1 /* 2 * Copyright (c) 1997, 2020, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #ifndef SHARE_GC_SHARED_GC_GLOBALS_HPP 26 #define SHARE_GC_SHARED_GC_GLOBALS_HPP 27 28 #include "runtime/globals_shared.hpp" 29 #include "utilities/macros.hpp" 30 #if INCLUDE_EPSILONGC 31 #include "gc/epsilon/epsilon_globals.hpp" 32 #endif 33 #if INCLUDE_G1GC 34 #include "gc/g1/g1_globals.hpp" 35 #endif 36 #if INCLUDE_PARALLELGC 37 #include "gc/parallel/parallel_globals.hpp" 38 #endif 39 #if INCLUDE_SERIALGC 40 #include "gc/serial/serial_globals.hpp" 41 #endif 42 #if INCLUDE_SHENANDOAHGC 43 #include "gc/shenandoah/shenandoah_globals.hpp" 44 #endif 45 #if INCLUDE_ZGC 46 #include "gc/z/z_globals.hpp" 47 #endif 48 49 #define GC_FLAGS(develop, \ 50 develop_pd, \ 51 product, \ 52 product_pd, \ 53 diagnostic, \ 54 diagnostic_pd, \ 55 experimental, \ 56 notproduct, \ 57 manageable, \ 58 product_rw, \ 59 lp64_product, \ 60 range, \ 61 constraint) \ 62 \ 63 EPSILONGC_ONLY(GC_EPSILON_FLAGS( \ 64 develop, \ 65 develop_pd, \ 66 product, \ 67 product_pd, \ 68 diagnostic, \ 69 diagnostic_pd, \ 70 experimental, \ 71 notproduct, \ 72 manageable, \ 73 product_rw, \ 74 lp64_product, \ 75 range, \ 76 constraint)) \ 77 \ 78 G1GC_ONLY(GC_G1_FLAGS( \ 79 develop, \ 80 develop_pd, \ 81 product, \ 82 product_pd, \ 83 diagnostic, \ 84 diagnostic_pd, \ 85 experimental, \ 86 notproduct, \ 87 manageable, \ 88 product_rw, \ 89 lp64_product, \ 90 range, \ 91 constraint)) \ 92 \ 93 PARALLELGC_ONLY(GC_PARALLEL_FLAGS( \ 94 develop, \ 95 develop_pd, \ 96 product, \ 97 product_pd, \ 98 diagnostic, \ 99 diagnostic_pd, \ 100 experimental, \ 101 notproduct, \ 102 manageable, \ 103 product_rw, \ 104 lp64_product, \ 105 range, \ 106 constraint)) \ 107 \ 108 SERIALGC_ONLY(GC_SERIAL_FLAGS( \ 109 develop, \ 110 develop_pd, \ 111 product, \ 112 product_pd, \ 113 diagnostic, \ 114 diagnostic_pd, \ 115 experimental, \ 116 notproduct, \ 117 manageable, \ 118 product_rw, \ 119 lp64_product, \ 120 range, \ 121 constraint)) \ 122 \ 123 SHENANDOAHGC_ONLY(GC_SHENANDOAH_FLAGS( \ 124 develop, \ 125 develop_pd, \ 126 product, \ 127 product_pd, \ 128 diagnostic, \ 129 diagnostic_pd, \ 130 experimental, \ 131 notproduct, \ 132 manageable, \ 133 product_rw, \ 134 lp64_product, \ 135 range, \ 136 constraint)) \ 137 \ 138 ZGC_ONLY(GC_Z_FLAGS( \ 139 develop, \ 140 develop_pd, \ 141 product, \ 142 product_pd, \ 143 diagnostic, \ 144 diagnostic_pd, \ 145 experimental, \ 146 notproduct, \ 147 manageable, \ 148 product_rw, \ 149 lp64_product, \ 150 range, \ 151 constraint)) \ 152 \ 153 /* gc */ \ 154 \ 155 product(bool, UseSerialGC, false, \ 156 "Use the Serial garbage collector") \ 157 \ 158 product(bool, UseG1GC, false, \ 159 "Use the Garbage-First garbage collector") \ 160 \ 161 product(bool, UseParallelGC, false, \ 162 "Use the Parallel garbage collector.") \ 163 \ 164 experimental(bool, UseEpsilonGC, false, \ 165 "Use the Epsilon (no-op) garbage collector") \ 166 \ 167 product(bool, UseZGC, false, \ 168 "Use the Z garbage collector") \ 169 \ 170 product(bool, UseShenandoahGC, false, \ 171 "Use the Shenandoah garbage collector") \ 172 \ 173 product(uint, ParallelGCThreads, 0, \ 174 "Number of parallel threads parallel gc will use") \ 175 constraint(ParallelGCThreadsConstraintFunc,AfterErgo) \ 176 \ 177 diagnostic(bool, UseSemaphoreGCThreadsSynchronization, true, \ 178 "Use semaphore synchronization for the GC Threads, " \ 179 "instead of synchronization based on mutexes") \ 180 \ 181 product(bool, UseDynamicNumberOfGCThreads, true, \ 182 "Dynamically choose the number of threads up to a maximum of " \ 183 "ParallelGCThreads parallel collectors will use for garbage " \ 184 "collection work") \ 185 \ 186 diagnostic(bool, InjectGCWorkerCreationFailure, false, \ 187 "Inject thread creation failures for " \ 188 "UseDynamicNumberOfGCThreads") \ 189 \ 190 product(size_t, HeapSizePerGCThread, ScaleForWordSize(32*M), \ 191 "Size of heap (bytes) per GC thread used in calculating the " \ 192 "number of GC threads") \ 193 range((size_t)os::vm_page_size(), (size_t)max_uintx) \ 194 \ 195 product(uint, ConcGCThreads, 0, \ 196 "Number of threads concurrent gc will use") \ 197 constraint(ConcGCThreadsConstraintFunc,AfterErgo) \ 198 \ 199 product(bool, AlwaysTenure, false, \ 200 "Always tenure objects in eden (ParallelGC only)") \ 201 \ 202 product(bool, NeverTenure, false, \ 203 "Never tenure objects in eden, may tenure on overflow " \ 204 "(ParallelGC only)") \ 205 \ 206 product(bool, ScavengeBeforeFullGC, true, \ 207 "Scavenge youngest generation before each full GC.") \ 208 \ 209 product(bool, ExplicitGCInvokesConcurrent, false, \ 210 "A System.gc() request invokes a concurrent collection; " \ 211 "(effective only when using concurrent collectors)") \ 212 \ 213 product(uintx, GCLockerEdenExpansionPercent, 5, \ 214 "How much the GC can expand the eden by while the GC locker " \ 215 "is active (as a percentage)") \ 216 range(0, 100) \ 217 \ 218 diagnostic(uintx, GCLockerRetryAllocationCount, 2, \ 219 "Number of times to retry allocations when " \ 220 "blocked by the GC locker") \ 221 range(0, max_uintx) \ 222 \ 223 product(uintx, ParallelGCBufferWastePct, 10, \ 224 "Wasted fraction of parallel allocation buffer") \ 225 range(0, 100) \ 226 \ 227 product(uintx, TargetPLABWastePct, 10, \ 228 "Target wasted space in last buffer as percent of overall " \ 229 "allocation") \ 230 range(1, 100) \ 231 \ 232 product(uintx, PLABWeight, 75, \ 233 "Percentage (0-100) used to weight the current sample when " \ 234 "computing exponentially decaying average for ResizePLAB") \ 235 range(0, 100) \ 236 \ 237 product(bool, ResizePLAB, true, \ 238 "Dynamically resize (survivor space) promotion LAB's") \ 239 \ 240 product(int, ParGCArrayScanChunk, 50, \ 241 "Scan a subset of object array and push remainder, if array is " \ 242 "bigger than this") \ 243 range(1, max_jint/3) \ 244 \ 245 \ 246 product(bool, AlwaysPreTouch, false, \ 247 "Force all freshly committed pages to be pre-touched") \ 248 \ 249 product(size_t, PreTouchParallelChunkSize, 1 * G, \ 250 "Per-thread chunk size for parallel memory pre-touch.") \ 251 range(1, SIZE_MAX / 2) \ 252 \ 253 /* where does the range max value of (max_jint - 1) come from? */ \ 254 product(size_t, MarkStackSizeMax, NOT_LP64(4*M) LP64_ONLY(512*M), \ 255 "Maximum size of marking stack") \ 256 range(1, (max_jint - 1)) \ 257 \ 258 product(size_t, MarkStackSize, NOT_LP64(32*K) LP64_ONLY(4*M), \ 259 "Size of marking stack") \ 260 constraint(MarkStackSizeConstraintFunc,AfterErgo) \ 261 range(1, (max_jint - 1)) \ 262 \ 263 product(intx, RefDiscoveryPolicy, 0, \ 264 "Select type of reference discovery policy: " \ 265 "reference-based(0) or referent-based(1)") \ 266 range(ReferenceProcessor::DiscoveryPolicyMin, \ 267 ReferenceProcessor::DiscoveryPolicyMax) \ 268 \ 269 product(bool, ParallelRefProcEnabled, false, \ 270 "Enable parallel reference processing whenever possible") \ 271 \ 272 product(bool, ParallelRefProcBalancingEnabled, true, \ 273 "Enable balancing of reference processing queues") \ 274 \ 275 experimental(size_t, ReferencesPerThread, 1000, \ 276 "Ergonomically start one thread for this amount of " \ 277 "references for reference processing if " \ 278 "ParallelRefProcEnabled is true. Specify 0 to disable and " \ 279 "use all threads.") \ 280 \ 281 product(uintx, InitiatingHeapOccupancyPercent, 45, \ 282 "The percent occupancy (IHOP) of the current old generation " \ 283 "capacity above which a concurrent mark cycle will be initiated " \ 284 "Its value may change over time if adaptive IHOP is enabled, " \ 285 "otherwise the value remains constant. " \ 286 "In the latter case a value of 0 will result as frequent as " \ 287 "possible concurrent marking cycles. A value of 100 disables " \ 288 "concurrent marking. " \ 289 "Fragmentation waste in the old generation is not considered " \ 290 "free space in this calculation. (G1 collector only)") \ 291 range(0, 100) \ 292 \ 293 notproduct(bool, ScavengeALot, false, \ 294 "Force scavenge at every Nth exit from the runtime system " \ 295 "(N=ScavengeALotInterval)") \ 296 \ 297 develop(bool, FullGCALot, false, \ 298 "Force full gc at every Nth exit from the runtime system " \ 299 "(N=FullGCALotInterval)") \ 300 \ 301 notproduct(bool, GCALotAtAllSafepoints, false, \ 302 "Enforce ScavengeALot/GCALot at all potential safepoints") \ 303 \ 304 notproduct(bool, PromotionFailureALot, false, \ 305 "Use promotion failure handling on every youngest generation " \ 306 "collection") \ 307 \ 308 develop(uintx, PromotionFailureALotCount, 1000, \ 309 "Number of promotion failures occurring at PLAB promotion " \ 310 "attempts at young collectors") \ 311 \ 312 develop(uintx, PromotionFailureALotInterval, 5, \ 313 "Total collections between promotion failures a lot") \ 314 \ 315 experimental(uintx, WorkStealingSleepMillis, 1, \ 316 "Sleep time when sleep is used for yields") \ 317 \ 318 experimental(uintx, WorkStealingYieldsBeforeSleep, 5000, \ 319 "Number of yields before a sleep is done during work stealing") \ 320 \ 321 experimental(uintx, WorkStealingHardSpins, 4096, \ 322 "Number of iterations in a spin loop between checks on " \ 323 "time out of hard spin") \ 324 \ 325 experimental(uintx, WorkStealingSpinToYieldRatio, 10, \ 326 "Ratio of hard spins to calls to yield") \ 327 \ 328 develop(uintx, ObjArrayMarkingStride, 2048, \ 329 "Number of object array elements to push onto the marking stack " \ 330 "before pushing a continuation entry") \ 331 \ 332 develop(bool, MetadataAllocationFailALot, false, \ 333 "Fail metadata allocations at intervals controlled by " \ 334 "MetadataAllocationFailALotInterval") \ 335 \ 336 develop(uintx, MetadataAllocationFailALotInterval, 1000, \ 337 "Metadata allocation failure a lot interval") \ 338 \ 339 product(bool, ExecutingUnitTests, false, \ 340 "Whether the JVM is running unit tests or not") \ 341 \ 342 product_pd(bool, UseTLAB, "Use thread-local object allocation") \ 343 \ 344 product_pd(bool, ResizeTLAB, \ 345 "Dynamically resize TLAB size for threads") \ 346 \ 347 product(bool, ZeroTLAB, false, \ 348 "Zero out the newly created TLAB") \ 349 \ 350 product(bool, TLABStats, true, \ 351 "Provide more detailed and expensive TLAB statistics.") \ 352 \ 353 product_pd(bool, NeverActAsServerClassMachine, \ 354 "Never act like a server-class machine") \ 355 \ 356 product(bool, AlwaysActAsServerClassMachine, false, \ 357 "Always act like a server-class machine") \ 358 \ 359 product_pd(uint64_t, MaxRAM, \ 360 "Real memory size (in bytes) used to set maximum heap size") \ 361 range(0, 0XFFFFFFFFFFFFFFFF) \ 362 \ 363 product(bool, AggressiveHeap, false, \ 364 "Optimize heap options for long-running memory intensive apps") \ 365 \ 366 product(size_t, ErgoHeapSizeLimit, 0, \ 367 "Maximum ergonomically set heap size (in bytes); zero means use " \ 368 "MaxRAM * MaxRAMPercentage / 100") \ 369 range(0, max_uintx) \ 370 \ 371 product(uintx, MaxRAMFraction, 4, \ 372 "Maximum fraction (1/n) of real memory used for maximum heap " \ 373 "size. " \ 374 "Deprecated, use MaxRAMPercentage instead") \ 375 range(1, max_uintx) \ 376 \ 377 product(uintx, MinRAMFraction, 2, \ 378 "Minimum fraction (1/n) of real memory used for maximum heap " \ 379 "size on systems with small physical memory size. " \ 380 "Deprecated, use MinRAMPercentage instead") \ 381 range(1, max_uintx) \ 382 \ 383 product(uintx, InitialRAMFraction, 64, \ 384 "Fraction (1/n) of real memory used for initial heap size. " \ 385 "Deprecated, use InitialRAMPercentage instead") \ 386 range(1, max_uintx) \ 387 \ 388 product(double, MaxRAMPercentage, 25.0, \ 389 "Maximum percentage of real memory used for maximum heap size") \ 390 range(0.0, 100.0) \ 391 \ 392 product(double, MinRAMPercentage, 50.0, \ 393 "Minimum percentage of real memory used for maximum heap" \ 394 "size on systems with small physical memory size") \ 395 range(0.0, 100.0) \ 396 \ 397 product(double, InitialRAMPercentage, 1.5625, \ 398 "Percentage of real memory used for initial heap size") \ 399 range(0.0, 100.0) \ 400 \ 401 product(int, ActiveProcessorCount, -1, \ 402 "Specify the CPU count the VM should use and report as active") \ 403 \ 404 develop(uintx, MaxVirtMemFraction, 2, \ 405 "Maximum fraction (1/n) of virtual memory used for ergonomically "\ 406 "determining maximum heap size") \ 407 \ 408 product(bool, UseAdaptiveSizePolicy, true, \ 409 "Use adaptive generation sizing policies") \ 410 \ 411 product(bool, UsePSAdaptiveSurvivorSizePolicy, true, \ 412 "Use adaptive survivor sizing policies") \ 413 \ 414 product(bool, UseAdaptiveGenerationSizePolicyAtMinorCollection, true, \ 415 "Use adaptive young-old sizing policies at minor collections") \ 416 \ 417 product(bool, UseAdaptiveGenerationSizePolicyAtMajorCollection, true, \ 418 "Use adaptive young-old sizing policies at major collections") \ 419 \ 420 product(bool, UseAdaptiveSizePolicyWithSystemGC, false, \ 421 "Include statistics from System.gc() for adaptive size policy") \ 422 \ 423 develop(intx, PSAdaptiveSizePolicyResizeVirtualSpaceAlot, -1, \ 424 "Resize the virtual spaces of the young or old generations") \ 425 range(-1, 1) \ 426 \ 427 product(uintx, AdaptiveSizeThroughPutPolicy, 0, \ 428 "Policy for changing generation size for throughput goals") \ 429 range(0, 1) \ 430 \ 431 product(uintx, AdaptiveSizePolicyInitializingSteps, 20, \ 432 "Number of steps where heuristics is used before data is used") \ 433 range(0, max_uintx) \ 434 \ 435 develop(uintx, AdaptiveSizePolicyReadyThreshold, 5, \ 436 "Number of collections before the adaptive sizing is started") \ 437 \ 438 product(uintx, AdaptiveSizePolicyOutputInterval, 0, \ 439 "Collection interval for printing information; zero means never") \ 440 range(0, max_uintx) \ 441 \ 442 product(bool, UseAdaptiveSizePolicyFootprintGoal, true, \ 443 "Use adaptive minimum footprint as a goal") \ 444 \ 445 product(uintx, AdaptiveSizePolicyWeight, 10, \ 446 "Weight given to exponential resizing, between 0 and 100") \ 447 range(0, 100) \ 448 \ 449 product(uintx, AdaptiveTimeWeight, 25, \ 450 "Weight given to time in adaptive policy, between 0 and 100") \ 451 range(0, 100) \ 452 \ 453 product(uintx, PausePadding, 1, \ 454 "How much buffer to keep for pause time") \ 455 range(0, max_juint) \ 456 \ 457 product(uintx, PromotedPadding, 3, \ 458 "How much buffer to keep for promotion failure") \ 459 range(0, max_juint) \ 460 \ 461 product(uintx, SurvivorPadding, 3, \ 462 "How much buffer to keep for survivor overflow") \ 463 range(0, max_juint) \ 464 \ 465 product(uintx, ThresholdTolerance, 10, \ 466 "Allowed collection cost difference between generations") \ 467 range(0, 100) \ 468 \ 469 product(uintx, AdaptiveSizePolicyCollectionCostMargin, 50, \ 470 "If collection costs are within margin, reduce both by full " \ 471 "delta") \ 472 range(0, 100) \ 473 \ 474 product(uintx, YoungGenerationSizeIncrement, 20, \ 475 "Adaptive size percentage change in young generation") \ 476 range(0, 100) \ 477 \ 478 product(uintx, YoungGenerationSizeSupplement, 80, \ 479 "Supplement to YoungedGenerationSizeIncrement used at startup") \ 480 range(0, 100) \ 481 \ 482 product(uintx, YoungGenerationSizeSupplementDecay, 8, \ 483 "Decay factor to YoungedGenerationSizeSupplement") \ 484 range(1, max_uintx) \ 485 \ 486 product(uintx, TenuredGenerationSizeIncrement, 20, \ 487 "Adaptive size percentage change in tenured generation") \ 488 range(0, 100) \ 489 \ 490 product(uintx, TenuredGenerationSizeSupplement, 80, \ 491 "Supplement to TenuredGenerationSizeIncrement used at startup") \ 492 range(0, 100) \ 493 \ 494 product(uintx, TenuredGenerationSizeSupplementDecay, 2, \ 495 "Decay factor to TenuredGenerationSizeIncrement") \ 496 range(1, max_uintx) \ 497 \ 498 product(uintx, MaxGCPauseMillis, max_uintx - 1, \ 499 "Adaptive size policy maximum GC pause time goal in millisecond, "\ 500 "or (G1 Only) the maximum GC time per MMU time slice") \ 501 range(1, max_uintx - 1) \ 502 constraint(MaxGCPauseMillisConstraintFunc,AfterErgo) \ 503 \ 504 product(uintx, GCPauseIntervalMillis, 0, \ 505 "Time slice for MMU specification") \ 506 constraint(GCPauseIntervalMillisConstraintFunc,AfterErgo) \ 507 \ 508 product(uintx, MaxGCMinorPauseMillis, max_uintx, \ 509 "Adaptive size policy maximum GC minor pause time goal " \ 510 "in millisecond") \ 511 range(0, max_uintx) \ 512 \ 513 product(uintx, GCTimeRatio, 99, \ 514 "Adaptive size policy application time to GC time ratio") \ 515 range(0, max_juint) \ 516 \ 517 product(uintx, AdaptiveSizeDecrementScaleFactor, 4, \ 518 "Adaptive size scale down factor for shrinking") \ 519 range(1, max_uintx) \ 520 \ 521 product(bool, UseAdaptiveSizeDecayMajorGCCost, true, \ 522 "Adaptive size decays the major cost for long major intervals") \ 523 \ 524 product(uintx, AdaptiveSizeMajorGCDecayTimeScale, 10, \ 525 "Time scale over which major costs decay") \ 526 range(0, max_uintx) \ 527 \ 528 product(uintx, MinSurvivorRatio, 3, \ 529 "Minimum ratio of young generation/survivor space size") \ 530 range(3, max_uintx) \ 531 \ 532 product(uintx, InitialSurvivorRatio, 8, \ 533 "Initial ratio of young generation/survivor space size") \ 534 range(0, max_uintx) \ 535 \ 536 product(size_t, BaseFootPrintEstimate, 256*M, \ 537 "Estimate of footprint other than Java Heap") \ 538 range(0, max_uintx) \ 539 \ 540 product(bool, UseGCOverheadLimit, true, \ 541 "Use policy to limit of proportion of time spent in GC " \ 542 "before an OutOfMemory error is thrown") \ 543 \ 544 product(uintx, GCTimeLimit, 98, \ 545 "Limit of the proportion of time spent in GC before " \ 546 "an OutOfMemoryError is thrown (used with GCHeapFreeLimit)") \ 547 range(0, 100) \ 548 \ 549 product(uintx, GCHeapFreeLimit, 2, \ 550 "Minimum percentage of free space after a full GC before an " \ 551 "OutOfMemoryError is thrown (used with GCTimeLimit)") \ 552 range(0, 100) \ 553 \ 554 develop(uintx, GCOverheadLimitThreshold, 5, \ 555 "Number of consecutive collections before gc time limit fires") \ 556 range(1, max_uintx) \ 557 \ 558 product(intx, PrefetchCopyIntervalInBytes, -1, \ 559 "How far ahead to prefetch destination area (<= 0 means off)") \ 560 range(-1, max_jint) \ 561 \ 562 product(intx, PrefetchScanIntervalInBytes, -1, \ 563 "How far ahead to prefetch scan area (<= 0 means off)") \ 564 range(-1, max_jint) \ 565 \ 566 product(intx, PrefetchFieldsAhead, -1, \ 567 "How many fields ahead to prefetch in oop scan (<= 0 means off)") \ 568 range(-1, max_jint) \ 569 \ 570 diagnostic(bool, VerifyDuringStartup, false, \ 571 "Verify memory system before executing any Java code " \ 572 "during VM initialization") \ 573 \ 574 diagnostic(bool, VerifyBeforeExit, trueInDebug, \ 575 "Verify system before exiting") \ 576 \ 577 diagnostic(bool, VerifyBeforeGC, false, \ 578 "Verify memory system before GC") \ 579 \ 580 diagnostic(bool, VerifyAfterGC, false, \ 581 "Verify memory system after GC") \ 582 \ 583 diagnostic(bool, VerifyDuringGC, false, \ 584 "Verify memory system during GC (between phases)") \ 585 \ 586 diagnostic(ccstrlist, VerifyGCType, "", \ 587 "GC type(s) to verify when Verify*GC is enabled." \ 588 "Available types are collector specific.") \ 589 \ 590 diagnostic(ccstrlist, VerifySubSet, "", \ 591 "Memory sub-systems to verify when Verify*GC flag(s) " \ 592 "are enabled. One or more sub-systems can be specified " \ 593 "in a comma separated string. Sub-systems are: " \ 594 "threads, heap, symbol_table, string_table, codecache, " \ 595 "dictionary, classloader_data_graph, metaspace, jni_handles, " \ 596 "codecache_oops") \ 597 \ 598 diagnostic(bool, GCParallelVerificationEnabled, true, \ 599 "Enable parallel memory system verification") \ 600 \ 601 diagnostic(bool, DeferInitialCardMark, false, \ 602 "When +ReduceInitialCardMarks, explicitly defer any that " \ 603 "may arise from new_pre_store_barrier") \ 604 \ 605 product(bool, UseCondCardMark, false, \ 606 "Check for already marked card before updating card table") \ 607 \ 608 diagnostic(bool, VerifyRememberedSets, false, \ 609 "Verify GC remembered sets") \ 610 \ 611 diagnostic(bool, VerifyObjectStartArray, true, \ 612 "Verify GC object start array if verify before/after") \ 613 \ 614 product(bool, DisableExplicitGC, false, \ 615 "Ignore calls to System.gc()") \ 616 \ 617 product(bool, PrintGC, false, \ 618 "Print message at garbage collection. " \ 619 "Deprecated, use -Xlog:gc instead.") \ 620 \ 621 product(bool, PrintGCDetails, false, \ 622 "Print more details at garbage collection. " \ 623 "Deprecated, use -Xlog:gc* instead.") \ 624 \ 625 develop(intx, ConcGCYieldTimeout, 0, \ 626 "If non-zero, assert that GC threads yield within this " \ 627 "number of milliseconds") \ 628 range(0, max_intx) \ 629 \ 630 notproduct(intx, ScavengeALotInterval, 1, \ 631 "Interval between which scavenge will occur with +ScavengeALot") \ 632 \ 633 notproduct(intx, FullGCALotInterval, 1, \ 634 "Interval between which full gc will occur with +FullGCALot") \ 635 \ 636 notproduct(intx, FullGCALotStart, 0, \ 637 "For which invocation to start FullGCAlot") \ 638 \ 639 notproduct(intx, FullGCALotDummies, 32*K, \ 640 "Dummy object allocated with +FullGCALot, forcing all objects " \ 641 "to move") \ 642 \ 643 /* gc parameters */ \ 644 product(size_t, MinHeapSize, 0, \ 645 "Minimum heap size (in bytes); zero means use ergonomics") \ 646 constraint(MinHeapSizeConstraintFunc,AfterErgo) \ 647 \ 648 product(size_t, InitialHeapSize, 0, \ 649 "Initial heap size (in bytes); zero means use ergonomics") \ 650 constraint(InitialHeapSizeConstraintFunc,AfterErgo) \ 651 \ 652 product(size_t, MaxHeapSize, ScaleForWordSize(96*M), \ 653 "Maximum heap size (in bytes)") \ 654 constraint(MaxHeapSizeConstraintFunc,AfterErgo) \ 655 \ 656 manageable(size_t, SoftMaxHeapSize, 0, \ 657 "Soft limit for maximum heap size (in bytes)") \ 658 constraint(SoftMaxHeapSizeConstraintFunc,AfterMemoryInit) \ 659 \ 660 product(size_t, OldSize, ScaleForWordSize(4*M), \ 661 "Initial tenured generation size (in bytes)") \ 662 range(0, max_uintx) \ 663 \ 664 product(size_t, NewSize, ScaleForWordSize(1*M), \ 665 "Initial new generation size (in bytes)") \ 666 constraint(NewSizeConstraintFunc,AfterErgo) \ 667 \ 668 product(size_t, MaxNewSize, max_uintx, \ 669 "Maximum new generation size (in bytes), max_uintx means set " \ 670 "ergonomically") \ 671 range(0, max_uintx) \ 672 \ 673 product_pd(size_t, HeapBaseMinAddress, \ 674 "OS specific low limit for heap base address") \ 675 constraint(HeapBaseMinAddressConstraintFunc,AfterErgo) \ 676 \ 677 product(size_t, PretenureSizeThreshold, 0, \ 678 "Maximum size in bytes of objects allocated in DefNew " \ 679 "generation; zero means no maximum") \ 680 range(0, max_uintx) \ 681 \ 682 product(size_t, MinTLABSize, 2*K, \ 683 "Minimum allowed TLAB size (in bytes)") \ 684 range(1, max_uintx/2) \ 685 constraint(MinTLABSizeConstraintFunc,AfterMemoryInit) \ 686 \ 687 product(size_t, TLABSize, 0, \ 688 "Starting TLAB size (in bytes); zero means set ergonomically") \ 689 constraint(TLABSizeConstraintFunc,AfterMemoryInit) \ 690 \ 691 product(size_t, YoungPLABSize, 4096, \ 692 "Size of young gen promotion LAB's (in HeapWords)") \ 693 constraint(YoungPLABSizeConstraintFunc,AfterMemoryInit) \ 694 \ 695 product(size_t, OldPLABSize, 1024, \ 696 "Size of old gen promotion LAB's (in HeapWords)") \ 697 constraint(OldPLABSizeConstraintFunc,AfterMemoryInit) \ 698 \ 699 product(uintx, TLABAllocationWeight, 35, \ 700 "Allocation averaging weight") \ 701 range(0, 100) \ 702 \ 703 /* Limit the lower bound of this flag to 1 as it is used */ \ 704 /* in a division expression. */ \ 705 product(uintx, TLABWasteTargetPercent, 1, \ 706 "Percentage of Eden that can be wasted") \ 707 range(1, 100) \ 708 \ 709 product(uintx, TLABRefillWasteFraction, 64, \ 710 "Maximum TLAB waste at a refill (internal fragmentation)") \ 711 range(1, max_juint) \ 712 \ 713 product(uintx, TLABWasteIncrement, 4, \ 714 "Increment allowed waste at slow allocation") \ 715 range(0, max_jint) \ 716 constraint(TLABWasteIncrementConstraintFunc,AfterMemoryInit) \ 717 \ 718 product(uintx, SurvivorRatio, 8, \ 719 "Ratio of eden/survivor space size") \ 720 range(1, max_uintx-2) \ 721 constraint(SurvivorRatioConstraintFunc,AfterMemoryInit) \ 722 \ 723 product(uintx, NewRatio, 2, \ 724 "Ratio of old/new generation sizes") \ 725 range(0, max_uintx-1) \ 726 \ 727 product_pd(size_t, NewSizeThreadIncrease, \ 728 "Additional size added to desired new generation size per " \ 729 "non-daemon thread (in bytes)") \ 730 range(0, max_uintx) \ 731 \ 732 product(uintx, QueuedAllocationWarningCount, 0, \ 733 "Number of times an allocation that queues behind a GC " \ 734 "will retry before printing a warning") \ 735 range(0, max_uintx) \ 736 \ 737 diagnostic(uintx, VerifyGCStartAt, 0, \ 738 "GC invoke count where +VerifyBefore/AfterGC kicks in") \ 739 range(0, max_uintx) \ 740 \ 741 diagnostic(intx, VerifyGCLevel, 0, \ 742 "Generation level at which to start +VerifyBefore/AfterGC") \ 743 range(0, 1) \ 744 \ 745 product(uintx, MaxTenuringThreshold, 15, \ 746 "Maximum value for tenuring threshold") \ 747 range(0, markWord::max_age + 1) \ 748 constraint(MaxTenuringThresholdConstraintFunc,AfterErgo) \ 749 \ 750 product(uintx, InitialTenuringThreshold, 7, \ 751 "Initial value for tenuring threshold") \ 752 range(0, markWord::max_age + 1) \ 753 constraint(InitialTenuringThresholdConstraintFunc,AfterErgo) \ 754 \ 755 product(uintx, TargetSurvivorRatio, 50, \ 756 "Desired percentage of survivor space used after scavenge") \ 757 range(0, 100) \ 758 \ 759 product(uintx, MarkSweepDeadRatio, 5, \ 760 "Percentage (0-100) of the old gen allowed as dead wood. " \ 761 "Serial mark sweep treats this as both the minimum and maximum " \ 762 "value. " \ 763 "Par compact uses a variable scale based on the density of the " \ 764 "generation and treats this as the maximum value when the heap " \ 765 "is either completely full or completely empty. Par compact " \ 766 "also has a smaller default value; see arguments.cpp.") \ 767 range(0, 100) \ 768 \ 769 product(uint, MarkSweepAlwaysCompactCount, 4, \ 770 "How often should we fully compact the heap (ignoring the dead " \ 771 "space parameters)") \ 772 range(1, max_juint) \ 773 \ 774 develop(uintx, GCExpandToAllocateDelayMillis, 0, \ 775 "Delay between expansion and allocation (in milliseconds)") \ 776 \ 777 product(uintx, GCDrainStackTargetSize, 64, \ 778 "Number of entries we will try to leave on the stack " \ 779 "during parallel gc") \ 780 range(0, max_juint) 781 782 #endif // SHARE_GC_SHARED_GC_GLOBALS_HPP