1 /*
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   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
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  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
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  24 
  25 #ifndef SHARE_GC_G1_G1_GLOBALS_HPP
  26 #define SHARE_GC_G1_G1_GLOBALS_HPP
  27 
  28 #include "runtime/globals_shared.hpp"
  29 
  30 //
  31 // Declare all globals flags used by the garbage-first compiler.
  32 //
  33 
  34 #include "utilities/macros.hpp"
  35 #if INCLUDE_G1GC
  36 #include "runtime/flags/jvmFlag.hpp"
  37 PRODUCT_FLAG(bool,     G1UseAdaptiveIHOP, true, JVMFlag::DEFAULT,
  38                        "Adaptively adjust the initiating heap occupancy from the "
  39                        "initial value of InitiatingHeapOccupancyPercent. The policy "
  40                        "attempts to start marking in time based on application "
  41                        "behavior.");
  42 
  43 PRODUCT_FLAG(size_t,   G1AdaptiveIHOPNumInitialSamples, 3, JVMFlag::EXPERIMENTAL | JVMFlag::RANGE,
  44                        "How many completed time periods from initial mark to first "
  45                        "mixed gc are required to use the input values for prediction "
  46                        "of the optimal occupancy to start marking.");
  47    FLAG_RANGE(         G1AdaptiveIHOPNumInitialSamples, 1, max_intx);
  48 
  49 PRODUCT_FLAG(uintx,    G1ConfidencePercent, 50, JVMFlag::RANGE,
  50                        "Confidence level for MMU/pause predictions");
  51    FLAG_RANGE(         G1ConfidencePercent, 0, 100);
  52 
  53 PRODUCT_FLAG(intx,     G1SummarizeRSetStatsPeriod, 0, JVMFlag::DIAGNOSTIC | JVMFlag::RANGE,
  54                        "The period (in number of GCs) at which we will generate "
  55                        "update buffer processing info "
  56                        "(0 means do not periodically generate this info); "
  57                        "it also requires that logging is enabled on the trace"
  58                        "level for gc+remset");
  59    FLAG_RANGE(         G1SummarizeRSetStatsPeriod, 0, max_intx);
  60 
  61 PRODUCT_FLAG(double,   G1ConcMarkStepDurationMillis, 10.0, JVMFlag::RANGE,
  62                        "Target duration of individual concurrent marking steps "
  63                        "in milliseconds.");
  64    FLAG_RANGE(         G1ConcMarkStepDurationMillis, 1.0, DBL_MAX);
  65 
  66 PRODUCT_FLAG(uint,     G1RefProcDrainInterval, 1000, JVMFlag::RANGE,
  67                        "The number of discovered reference objects to process before "
  68                        "draining concurrent marking work queues.");
  69    FLAG_RANGE(         G1RefProcDrainInterval, 1, INT_MAX);
  70 
  71 PRODUCT_FLAG(bool,     G1UseReferencePrecleaning, true, JVMFlag::EXPERIMENTAL,
  72                        "Concurrently preclean java.lang.ref.references instances "
  73                        "before the Remark pause.");
  74 
  75 PRODUCT_FLAG(double,   G1LastPLABAverageOccupancy, 50.0, JVMFlag::EXPERIMENTAL | JVMFlag::RANGE,
  76                        "The expected average occupancy of the last PLAB in "
  77                        "percent.");
  78    FLAG_RANGE(         G1LastPLABAverageOccupancy, 0.001, 100.0);
  79 
  80 PRODUCT_FLAG(size_t,   G1SATBBufferSize, 1*K, JVMFlag::RANGE,
  81                        "Number of entries in an SATB log buffer.");
  82    FLAG_RANGE(         G1SATBBufferSize, 1, max_uintx);
  83 
  84 DEVELOP_FLAG(intx,     G1SATBProcessCompletedThreshold, 20, JVMFlag::RANGE,
  85                        "Number of completed buffers that triggers log processing.");
  86    FLAG_RANGE(         G1SATBProcessCompletedThreshold, 0, max_jint);
  87 
  88 PRODUCT_FLAG(uintx,    G1SATBBufferEnqueueingThresholdPercent, 60, JVMFlag::RANGE,
  89                        "Before enqueueing them, each mutator thread tries to do some "
  90                        "filtering on the SATB buffers it generates. If post-filtering "
  91                        "the percentage of retained entries is over this threshold "
  92                        "the buffer will be enqueued for processing. A value of 0 "
  93                        "specifies that mutator threads should not do such filtering.");
  94    FLAG_RANGE(         G1SATBBufferEnqueueingThresholdPercent, 0, 100);
  95 
  96 PRODUCT_FLAG(intx,     G1ExpandByPercentOfAvailable, 20, JVMFlag::EXPERIMENTAL | JVMFlag::RANGE,
  97                        "When expanding, % of uncommitted space to claim.");
  98    FLAG_RANGE(         G1ExpandByPercentOfAvailable, 0, 100);
  99 
 100 PRODUCT_FLAG(size_t,   G1UpdateBufferSize, 256, JVMFlag::RANGE,
 101                        "Size of an update buffer");
 102    FLAG_RANGE(         G1UpdateBufferSize, 1, NOT_LP64(32*M) LP64_ONLY(1*G));
 103 
 104 PRODUCT_FLAG(size_t,   G1ConcRefinementYellowZone, 0, JVMFlag::RANGE,
 105                        "Number of enqueued update buffers that will "
 106                        "trigger concurrent processing. Will be selected ergonomically "
 107                        "by default.");
 108    FLAG_RANGE(         G1ConcRefinementYellowZone, 0, max_intx);
 109 
 110 PRODUCT_FLAG(size_t,   G1ConcRefinementRedZone, 0, JVMFlag::RANGE,
 111                        "Maximum number of enqueued update buffers before mutator "
 112                        "threads start processing new ones instead of enqueueing them. "
 113                        "Will be selected ergonomically by default.");
 114    FLAG_RANGE(         G1ConcRefinementRedZone, 0, max_intx);
 115 
 116 PRODUCT_FLAG(size_t,   G1ConcRefinementGreenZone, 0, JVMFlag::RANGE,
 117                        "The number of update buffers that are left in the queue by the "
 118                        "concurrent processing threads. Will be selected ergonomically "
 119                        "by default.");
 120    FLAG_RANGE(         G1ConcRefinementGreenZone, 0, max_intx);
 121 
 122 PRODUCT_FLAG(uintx,    G1ConcRefinementServiceIntervalMillis, 300, JVMFlag::RANGE,
 123                        "The last concurrent refinement thread wakes up every "
 124                        "specified number of milliseconds to do miscellaneous work.");
 125    FLAG_RANGE(         G1ConcRefinementServiceIntervalMillis, 0, max_jint);
 126 
 127 PRODUCT_FLAG(size_t,   G1ConcRefinementThresholdStep, 2, JVMFlag::RANGE,
 128                        "Each time the rset update queue increases by this amount "
 129                        "activate the next refinement thread if available. "
 130                        "The actual step size will be selected ergonomically by "
 131                        "default, with this value used to determine a lower bound.");
 132    FLAG_RANGE(         G1ConcRefinementThresholdStep, 1, SIZE_MAX);
 133 
 134 PRODUCT_FLAG(intx,     G1RSetUpdatingPauseTimePercent, 10, JVMFlag::RANGE,
 135                        "A target percentage of time that is allowed to be spend on "
 136                        "process RS update buffers during the collection pause.");
 137    FLAG_RANGE(         G1RSetUpdatingPauseTimePercent, 0, 100);
 138 
 139 PRODUCT_FLAG(bool,     G1UseAdaptiveConcRefinement, true, JVMFlag::DEFAULT,
 140                        "Select green, yellow and red zones adaptively to meet the "
 141                        "the pause requirements.");
 142 
 143 PRODUCT_FLAG(size_t,   G1ConcRSLogCacheSize, 10, JVMFlag::RANGE,
 144                        "Log base 2 of the length of conc RS hot-card cache.");
 145    FLAG_RANGE(         G1ConcRSLogCacheSize, 0, 27);
 146 
 147 PRODUCT_FLAG(uintx,    G1ConcRSHotCardLimit, 4, JVMFlag::RANGE,
 148                        "The threshold that defines (>=) a hot card.");
 149    FLAG_RANGE(         G1ConcRSHotCardLimit, 0, max_jubyte);
 150 
 151 DEVELOP_FLAG(intx,     G1RSetRegionEntriesBase, 256, JVMFlag::RANGE,
 152                        "Max number of regions in a fine-grain table per MB.");
 153    FLAG_RANGE(         G1RSetRegionEntriesBase, 1, max_jint/wordSize);
 154 
 155 PRODUCT_FLAG(intx,     G1RSetRegionEntries, 0, JVMFlag::RANGE | JVMFlag::CONSTRAINT,
 156                        "Max number of regions for which we keep bitmaps."
 157                        "Will be set ergonomically by default");
 158    FLAG_RANGE(         G1RSetRegionEntries, 0, max_jint/wordSize);
 159    FLAG_CONSTRAINT(    G1RSetRegionEntries, (void*)G1RSetRegionEntriesConstraintFunc, JVMFlag::AfterErgo);
 160 
 161 DEVELOP_FLAG(intx,     G1RSetSparseRegionEntriesBase, 4, JVMFlag::RANGE,
 162                        "Max number of entries per region in a sparse table "
 163                        "per MB.");
 164    FLAG_RANGE(         G1RSetSparseRegionEntriesBase, 1, max_jint/wordSize);
 165 
 166 PRODUCT_FLAG(intx,     G1RSetSparseRegionEntries, 0, JVMFlag::RANGE | JVMFlag::CONSTRAINT,
 167                        "Max number of entries per region in a sparse table."
 168                        "Will be set ergonomically by default.");
 169    FLAG_RANGE(         G1RSetSparseRegionEntries, 0, max_jint/wordSize);
 170    FLAG_CONSTRAINT(    G1RSetSparseRegionEntries, (void*)G1RSetSparseRegionEntriesConstraintFunc, JVMFlag::AfterErgo);
 171 
 172 DEVELOP_FLAG(intx,     G1MaxVerifyFailures, -1, JVMFlag::RANGE,
 173                        "The maximum number of verification failures to print.  "
 174                        "-1 means print all.");
 175    FLAG_RANGE(         G1MaxVerifyFailures, -1, max_jint);
 176 
 177 PRODUCT_FLAG(uintx,    G1ReservePercent, 10, JVMFlag::RANGE,
 178                        "It determines the minimum reserve we should have in the heap "
 179                        "to minimize the probability of promotion failure.");
 180    FLAG_RANGE(         G1ReservePercent, 0, 50);
 181 
 182 PRODUCT_FLAG(size_t,   G1HeapRegionSize, 0, JVMFlag::RANGE | JVMFlag::CONSTRAINT,
 183                        "Size of the G1 regions.");
 184    FLAG_RANGE(         G1HeapRegionSize, 0, 32*M);
 185    FLAG_CONSTRAINT(    G1HeapRegionSize, (void*)G1HeapRegionSizeConstraintFunc, JVMFlag::AfterMemoryInit);
 186 
 187 PRODUCT_FLAG(uint,     G1ConcRefinementThreads, 0, JVMFlag::RANGE,
 188                        "The number of parallel rem set update threads. "
 189                        "Will be set ergonomically by default.");
 190    FLAG_RANGE(         G1ConcRefinementThreads, 0, (max_jint-1)/wordSize);
 191 
 192 DEVELOP_FLAG(bool,     G1VerifyCTCleanup, false, JVMFlag::DEFAULT,
 193                        "Verify card table cleanup.");
 194 
 195 DEVELOP_FLAG(uintx,    G1DummyRegionsPerGC, 0, JVMFlag::DEFAULT,
 196                        "The number of dummy regions G1 will allocate at the end of "
 197                        "each evacuation pause in order to artificially fill up the "
 198                        "heap and stress the marking implementation.");
 199 
 200 DEVELOP_FLAG(bool,     G1ExitOnExpansionFailure, false, JVMFlag::DEFAULT,
 201                        "Raise a fatal VM exit out of memory failure in the event "
 202                        " that heap expansion fails due to running out of swap.");
 203 
 204 PRODUCT_FLAG(uintx,    G1MaxNewSizePercent, 60, JVMFlag::EXPERIMENTAL | JVMFlag::RANGE | JVMFlag::CONSTRAINT,
 205                        "Percentage (0-100) of the heap size to use as default "
 206                        " maximum young gen size.");
 207    FLAG_RANGE(         G1MaxNewSizePercent, 0, 100);
 208    FLAG_CONSTRAINT(    G1MaxNewSizePercent, (void*)G1MaxNewSizePercentConstraintFunc, JVMFlag::AfterErgo);
 209 
 210 PRODUCT_FLAG(uintx,    G1NewSizePercent, 5, JVMFlag::EXPERIMENTAL | JVMFlag::RANGE | JVMFlag::CONSTRAINT,
 211                        "Percentage (0-100) of the heap size to use as default "
 212                        "minimum young gen size.");
 213    FLAG_RANGE(         G1NewSizePercent, 0, 100);
 214    FLAG_CONSTRAINT(    G1NewSizePercent, (void*)G1NewSizePercentConstraintFunc, JVMFlag::AfterErgo);
 215 
 216 PRODUCT_FLAG(uintx,    G1MixedGCLiveThresholdPercent, 85, JVMFlag::EXPERIMENTAL | JVMFlag::RANGE,
 217                        "Threshold for regions to be considered for inclusion in the "
 218                        "collection set of mixed GCs. "
 219                        "Regions with live bytes exceeding this will not be collected.");
 220    FLAG_RANGE(         G1MixedGCLiveThresholdPercent, 0, 100);
 221 
 222 PRODUCT_FLAG(uintx,    G1HeapWastePercent, 5, JVMFlag::RANGE,
 223                        "Amount of space, expressed as a percentage of the heap size, "
 224                        "that G1 is willing not to collect to avoid expensive GCs.");
 225    FLAG_RANGE(         G1HeapWastePercent, 0, 100);
 226 
 227 PRODUCT_FLAG(uintx,    G1MixedGCCountTarget, 8, JVMFlag::RANGE,
 228                        "The target number of mixed GCs after a marking cycle.");
 229    FLAG_RANGE(         G1MixedGCCountTarget, 0, max_uintx);
 230 
 231 PRODUCT_FLAG(bool,     G1EagerReclaimHumongousObjects, true, JVMFlag::EXPERIMENTAL,
 232                        "Try to reclaim dead large objects at every young GC.");
 233 
 234 PRODUCT_FLAG(bool,     G1EagerReclaimHumongousObjectsWithStaleRefs, true, JVMFlag::EXPERIMENTAL,
 235                        "Try to reclaim dead large objects that have a few stale "
 236                        "references at every young GC.");
 237 
 238 PRODUCT_FLAG(size_t,   G1RebuildRemSetChunkSize, 256 * K, JVMFlag::EXPERIMENTAL | JVMFlag::RANGE,
 239                        "Chunk size used for rebuilding the remembered set.");
 240    FLAG_RANGE(         G1RebuildRemSetChunkSize, 4 * K, 32 * M);
 241 
 242 PRODUCT_FLAG(uintx,    G1OldCSetRegionThresholdPercent, 10, JVMFlag::EXPERIMENTAL | JVMFlag::RANGE,
 243                        "An upper bound for the number of old CSet regions expressed "
 244                        "as a percentage of the heap size.");
 245    FLAG_RANGE(         G1OldCSetRegionThresholdPercent, 0, 100);
 246 
 247 NOTPROD_FLAG(bool,     G1EvacuationFailureALot, false, JVMFlag::DEFAULT,
 248                        "Force use of evacuation failure handling during certain "
 249                        "evacuation pauses");
 250 
 251 DEVELOP_FLAG(uintx,    G1EvacuationFailureALotCount, 1000, JVMFlag::DEFAULT,
 252                        "Number of successful evacuations between evacuation failures "
 253                        "occurring at object copying");
 254 
 255 DEVELOP_FLAG(uintx,    G1EvacuationFailureALotInterval, 5, JVMFlag::DEFAULT,
 256                        "Total collections between forced triggering of evacuation "
 257                        "failures");
 258 
 259 DEVELOP_FLAG(bool,     G1EvacuationFailureALotDuringConcMark, true, JVMFlag::DEFAULT,
 260                        "Force use of evacuation failure handling during evacuation "
 261                        "pauses when marking is in progress");
 262 
 263 DEVELOP_FLAG(bool,     G1EvacuationFailureALotDuringInitialMark, true, JVMFlag::DEFAULT,
 264                        "Force use of evacuation failure handling during initial mark "
 265                        "evacuation pauses");
 266 
 267 DEVELOP_FLAG(bool,     G1EvacuationFailureALotDuringYoungGC, true, JVMFlag::DEFAULT,
 268                        "Force use of evacuation failure handling during young "
 269                        "evacuation pauses");
 270 
 271 DEVELOP_FLAG(bool,     G1EvacuationFailureALotDuringMixedGC, true, JVMFlag::DEFAULT,
 272                        "Force use of evacuation failure handling during mixed "
 273                        "evacuation pauses");
 274 
 275 PRODUCT_FLAG(bool,     G1VerifyRSetsDuringFullGC, false, JVMFlag::DIAGNOSTIC,
 276                        "If true, perform verification of each heap region's "
 277                        "remembered set when verifying the heap during a full GC.");
 278 
 279 PRODUCT_FLAG(bool,     G1VerifyHeapRegionCodeRoots, false, JVMFlag::DIAGNOSTIC,
 280                        "Verify the code root lists attached to each heap region.");
 281 
 282 DEVELOP_FLAG(bool,     G1VerifyBitmaps, false, JVMFlag::DEFAULT,
 283                        "Verifies the consistency of the marking bitmaps");
 284 
 285 PRODUCT_FLAG(uintx,    G1PeriodicGCInterval, 0, JVMFlag::MANAGEABLE,
 286                        "Number of milliseconds after a previous GC to wait before "
 287                        "triggering a periodic gc. A value of zero disables periodically "
 288                        "enforced gc cycles.");
 289 
 290 PRODUCT_FLAG(bool,     G1PeriodicGCInvokesConcurrent, true, JVMFlag::DEFAULT,
 291                        "Determines the kind of periodic GC. Set to true to have G1 "
 292                        "perform a concurrent GC as periodic GC, otherwise use a STW "
 293                        "Full GC.");
 294 
 295 PRODUCT_FLAG(double,   G1PeriodicGCSystemLoadThreshold, 0.0, JVMFlag::MANAGEABLE | JVMFlag::RANGE,
 296                        "Maximum recent system wide load as returned by the 1m value "
 297                        "of getloadavg() at which G1 triggers a periodic GC. A load "
 298                        "above this value cancels a given periodic GC. A value of zero "
 299                        "disables this check.");
 300    FLAG_RANGE(         G1PeriodicGCSystemLoadThreshold, 0.0, (double)max_uintx);
 301 
 302 PRODUCT_FLAG(uintx,    G1YoungExpansionBufferPercent, 10, JVMFlag::EXPERIMENTAL | JVMFlag::RANGE,
 303                        "When heterogenous heap is enabled by AllocateOldGenAt "
 304                        "option, after every GC, young gen is re-sized which "
 305                        "involves system calls to commit/uncommit memory. To "
 306                        "reduce these calls, we keep a buffer of extra regions to "
 307                        "absorb small changes in young gen length. This flag takes "
 308                        "the buffer size as an percentage of young gen length");
 309    FLAG_RANGE(         G1YoungExpansionBufferPercent, 0, 100);
 310 #endif // INCLUDE_G1GC
 311 
 312 #endif // SHARE_GC_G1_G1_GLOBALS_HPP