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