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