0) \ 459 \ 460 product(double, InitialRAMPercentage, 1.5625, \ 461 "Percentage of real memory used for initial heap size") \ 462 range(0.0, 100.0) \ 463 \ 464 product(int, ActiveProcessorCount, -1, \ 465 "Specify the CPU count the VM should use and report as active") \ 466 \ 467 develop(uintx, MaxVirtMemFraction, 2, \ 468 "Maximum fraction (1/n) of virtual memory used for ergonomically "\ 469 "determining maximum heap size") \ 470 \ 471 product(bool, UseAdaptiveSizePolicy, true, \ 472 "Use adaptive generation sizing policies") \ 473 \ 474 product(bool, UsePSAdaptiveSurvivorSizePolicy, true, \ 475 "Use adaptive survivor sizing policies") \ 476 \ 477 product(bool, UseAdaptiveGenerationSizePolicyAtMinorCollection, true, \ 478 "Use adaptive young-old sizing policies at minor collections") \ 479 \ 480 product(bool, UseAdaptiveGenerationSizePolicyAtMajorCollection, true, \ 481 "Use adaptive young-old sizing policies at major collections") \ 482 \ 483 product(bool, UseAdaptiveSizePolicyWithSystemGC, false, \ 484 "Include statistics from System.gc() for adaptive size policy") \ 485 \ 486 product(bool, UseAdaptiveGCBoundary, false, \ 487 "Allow young-old boundary to move") \ 488 \ 489 develop(intx, PSAdaptiveSizePolicyResizeVirtualSpaceAlot, -1, \ 490 "Resize the virtual spaces of the young or old generations") \ 491 range(-1, 1) \ 492 \ 493 product(uintx, AdaptiveSizeThroughPutPolicy, 0, \ 494 "Policy for changing generation size for throughput goals") \ 495 range(0, 1) \ 496 \ 497 product(uintx, AdaptiveSizePolicyInitializingSteps, 20, \ 498 "Number of steps where heuristics is used before data is used") \ 499 range(0, max_uintx) \ 500 \ 501 develop(uintx, AdaptiveSizePolicyReadyThreshold, 5, \ 502 "Number of collections before the adaptive sizing is started") \ 503 \ 504 product(uintx, AdaptiveSizePolicyOutputInterval, 0, \ 505 "Collection interval for printing information; zero means never") \ 506 range(0, max_uintx) \ 507 \ 508 product(bool, UseAdaptiveSizePolicyFootprintGoal, true, \ 509 "Use adaptive minimum footprint as a goal") \ 510 \ 511 product(uintx, AdaptiveSizePolicyWeight, 10, \ 512 "Weight given to exponential resizing, between 0 and 100") \ 513 range(0, 100) \ 514 \ 515 product(uintx, AdaptiveTimeWeight, 25, \ 516 "Weight given to time in adaptive policy, between 0 and 100") \ 517 range(0, 100) \ 518 \ 519 product(uintx, PausePadding, 1, \ 520 "How much buffer to keep for pause time") \ 521 range(0, max_juint) \ 522 \ 523 product(uintx, PromotedPadding, 3, \ 524 "How much buffer to keep for promotion failure") \ 525 range(0, max_juint) \ 526 \ 527 product(uintx, SurvivorPadding, 3, \ 528 "How much buffer to keep for survivor overflow") \ 529 range(0, max_juint) \ 530 \ 531 product(uintx, ThresholdTolerance, 10, \ 532 "Allowed collection cost difference between generations") \ 533 range(0, 100) \ 534 \ 535 product(uintx, AdaptiveSizePolicyCollectionCostMargin, 50, \ 536 "If collection costs are within margin, reduce both by full " \ 537 "delta") \ 538 range(0, 100) \ 539 \ 540 product(uintx, YoungGenerationSizeIncrement, 20, \ 541 "Adaptive size percentage change in young generation") \ 542 range(0, 100) \ 543 \ 544 product(uintx, YoungGenerationSizeSupplement, 80, \ 545 "Supplement to YoungedGenerationSizeIncrement used at startup") \ 546 range(0, 100) \ 547 \ 548 product(uintx, YoungGenerationSizeSupplementDecay, 8, \ 549 "Decay factor to YoungedGenerationSizeSupplement") \ 550 range(1, max_uintx) \ 551 \ 552 product(uintx, TenuredGenerationSizeIncrement, 20, \ 553 "Adaptive size percentage change in tenured generation") \ 554 range(0, 100) \ 555 \ 556 product(uintx, TenuredGenerationSizeSupplement, 80, \ 557 "Supplement to TenuredGenerationSizeIncrement used at startup") \ 558 range(0, 100) \ 559 \ 560 product(uintx, TenuredGenerationSizeSupplementDecay, 2, \ 561 "Decay factor to TenuredGenerationSizeIncrement") \ 562 range(1, max_uintx) \ 563 \ 564 product(uintx, MaxGCPauseMillis, max_uintx - 1, \ 565 "Adaptive size policy maximum GC pause time goal in millisecond, "\ 566 "or (G1 Only) the maximum GC time per MMU time slice") \ 567 range(1, max_uintx - 1) \ 568 constraint(MaxGCPauseMillisConstraintFunc,AfterErgo) \ 569 \ 570 product(uintx, GCPauseIntervalMillis, 0, \ 571 "Time slice for MMU specification") \ 572 constraint(GCPauseIntervalMillisConstraintFunc,AfterErgo) \ 573 \ 574 product(uintx, MaxGCMinorPauseMillis, max_uintx, \ 575 "Adaptive size policy maximum GC minor pause time goal " \ 576 "in millisecond") \ 577 range(0, max_uintx) \ 578 \ 579 product(uintx, GCTimeRatio, 99, \ 580 "Adaptive size policy application time to GC time ratio") \ 581 range(0, max_juint) \ 582 \ 583 product(uintx, AdaptiveSizeDecrementScaleFactor, 4, \ 584 "Adaptive size scale down factor for shrinking") \ 585 range(1, max_uintx) \ 586 \ 587 product(bool, UseAdaptiveSizeDecayMajorGCCost, true, \ 588 "Adaptive size decays the major cost for long major intervals") \ 589 \ 590 product(uintx, AdaptiveSizeMajorGCDecayTimeScale, 10, \ 591 "Time scale over which major costs decay") \ 592 range(0, max_uintx) \ 593 \ 594 product(uintx, MinSurvivorRatio, 3, \ 595 "Minimum ratio of young generation/survivor space size") \ 596 range(3, max_uintx) \ 597 \ 598 product(uintx, InitialSurvivorRatio, 8, \ 599 "Initial ratio of young generation/survivor space size") \ 600 range(0, max_uintx) \ 601 \ 602 product(size_t, BaseFootPrintEstimate, 256*M, \ 603 "Estimate of footprint other than Java Heap") \ 604 range(0, max_uintx) \ 605 \ 606 product(bool, UseGCOverheadLimit, true, \ 607 "Use policy to limit of proportion of time spent in GC " \ 608 "before an OutOfMemory error is thrown") \ 609 \ 610 product(uintx, GCTimeLimit, 98, \ 611 "Limit of the proportion of time spent in GC before " \ 612 "an OutOfMemoryError is thrown (used with GCHeapFreeLimit)") \ 613 range(0, 100) \ 614 \ 615 product(uintx, GCHeapFreeLimit, 2, \ 616 "Minimum percentage of free space after a full GC before an " \ 617 "OutOfMemoryError is thrown (used with GCTimeLimit)") \ 618 range(0, 100) \ 619 \ 620 develop(uintx, GCOverheadLimitThreshold, 5, \ 621 "Number of consecutive collections before gc time limit fires") \ 622 range(1, max_uintx) \ 623 \ 624 product(intx, PrefetchCopyIntervalInBytes, -1, \ 625 "How far ahead to prefetch destination area (<= 0 means off)") \ 626 range(-1, max_jint) \ 627 \ 628 product(intx, PrefetchScanIntervalInBytes, -1, \ 629 "How far ahead to prefetch scan area (<= 0 means off)") \ 630 range(-1, max_jint) \ 631 \ 632 product(intx, PrefetchFieldsAhead, -1, \ 633 "How many fields ahead to prefetch in oop scan (<= 0 means off)") \ 634 range(-1, max_jint) \ 635 \ 636 diagnostic(bool, VerifyDuringStartup, false, \ 637 "Verify memory system before executing any Java code " \ 638 "during VM initialization") \ 639 \ 640 diagnostic(bool, VerifyBeforeExit, trueInDebug, \ 641 "Verify system before exiting") \ 642 \ 643 diagnostic(bool, VerifyBeforeGC, false, \ 644 "Verify memory system before GC") \ 645 \ 646 diagnostic(bool, VerifyAfterGC, false, \ 647 "Verify memory system after GC") \ 648 \ 649 diagnostic(bool, VerifyDuringGC, false, \ 650 "Verify memory system during GC (between phases)") \ 651 \ 652 diagnostic(ccstrlist, VerifyGCType, "", \ 653 "GC type(s) to verify when Verify*GC is enabled." \ 654 "Available types are collector specific.") \ 655 \ 656 diagnostic(ccstrlist, VerifySubSet, "", \ 657 "Memory sub-systems to verify when Verify*GC flag(s) " \ 658 "are enabled. One or more sub-systems can be specified " \ 659 "in a comma separated string. Sub-systems are: " \ 660 "threads, heap, symbol_table, string_table, codecache, " \ 661 "dictionary, classloader_data_graph, metaspace, jni_handles, " \ 662 "codecache_oops") \ 663 \ 664 diagnostic(bool, GCParallelVerificationEnabled, true, \ 665 "Enable parallel memory system verification") \ 666 \ 667 diagnostic(bool, DeferInitialCardMark, false, \ 668 "When +ReduceInitialCardMarks, explicitly defer any that " \ 669 "may arise from new_pre_store_barrier") \ 670 \ 671 product(bool, UseCondCardMark, false, \ 672 "Check for already marked card before updating card table") \ 673 \ 674 diagnostic(bool, VerifyRememberedSets, false, \ 675 "Verify GC remembered sets") \ 676 \ 677 diagnostic(bool, VerifyObjectStartArray, true, \ 678 "Verify GC object start array if verify before/after") \ 679 \ 680 product(bool, DisableExplicitGC, false, \ 681 "Ignore calls to System.gc()") \ 682 \ 683 product(bool, BindGCTaskThreadsToCPUs, false, \ 684 "Bind GCTaskThreads to CPUs if possible") \ 685 \ 686 product(bool, UseGCTaskAffinity, false, \ 687 "Use worker affinity when asking for GCTasks") \ 688 \ 689 product(bool, PrintGC, false, \ 690 "Print message at garbage collection. " \ 691 "Deprecated, use -Xlog:gc instead.") \ 692 \ 693 product(bool, PrintGCDetails, false, \ 694 "Print more details at garbage collection. " \ 695 "Deprecated, use -Xlog:gc* instead.") \ 696 \ 697 develop(intx, ConcGCYieldTimeout, 0, \ 698 "If non-zero, assert that GC threads yield within this " \ 699 "number of milliseconds") \ 700 range(0, max_intx) \ 701 \ 702 notproduct(intx, ScavengeALotInterval, 1, \ 703 "Interval between which scavenge will occur with +ScavengeALot") \ 704 \ 705 notproduct(intx, FullGCALotInterval, 1, \ 706 "Interval between which full gc will occur with +FullGCALot") \ 707 \ 708 notproduct(intx, FullGCALotStart, 0, \ 709 "For which invocation to start FullGCAlot") \ 710 \ 711 notproduct(intx, FullGCALotDummies, 32*K, \ 712 "Dummy object allocated with +FullGCALot, forcing all objects " \ 713 "to move") \ 714 \ 715 /* gc parameters */ \ 716 product(size_t, MinHeapSize, 0, \ 717 "Minimum heap size (in bytes); zero means use ergonomics") \ 718 constraint(MinimumHeapSizeConstraintFunc,AfterErgo) \ 719 \ 720 product(size_t, InitialHeapSize, 0, \ 721 "Initial heap size (in bytes); zero means use ergonomics") \ 722 constraint(InitialHeapSizeConstraintFunc,AfterErgo) \ 723 \ 724 product(size_t, MaxHeapSize, ScaleForWordSize(96*M), \ 725 "Maximum heap size (in bytes)") \ 726 constraint(MaxHeapSizeConstraintFunc,AfterErgo) \ 727 \ 728 product(size_t, OldSize, ScaleForWordSize(4*M), \ 729 "Initial tenured generation size (in bytes)") \ 730 range(0, max_uintx) \ 731 \ 732 product(size_t, NewSize, ScaleForWordSize(1*M), \ 733 "Initial new generation size (in bytes)") \ 734 constraint(NewSizeConstraintFunc,AfterErgo) \ 735 \ 736 product(size_t, MaxNewSize, max_uintx, \ 737 "Maximum new generation size (in bytes), max_uintx means set " \ 738 "ergonomically") \ 739 range(0, max_uintx) \ 740 \ 741 product_pd(size_t, HeapBaseMinAddress, \ 742 "OS specific low limit for heap base address") \ 743 constraint(HeapBaseMinAddressConstraintFunc,AfterErgo) \ 744 \ 745 product(size_t, PretenureSizeThreshold, 0, \ 746 "Maximum size in bytes of objects allocated in DefNew " \ 747 "generation; zero means no maximum") \ 748 range(0, max_uintx) \ 749 \ 750 product(size_t, MinTLABSize, 2*K, \ 751 "Minimum allowed TLAB size (in bytes)") \ 752 range(1, max_uintx/2) \ 753 constraint(MinTLABSizeConstraintFunc,AfterMemoryInit) \ 754 \ 755 product(size_t, TLABSize, 0, \ 756 "Starting TLAB size (in bytes); zero means set ergonomically") \ 757 constraint(TLABSizeConstraintFunc,AfterMemoryInit) \ 758 \ 759 product(size_t, YoungPLABSize, 4096, \ 760 "Size of young gen promotion LAB's (in HeapWords)") \ 761 constraint(YoungPLABSizeConstraintFunc,AfterMemoryInit) \ 762 \ 763 product(size_t, OldPLABSize, 1024, \ 764 "Size of old gen promotion LAB's (in HeapWords), or Number " \ 765 "of blocks to attempt to claim when refilling CMS LAB's") \ 766 constraint(OldPLABSizeConstraintFunc,AfterMemoryInit) \ 767 \ 768 product(uintx, TLABAllocationWeight, 35, \ 769 "Allocation averaging weight") \ 770 range(0, 100) \ 771 \ 772 /* Limit the lower bound of this flag to 1 as it is used */ \ 773 /* in a division expression. */ \ 774 product(uintx, TLABWasteTargetPercent, 1, \ 775 "Percentage of Eden that can be wasted") \ 776 range(1, 100) \ 777 \ 778 product(uintx, TLABRefillWasteFraction, 64, \ 779 "Maximum TLAB waste at a refill (internal fragmentation)") \ 780 range(1, max_juint) \ 781 \ 782 product(uintx, TLABWasteIncrement, 4, \ 783 "Increment allowed waste at slow allocation") \ 784 range(0, max_jint) \ 785 constraint(TLABWasteIncrementConstraintFunc,AfterMemoryInit) \ 786 \ 787 product(uintx, SurvivorRatio, 8, \ 788 "Ratio of eden/survivor space size") \ 789 range(1, max_uintx-2) \ 790 constraint(SurvivorRatioConstraintFunc,AfterMemoryInit) \ 791 \ 792 product(uintx, NewRatio, 2, \ 793 "Ratio of old/new generation sizes") \ 794 range(0, max_uintx-1) \ 795 \ 796 product_pd(size_t, NewSizeThreadIncrease, \ 797 "Additional size added to desired new generation size per " \ 798 "non-daemon thread (in bytes)") \ 799 range(0, max_uintx) \ 800 \ 801 product(uintx, QueuedAllocationWarningCount, 0, \ 802 "Number of times an allocation that queues behind a GC " \ 803 "will retry before printing a warning") \ 804 range(0, max_uintx) \ 805 \ 806 diagnostic(uintx, VerifyGCStartAt, 0, \ 807 "GC invoke count where +VerifyBefore/AfterGC kicks in") \ 808 range(0, max_uintx) \ 809 \ 810 diagnostic(intx, VerifyGCLevel, 0, \ 811 "Generation level at which to start +VerifyBefore/AfterGC") \ 812 range(0, 1) \ 813 \ 814 product(uintx, MaxTenuringThreshold, 15, \ 815 "Maximum value for tenuring threshold") \ 816 range(0, markOopDesc::max_age + 1) \ 817 constraint(MaxTenuringThresholdConstraintFunc,AfterErgo) \ 818 \ 819 product(uintx, InitialTenuringThreshold, 7, \ 820 "Initial value for tenuring threshold") \ 821 range(0, markOopDesc::max_age + 1) \ 822 constraint(InitialTenuringThresholdConstraintFunc,AfterErgo) \ 823 \ 824 product(uintx, TargetSurvivorRatio, 50, \ 825 "Desired percentage of survivor space used after scavenge") \ 826 range(0, 100) \ 827 \ 828 product(uintx, MarkSweepDeadRatio, 5, \ 829 "Percentage (0-100) of the old gen allowed as dead wood. " \ 830 "Serial mark sweep treats this as both the minimum and maximum " \ 831 "value. " \ 832 "CMS uses this value only if it falls back to mark sweep. " \ 833 "Par compact uses a variable scale based on the density of the " \ 834 "generation and treats this as the maximum value when the heap " \ 835 "is either completely full or completely empty. Par compact " \ 836 "also has a smaller default value; see arguments.cpp.") \ 837 range(0, 100) \ 838 \ 839 product(uint, MarkSweepAlwaysCompactCount, 4, \ 840 "How often should we fully compact the heap (ignoring the dead " \ 841 "space parameters)") \ 842 range(1, max_juint) \ 843 \ 844 develop(uintx, GCExpandToAllocateDelayMillis, 0, \ 845 "Delay between expansion and allocation (in milliseconds)") \ 846 \ 847 product(uintx, GCDrainStackTargetSize, 64, \ 848 "Number of entries we will try to leave on the stack " \ 849 "during parallel gc") \ 850 range(0, max_juint) 851 852 #endif // SHARE_GC_SHARED_GC_GLOBALS_HPP