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