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 experimental(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 product(bool, UseAdaptiveGCBoundary, false, \ 424 "Allow young-old boundary to move") \ 425 \ 426 develop(intx, PSAdaptiveSizePolicyResizeVirtualSpaceAlot, -1, \ 427 "Resize the virtual spaces of the young or old generations") \ 428 range(-1, 1) \ 429 \ 430 product(uintx, AdaptiveSizeThroughPutPolicy, 0, \ 431 "Policy for changing generation size for throughput goals") \ 432 range(0, 1) \ 433 \ 434 product(uintx, AdaptiveSizePolicyInitializingSteps, 20, \ 435 "Number of steps where heuristics is used before data is used") \ 436 range(0, max_uintx) \ 437 \ 438 develop(uintx, AdaptiveSizePolicyReadyThreshold, 5, \ 439 "Number of collections before the adaptive sizing is started") \ 440 \ 441 product(uintx, AdaptiveSizePolicyOutputInterval, 0, \ 442 "Collection interval for printing information; zero means never") \ 443 range(0, max_uintx) \ 444 \ 445 product(bool, UseAdaptiveSizePolicyFootprintGoal, true, \ 446 "Use adaptive minimum footprint as a goal") \ 447 \ 448 product(uintx, AdaptiveSizePolicyWeight, 10, \ 449 "Weight given to exponential resizing, between 0 and 100") \ 450 range(0, 100) \ 451 \ 452 product(uintx, AdaptiveTimeWeight, 25, \ 453 "Weight given to time in adaptive policy, between 0 and 100") \ 454 range(0, 100) \ 455 \ 456 product(uintx, PausePadding, 1, \ 457 "How much buffer to keep for pause time") \ 458 range(0, max_juint) \ 459 \ 460 product(uintx, PromotedPadding, 3, \ 461 "How much buffer to keep for promotion failure") \ 462 range(0, max_juint) \ 463 \ 464 product(uintx, SurvivorPadding, 3, \ 465 "How much buffer to keep for survivor overflow") \ 466 range(0, max_juint) \ 467 \ 468 product(uintx, ThresholdTolerance, 10, \ 469 "Allowed collection cost difference between generations") \ 470 range(0, 100) \ 471 \ 472 product(uintx, AdaptiveSizePolicyCollectionCostMargin, 50, \ 473 "If collection costs are within margin, reduce both by full " \ 474 "delta") \ 475 range(0, 100) \ 476 \ 477 product(uintx, YoungGenerationSizeIncrement, 20, \ 478 "Adaptive size percentage change in young generation") \ 479 range(0, 100) \ 480 \ 481 product(uintx, YoungGenerationSizeSupplement, 80, \ 482 "Supplement to YoungedGenerationSizeIncrement used at startup") \ 483 range(0, 100) \ 484 \ 485 product(uintx, YoungGenerationSizeSupplementDecay, 8, \ 486 "Decay factor to YoungedGenerationSizeSupplement") \ 487 range(1, max_uintx) \ 488 \ 489 product(uintx, TenuredGenerationSizeIncrement, 20, \ 490 "Adaptive size percentage change in tenured generation") \ 491 range(0, 100) \ 492 \ 493 product(uintx, TenuredGenerationSizeSupplement, 80, \ 494 "Supplement to TenuredGenerationSizeIncrement used at startup") \ 495 range(0, 100) \ 496 \ 497 product(uintx, TenuredGenerationSizeSupplementDecay, 2, \ 498 "Decay factor to TenuredGenerationSizeIncrement") \ 499 range(1, max_uintx) \ 500 \ 501 product(uintx, MaxGCPauseMillis, max_uintx - 1, \ 502 "Adaptive size policy maximum GC pause time goal in millisecond, "\ 503 "or (G1 Only) the maximum GC time per MMU time slice") \ 504 range(1, max_uintx - 1) \ 505 constraint(MaxGCPauseMillisConstraintFunc,AfterErgo) \ 506 \ 507 product(uintx, GCPauseIntervalMillis, 0, \ 508 "Time slice for MMU specification") \ 509 constraint(GCPauseIntervalMillisConstraintFunc,AfterErgo) \ 510 \ 511 product(uintx, MaxGCMinorPauseMillis, max_uintx, \ 512 "Adaptive size policy maximum GC minor pause time goal " \ 513 "in millisecond") \ 514 range(0, max_uintx) \ 515 \ 516 product(uintx, GCTimeRatio, 99, \ 517 "Adaptive size policy application time to GC time ratio") \ 518 range(0, max_juint) \ 519 \ 520 product(uintx, AdaptiveSizeDecrementScaleFactor, 4, \ 521 "Adaptive size scale down factor for shrinking") \ 522 range(1, max_uintx) \ 523 \ 524 product(bool, UseAdaptiveSizeDecayMajorGCCost, true, \ 525 "Adaptive size decays the major cost for long major intervals") \ 526 \ 527 product(uintx, AdaptiveSizeMajorGCDecayTimeScale, 10, \ 528 "Time scale over which major costs decay") \ 529 range(0, max_uintx) \ 530 \ 531 product(uintx, MinSurvivorRatio, 3, \ 532 "Minimum ratio of young generation/survivor space size") \ 533 range(3, max_uintx) \ 534 \ 535 product(uintx, InitialSurvivorRatio, 8, \ 536 "Initial ratio of young generation/survivor space size") \ 537 range(0, max_uintx) \ 538 \ 539 product(size_t, BaseFootPrintEstimate, 256*M, \ 540 "Estimate of footprint other than Java Heap") \ 541 range(0, max_uintx) \ 542 \ 543 product(bool, UseGCOverheadLimit, true, \ 544 "Use policy to limit of proportion of time spent in GC " \ 545 "before an OutOfMemory error is thrown") \ 546 \ 547 product(uintx, GCTimeLimit, 98, \ 548 "Limit of the proportion of time spent in GC before " \ 549 "an OutOfMemoryError is thrown (used with GCHeapFreeLimit)") \ 550 range(0, 100) \ 551 \ 552 product(uintx, GCHeapFreeLimit, 2, \ 553 "Minimum percentage of free space after a full GC before an " \ 554 "OutOfMemoryError is thrown (used with GCTimeLimit)") \ 555 range(0, 100) \ 556 \ 557 develop(uintx, GCOverheadLimitThreshold, 5, \ 558 "Number of consecutive collections before gc time limit fires") \ 559 range(1, max_uintx) \ 560 \ 561 product(intx, PrefetchCopyIntervalInBytes, -1, \ 562 "How far ahead to prefetch destination area (<= 0 means off)") \ 563 range(-1, max_jint) \ 564 \ 565 product(intx, PrefetchScanIntervalInBytes, -1, \ 566 "How far ahead to prefetch scan area (<= 0 means off)") \ 567 range(-1, max_jint) \ 568 \ 569 product(intx, PrefetchFieldsAhead, -1, \ 570 "How many fields ahead to prefetch in oop scan (<= 0 means off)") \ 571 range(-1, max_jint) \ 572 \ 573 diagnostic(bool, VerifyDuringStartup, false, \ 574 "Verify memory system before executing any Java code " \ 575 "during VM initialization") \ 576 \ 577 diagnostic(bool, VerifyBeforeExit, trueInDebug, \ 578 "Verify system before exiting") \ 579 \ 580 diagnostic(bool, VerifyBeforeGC, false, \ 581 "Verify memory system before GC") \ 582 \ 583 diagnostic(bool, VerifyAfterGC, false, \ 584 "Verify memory system after GC") \ 585 \ 586 diagnostic(bool, VerifyDuringGC, false, \ 587 "Verify memory system during GC (between phases)") \ 588 \ 589 diagnostic(ccstrlist, VerifyGCType, "", \ 590 "GC type(s) to verify when Verify*GC is enabled." \ 591 "Available types are collector specific.") \ 592 \ 593 diagnostic(ccstrlist, VerifySubSet, "", \ 594 "Memory sub-systems to verify when Verify*GC flag(s) " \ 595 "are enabled. One or more sub-systems can be specified " \ 596 "in a comma separated string. Sub-systems are: " \ 597 "threads, heap, symbol_table, string_table, codecache, " \ 598 "dictionary, classloader_data_graph, metaspace, jni_handles, " \ 599 "codecache_oops") \ 600 \ 601 diagnostic(bool, GCParallelVerificationEnabled, true, \ 602 "Enable parallel memory system verification") \ 603 \ 604 diagnostic(bool, DeferInitialCardMark, false, \ 605 "When +ReduceInitialCardMarks, explicitly defer any that " \ 606 "may arise from new_pre_store_barrier") \ 607 \ 608 product(bool, UseCondCardMark, false, \ 609 "Check for already marked card before updating card table") \ 610 \ 611 diagnostic(bool, VerifyRememberedSets, false, \ 612 "Verify GC remembered sets") \ 613 \ 614 diagnostic(bool, VerifyObjectStartArray, true, \ 615 "Verify GC object start array if verify before/after") \ 616 \ 617 product(bool, DisableExplicitGC, false, \ 618 "Ignore calls to System.gc()") \ 619 \ 620 product(bool, PrintGC, false, \ 621 "Print message at garbage collection. " \ 622 "Deprecated, use -Xlog:gc instead.") \ 623 \ 624 product(bool, PrintGCDetails, false, \ 625 "Print more details at garbage collection. " \ 626 "Deprecated, use -Xlog:gc* instead.") \ 627 \ 628 develop(intx, ConcGCYieldTimeout, 0, \ 629 "If non-zero, assert that GC threads yield within this " \ 630 "number of milliseconds") \ 631 range(0, max_intx) \ 632 \ 633 notproduct(intx, ScavengeALotInterval, 1, \ 634 "Interval between which scavenge will occur with +ScavengeALot") \ 635 \ 636 notproduct(intx, FullGCALotInterval, 1, \ 637 "Interval between which full gc will occur with +FullGCALot") \ 638 \ 639 notproduct(intx, FullGCALotStart, 0, \ 640 "For which invocation to start FullGCAlot") \ 641 \ 642 notproduct(intx, FullGCALotDummies, 32*K, \ 643 "Dummy object allocated with +FullGCALot, forcing all objects " \ 644 "to move") \ 645 \ 646 /* gc parameters */ \ 647 product(size_t, MinHeapSize, 0, \ 648 "Minimum heap size (in bytes); zero means use ergonomics") \ 649 constraint(MinHeapSizeConstraintFunc,AfterErgo) \ 650 \ 651 product(size_t, InitialHeapSize, 0, \ 652 "Initial heap size (in bytes); zero means use ergonomics") \ 653 constraint(InitialHeapSizeConstraintFunc,AfterErgo) \ 654 \ 655 product(size_t, MaxHeapSize, ScaleForWordSize(96*M), \ 656 "Maximum heap size (in bytes)") \ 657 constraint(MaxHeapSizeConstraintFunc,AfterErgo) \ 658 \ 659 manageable(size_t, SoftMaxHeapSize, 0, \ 660 "Soft limit for maximum heap size (in bytes)") \ 661 constraint(SoftMaxHeapSizeConstraintFunc,AfterMemoryInit) \ 662 \ 663 product(size_t, OldSize, ScaleForWordSize(4*M), \ 664 "Initial tenured generation size (in bytes)") \ 665 range(0, max_uintx) \ 666 \ 667 product(size_t, NewSize, ScaleForWordSize(1*M), \ 668 "Initial new generation size (in bytes)") \ 669 constraint(NewSizeConstraintFunc,AfterErgo) \ 670 \ 671 product(size_t, MaxNewSize, max_uintx, \ 672 "Maximum new generation size (in bytes), max_uintx means set " \ 673 "ergonomically") \ 674 range(0, max_uintx) \ 675 \ 676 product_pd(size_t, HeapBaseMinAddress, \ 677 "OS specific low limit for heap base address") \ 678 constraint(HeapBaseMinAddressConstraintFunc,AfterErgo) \ 679 \ 680 product(size_t, PretenureSizeThreshold, 0, \ 681 "Maximum size in bytes of objects allocated in DefNew " \ 682 "generation; zero means no maximum") \ 683 range(0, max_uintx) \ 684 \ 685 product(size_t, MinTLABSize, 2*K, \ 686 "Minimum allowed TLAB size (in bytes)") \ 687 range(1, max_uintx/2) \ 688 constraint(MinTLABSizeConstraintFunc,AfterMemoryInit) \ 689 \ 690 product(size_t, TLABSize, 0, \ 691 "Starting TLAB size (in bytes); zero means set ergonomically") \ 692 constraint(TLABSizeConstraintFunc,AfterMemoryInit) \ 693 \ 694 product(size_t, YoungPLABSize, 4096, \ 695 "Size of young gen promotion LAB's (in HeapWords)") \ 696 constraint(YoungPLABSizeConstraintFunc,AfterMemoryInit) \ 697 \ 698 product(size_t, OldPLABSize, 1024, \ 699 "Size of old gen promotion LAB's (in HeapWords)") \ 700 constraint(OldPLABSizeConstraintFunc,AfterMemoryInit) \ 701 \ 702 product(uintx, TLABAllocationWeight, 35, \ 703 "Allocation averaging weight") \ 704 range(0, 100) \ 705 \ 706 /* Limit the lower bound of this flag to 1 as it is used */ \ 707 /* in a division expression. */ \ 708 product(uintx, TLABWasteTargetPercent, 1, \ 709 "Percentage of Eden that can be wasted") \ 710 range(1, 100) \ 711 \ 712 product(uintx, TLABRefillWasteFraction, 64, \ 713 "Maximum TLAB waste at a refill (internal fragmentation)") \ 714 range(1, max_juint) \ 715 \ 716 product(uintx, TLABWasteIncrement, 4, \ 717 "Increment allowed waste at slow allocation") \ 718 range(0, max_jint) \ 719 constraint(TLABWasteIncrementConstraintFunc,AfterMemoryInit) \ 720 \ 721 product(uintx, SurvivorRatio, 8, \ 722 "Ratio of eden/survivor space size") \ 723 range(1, max_uintx-2) \ 724 constraint(SurvivorRatioConstraintFunc,AfterMemoryInit) \ 725 \ 726 product(uintx, NewRatio, 2, \ 727 "Ratio of old/new generation sizes") \ 728 range(0, max_uintx-1) \ 729 \ 730 product_pd(size_t, NewSizeThreadIncrease, \ 731 "Additional size added to desired new generation size per " \ 732 "non-daemon thread (in bytes)") \ 733 range(0, max_uintx) \ 734 \ 735 product(uintx, QueuedAllocationWarningCount, 0, \ 736 "Number of times an allocation that queues behind a GC " \ 737 "will retry before printing a warning") \ 738 range(0, max_uintx) \ 739 \ 740 diagnostic(uintx, VerifyGCStartAt, 0, \ 741 "GC invoke count where +VerifyBefore/AfterGC kicks in") \ 742 range(0, max_uintx) \ 743 \ 744 diagnostic(intx, VerifyGCLevel, 0, \ 745 "Generation level at which to start +VerifyBefore/AfterGC") \ 746 range(0, 1) \ 747 \ 748 product(uintx, MaxTenuringThreshold, 15, \ 749 "Maximum value for tenuring threshold") \ 750 range(0, markWord::max_age + 1) \ 751 constraint(MaxTenuringThresholdConstraintFunc,AfterErgo) \ 752 \ 753 product(uintx, InitialTenuringThreshold, 7, \ 754 "Initial value for tenuring threshold") \ 755 range(0, markWord::max_age + 1) \ 756 constraint(InitialTenuringThresholdConstraintFunc,AfterErgo) \ 757 \ 758 product(uintx, TargetSurvivorRatio, 50, \ 759 "Desired percentage of survivor space used after scavenge") \ 760 range(0, 100) \ 761 \ 762 product(uintx, MarkSweepDeadRatio, 5, \ 763 "Percentage (0-100) of the old gen allowed as dead wood. " \ 764 "Serial mark sweep treats this as both the minimum and maximum " \ 765 "value. " \ 766 "Par compact uses a variable scale based on the density of the " \ 767 "generation and treats this as the maximum value when the heap " \ 768 "is either completely full or completely empty. Par compact " \ 769 "also has a smaller default value; see arguments.cpp.") \ 770 range(0, 100) \ 771 \ 772 product(uint, MarkSweepAlwaysCompactCount, 4, \ 773 "How often should we fully compact the heap (ignoring the dead " \ 774 "space parameters)") \ 775 range(1, max_juint) \ 776 \ 777 develop(uintx, GCExpandToAllocateDelayMillis, 0, \ 778 "Delay between expansion and allocation (in milliseconds)") \ 779 \ 780 product(uintx, GCDrainStackTargetSize, 64, \ 781 "Number of entries we will try to leave on the stack " \ 782 "during parallel gc") \ 783 range(0, max_juint) 784 785 #endif // SHARE_GC_SHARED_GC_GLOBALS_HPP