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