1 /* 2 * Copyright (c) 2016, Red Hat, Inc. and/or its affiliates. 3 * 4 * This code is free software; you can redistribute it and/or modify it 5 * under the terms of the GNU General Public License version 2 only, as 6 * published by the Free Software Foundation. 7 * 8 * This code is distributed in the hope that it will be useful, but WITHOUT 9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 11 * version 2 for more details (a copy is included in the LICENSE file that 12 * accompanied this code). 13 * 14 * You should have received a copy of the GNU General Public License version 15 * 2 along with this work; if not, write to the Free Software Foundation, 16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 17 * 18 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 19 * or visit www.oracle.com if you need additional information or have any 20 * questions. 21 * 22 */ 23 24 #ifndef SHARE_VM_GC_SHENANDOAH_SHENANDOAH_GLOBALS_HPP 25 #define SHARE_VM_GC_SHENANDOAH_SHENANDOAH_GLOBALS_HPP 26 27 #include "runtime/globals.hpp" 28 29 #define SHENANDOAH_FLAGS(develop, \ 30 develop_pd, \ 31 product, \ 32 product_pd, \ 33 diagnostic, \ 34 experimental, \ 35 notproduct, \ 36 manageable, \ 37 product_rw, \ 38 range, \ 39 constraint, \ 40 writeable) \ 41 \ 42 product(bool, UseShenandoahGC, false, \ 43 "Use the Shenandoah garbage collector") \ 44 \ 45 product(bool, ShenandoahOptimizeFinals, true, \ 46 "Optimize barriers on final and stable fields/arrays. " \ 47 "Turn it off for maximum compatibility with reflection or JNI " \ 48 "code that manipulates final fields." \ 49 "Defaults to true. ") \ 50 \ 51 product(size_t, ShenandoahHeapRegionSize, 0, \ 52 "Size of the Shenandoah regions. " \ 53 "Determined automatically by default.") \ 54 \ 55 experimental(size_t, ShenandoahMinRegionSize, 256 * K, \ 56 "Minimum heap region size. ") \ 57 \ 58 experimental(size_t, ShenandoahMaxRegionSize, 32 * M, \ 59 "Maximum heap region size. ") \ 60 \ 61 experimental(size_t, ShenandoahTargetNumRegions, 2048, \ 62 "Target number of regions. We try to get around that many " \ 63 "regions, based on ShenandoahMinRegionSize and " \ 64 "ShenandoahMaxRegionSizeSize. ") \ 65 \ 66 product(bool, UseShenandoahMatrix, false, \ 67 "Keep a connection matrix and use this to drive collection sets") \ 68 \ 69 product(bool, PrintShenandoahMatrix, false, \ 70 "Print connection matrix after marking") \ 71 \ 72 product(ccstr, ShenandoahGCHeuristics, "adaptive", \ 73 "The heuristics to use in Shenandoah GC. Possible values:" \ 74 " *) adaptive - adapt to maintain the given amount of free heap;" \ 75 " *) dynamic - start concurrent GC based on amount of free heap,"\ 76 " allocation threshold, etc;" \ 77 " *) passive - do not start concurrent GC, wait for Full GC; " \ 78 " *) aggressive - run concurrent GC continuously, evacuate " \ 79 " everything;" \ 80 " *) connected - run partial cycles focusing on least connected " \ 81 " regions, along with adaptive concurrent GC;" \ 82 " *) generational - run partial cycles focusing on young regions,"\ 83 " along with adaptive concurrent GC), " \ 84 " *) LRU - run partial cycles focusing on old regions, along" \ 85 " with adaptive concurrent GC." \ 86 "Defaults to adaptive") \ 87 \ 88 experimental(ccstr, ShenandoahUpdateRefsEarly, "adaptive", \ 89 "Run a separate concurrent reference updating phase after" \ 90 "concurrent evacuation. Possible values: 'on', 'off', 'adaptive'")\ 91 \ 92 product(uintx, ShenandoahRefProcFrequency, 5, \ 93 "How often should (weak, soft, etc) references be processed. " \ 94 "References get processed at every Nth GC cycle. " \ 95 "Set to 0 to disable reference processing. " \ 96 "Defaults to process references every 5 cycles.") \ 97 \ 98 product(uintx, ShenandoahUnloadClassesFrequency, 5, \ 99 "How often should classes get unloaded. " \ 100 "Class unloading is performed at every Nth GC cycle. " \ 101 "Set to 0 to disable concurrent class unloading. " \ 102 "Defaults to unload classes every 5 cycles.") \ 103 \ 104 experimental(uintx, ShenandoahFullGCThreshold, 3, \ 105 "How many cycles in a row to do degenerated marking on " \ 106 "cancelled GC before triggering a full-gc" \ 107 "Defaults to 3") \ 108 writeable(Always) \ 109 \ 110 product_rw(uintx, ShenandoahGarbageThreshold, 60, \ 111 "Sets the percentage of garbage a region need to contain before " \ 112 "it can be marked for collection. Applies to " \ 113 "Shenandoah GC dynamic Heuristic mode only (ignored otherwise). " \ 114 "Defaults to 60%.") \ 115 range(0,100) \ 116 \ 117 product_rw(uintx, ShenandoahFreeThreshold, 10, \ 118 "Set the percentage of free heap at which a GC cycle is started. " \ 119 "Applies to Shenandoah GC dynamic Heuristic mode only " \ 120 "(ignored otherwise). Defaults to 10%.") \ 121 range(0,100) \ 122 \ 123 product_rw(uintx, ShenandoahCSetThreshold, 40, \ 124 "Set the approximate target percentage of the heap for the" \ 125 "collection set. Defaults to 40%.") \ 126 range(0,100) \ 127 \ 128 product_rw(uintx, ShenandoahAllocationThreshold, 0, \ 129 "Set percentage of memory allocated since last GC cycle before " \ 130 "a new GC cycle is started. " \ 131 "Applies to Shenandoah GC dynamic Heuristic mode only " \ 132 "(ignored otherwise). Defauls to 0%.") \ 133 range(0,100) \ 134 \ 135 product_rw(uintx, ShenandoahGenerationalYoungGenPercentage, 20, \ 136 "Percentage of the heap designated as young") \ 137 range(0,100) \ 138 \ 139 product_rw(uintx, ShenandoahLRUOldGenPercentage, 20, \ 140 "Percentage of the heap designated as old") \ 141 range(0,100) \ 142 \ 143 product_rw(uintx, ShenandoahConnectednessPercentage, 20, \ 144 "Percentage of the heap designated for connectedness") \ 145 range(0,100) \ 146 \ 147 experimental(uintx, ShenandoahMergeUpdateRefsMinGap, 100, \ 148 "If GC is currently running in separate update-refs mode " \ 149 "this numbers gives the threshold when to switch to " \ 150 "merged update-refs mode. Number is percentage relative to" \ 151 "duration(marking)+duration(update-refs).") \ 152 writeable(Always) \ 153 \ 154 experimental(uintx, ShenandoahMergeUpdateRefsMaxGap, 200, \ 155 "If GC is currently running in merged update-refs mode " \ 156 "this numbers gives the threshold when to switch to " \ 157 "separate update-refs mode. Number is percentage relative " \ 158 "to duration(marking)+duration(update-refs).") \ 159 writeable(Always) \ 160 \ 161 experimental(double, ShenandoahGCWorkerPerJavaThread, 0.5, \ 162 "Set GC worker to Java thread ratio when " \ 163 "UseDynamicNumberOfGCThreads is enabled") \ 164 range(0.1,10.0) \ 165 \ 166 experimental(uintx, ShenandoahInitFreeThreshold, 30, \ 167 "Initial remaining free threshold for adaptive heuristics") \ 168 range(0,100) \ 169 \ 170 experimental(uintx, ShenandoahMinFreeThreshold, 3, \ 171 "Minimum remaining free threshold for adaptive heuristics") \ 172 range(0,100) \ 173 \ 174 experimental(uintx, ShenandoahMaxFreeThreshold, 70, \ 175 "Maximum remaining free threshold for adaptive heuristics") \ 176 range(0,100) \ 177 \ 178 experimental(uintx, ShenandoahImmediateThreshold, 90, \ 179 "If mark identifies more than this much immediate garbage " \ 180 "regions, it shall recycle them, and shall not continue the "\ 181 "rest of the GC cycle. The value is in percents of total " \ 182 "number of candidates for collection set. Setting this " \ 183 "threshold to 100% effectively disables this shortcut.") \ 184 range(0,100) \ 185 \ 186 experimental(uintx, ShenandoahGuaranteedGCInterval, 5*60*1000, \ 187 "Adaptive and dynamic heuristics would guarantee a GC cycle "\ 188 "at least with this interval. This is useful when large idle"\ 189 " intervals are present, where GC can run without stealing " \ 190 "time from active application. Time is in milliseconds.") \ 191 \ 192 experimental(uintx, ShenandoahHappyCyclesThreshold, 3, \ 193 "How many successful marking cycles before improving free " \ 194 "threshold for adaptive heuristics") \ 195 \ 196 experimental(uintx, ShenandoahPartialInboundThreshold, 10, \ 197 "Specifies how many inbound regions a region can have maximum " \ 198 "to be considered for collection set in partial collections.") \ 199 writeable(Always) \ 200 \ 201 experimental(uintx, ShenandoahMarkLoopStride, 1000, \ 202 "How many items are processed during one marking step") \ 203 \ 204 experimental(bool, ShenandoahConcurrentScanCodeRoots, true, \ 205 "Scan code roots concurrently, instead of during a pause") \ 206 \ 207 experimental(bool, ShenandoahConcurrentEvacCodeRoots, false, \ 208 "Evacuate code roots concurrently, instead of during a pause. " \ 209 "This requires ShenandoahBarriersForConst to be enabled.") \ 210 \ 211 experimental(uintx, ShenandoahCodeRootsStyle, 1, \ 212 "Use this style to scan code cache:" \ 213 " 0 - sequential iterator;" \ 214 " 1 - parallel iterator;" \ 215 " 2 - parallel iterator with filters;") \ 216 \ 217 experimental(uintx, ShenandoahUncommitDelay, 5*60*1000, \ 218 "Shenandoah would start to uncommit memory for regions that were"\ 219 " not used for more than this time. First use after that would " \ 220 "incur allocation stalls. Actively used regions would never be " \ 221 "uncommitted, because they never decay. Time is in milliseconds."\ 222 "Setting this delay to 0 effectively makes Shenandoah to " \ 223 "uncommit the regions almost immediately.") \ 224 \ 225 experimental(bool, ShenandoahBarriersForConst, false, \ 226 "Emit barriers for constant oops in generated code, improving " \ 227 "throughput. If no barriers are emitted, GC will need to " \ 228 "pre-evacuate code roots before returning from STW, adding to " \ 229 "pause time.") \ 230 \ 231 experimental(bool, ShenandoahDontIncreaseWBFreq, true, \ 232 "Common 2 WriteBarriers or WriteBarrier and a ReadBarrier only " \ 233 "if the resulting WriteBarrier isn't executed more frequently") \ 234 \ 235 experimental(bool, ShenandoahNoLivenessFullGC, true, \ 236 "Skip liveness counting for mark during full GC.") \ 237 \ 238 experimental(bool, ShenandoahWriteBarrierToIR, true, \ 239 "Convert write barrier to IR instead of using assembly blob") \ 240 \ 241 experimental(bool, ShenandoahWriteBarrierCsetTestInIR, true, \ 242 "Perform cset test in IR rather than in the stub") \ 243 \ 244 experimental(bool, ShenandoahLoopOptsAfterExpansion, true, \ 245 "Attempt more loop opts after write barrier expansion") \ 246 \ 247 experimental(bool, UseShenandoahOWST, true, \ 248 "Use Shenandoah work stealing termination protocol") \ 249 \ 250 experimental(size_t, ShenandoahSATBBufferSize, 1 * K, \ 251 "Number of entries in an SATB log buffer.") \ 252 range(1, max_uintx) \ 253 \ 254 experimental(int, ShenandoahRegionSamplingRate, 40, \ 255 "Sampling rate for heap region sampling. " \ 256 "Number of milliseconds between samples") \ 257 writeable(Always) \ 258 \ 259 experimental(bool, ShenandoahRegionSampling, false, \ 260 "Turns on heap region sampling via JVMStat") \ 261 writeable(Always) \ 262 \ 263 experimental(bool, ShenandoahReduceStoreValBarrier, false, \ 264 "If true, only execute storeval barrier when updating " \ 265 "references.") \ 266 \ 267 experimental(bool, ShenandoahFastSyncRoots, true, \ 268 "Enable fast synchronizer roots scanning") \ 269 \ 270 experimental(bool, ShenandoahMergeSafepointCleanup, false, \ 271 "Do safepoint cleanup piggy-backed on thread scans") \ 272 \ 273 experimental(uint, ParallelSafepointCleanupThreads, 0, \ 274 "Number of parallel threads used for safepoint cleanup") \ 275 \ 276 experimental(bool, ShenandoahPreclean, true, \ 277 "Do preclean phase before final mark") \ 278 \ 279 experimental(bool, ShenandoahSuspendibleWorkers, false, \ 280 "Suspend concurrent GC worker threads at safepoints") \ 281 \ 282 diagnostic(bool, ShenandoahSATBBarrier, true, \ 283 "Turn on/off SATB barriers in Shenandoah") \ 284 \ 285 diagnostic(bool, ShenandoahKeepAliveBarrier, true, \ 286 "Turn on/off SATB barriers in Shenandoah") \ 287 \ 288 diagnostic(bool, ShenandoahWriteBarrier, true, \ 289 "Turn on/off write barriers in Shenandoah") \ 290 \ 291 diagnostic(bool, ShenandoahReadBarrier, true, \ 292 "Turn on/off read barriers in Shenandoah") \ 293 \ 294 diagnostic(bool, ShenandoahStoreValBarrier, true, \ 295 "Turn on/off store val barriers in Shenandoah") \ 296 \ 297 diagnostic(bool, ShenandoahCASBarrier, true, \ 298 "Turn on/off CAS barriers in Shenandoah") \ 299 \ 300 diagnostic(bool, ShenandoahAcmpBarrier, true, \ 301 "Turn on/off acmp barriers in Shenandoah") \ 302 \ 303 diagnostic(bool, ShenandoahCloneBarrier, true, \ 304 "Turn on/off clone barriers in Shenandoah") \ 305 \ 306 diagnostic(bool, ShenandoahStoreCheck, false, \ 307 "Emit additional code that checks objects are written to only" \ 308 " in to-space") \ 309 \ 310 diagnostic(bool, ShenandoahVerify, false, \ 311 "Verify the Shenandoah garbage collector") \ 312 \ 313 diagnostic(intx, ShenandoahVerifyLevel, 4, \ 314 "Shenandoah verification level: " \ 315 "0 = basic heap checks; " \ 316 "1 = previous level, plus basic region checks; " \ 317 "2 = previous level, plus all roots; " \ 318 "3 = previous level, plus all reachable objects; " \ 319 "4 = previous level, plus all marked objects") \ 320 \ 321 diagnostic(bool, ShenandoahAllocationTrace, false, \ 322 "Trace allocation latencies and stalls. Can be expensive when " \ 323 "lots of allocations happen, and may introduce scalability " \ 324 "bottlenecks.") \ 325 \ 326 diagnostic(intx, ShenandoahAllocationStallThreshold, 10000, \ 327 "When allocation tracing is enabled, the allocation stalls " \ 328 "larger than this threshold would be reported as warnings. " \ 329 "Time is in microseconds.") \ 330 \ 331 diagnostic(bool, ShenandoahAsmWB, true, \ 332 "Enable/disable inline assembler write barrier code.") \ 333 \ 334 develop(bool, VerifyStrictOopOperations, false, \ 335 "Verify that == and != are not used on oops. Only in fastdebug") \ 336 \ 337 develop(bool, ShenandoahVerifyOptoBarriers, false, \ 338 "Verify no missing barriers in c2") \ 339 \ 340 develop(int, ShenandoahFailHeapExpansionAfter, -1, \ 341 "Artificially fails heap expansion after specified times." \ 342 "Used to verify allocation handling. Default -1 to disable it.") \ 343 \ 344 product(bool, ShenandoahAlwaysPreTouch, false, \ 345 "Pre-touch heap memory, overrides global AlwaysPreTouch") \ 346 \ 347 experimental(intx, ShenandoahMarkScanPrefetch, 32, \ 348 "How many objects to prefetch ahead when traversing mark bitmaps." \ 349 "Set to 0 to disable prefetching.") \ 350 range(0, 256) \ 351 \ 352 experimental(intx, ShenandoahFullGCTries, 3, \ 353 "How many times to try to do Full GC on allocation failure." \ 354 "Set to 0 to never try, and fail instead.") \ 355 range(0, 16) \ 356 357 358 SHENANDOAH_FLAGS(DECLARE_DEVELOPER_FLAG, \ 359 DECLARE_PD_DEVELOPER_FLAG, \ 360 DECLARE_PRODUCT_FLAG, \ 361 DECLARE_PD_PRODUCT_FLAG, \ 362 DECLARE_DIAGNOSTIC_FLAG, \ 363 DECLARE_EXPERIMENTAL_FLAG, \ 364 DECLARE_NOTPRODUCT_FLAG, \ 365 DECLARE_MANAGEABLE_FLAG, \ 366 DECLARE_PRODUCT_RW_FLAG, \ 367 IGNORE_RANGE, \ 368 IGNORE_CONSTRAINT, \ 369 IGNORE_WRITEABLE) 370 371 #endif // SHARE_VM_GC_SHENANDOAH_SHENANDOAH_GLOBALS_HPP