--- /dev/null 2018-11-30 10:10:44.238550338 +0100 +++ new/src/hotspot/share/gc/shenandoah/shenandoah_globals.hpp 2018-11-30 10:23:01.953248229 +0100 @@ -0,0 +1,417 @@ +/* + * Copyright (c) 2016, 2018, Red Hat, Inc. All rights reserved. + * + * This code is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 only, as + * published by the Free Software Foundation. + * + * This code is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License + * version 2 for more details (a copy is included in the LICENSE file that + * accompanied this code). + * + * You should have received a copy of the GNU General Public License version + * 2 along with this work; if not, write to the Free Software Foundation, + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. + * + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA + * or visit www.oracle.com if you need additional information or have any + * questions. + * + */ + +#ifndef SHARE_VM_GC_SHENANDOAH_SHENANDOAH_GLOBALS_HPP +#define SHARE_VM_GC_SHENANDOAH_SHENANDOAH_GLOBALS_HPP + +#define GC_SHENANDOAH_FLAGS(develop, \ + develop_pd, \ + product, \ + product_pd, \ + diagnostic, \ + diagnostic_pd, \ + experimental, \ + notproduct, \ + manageable, \ + product_rw, \ + lp64_product, \ + range, \ + constraint, \ + writeable) \ + \ + experimental(size_t, ShenandoahHeapRegionSize, 0, \ + "Size of the Shenandoah regions. Set to zero to detect " \ + "automatically.") \ + \ + experimental(size_t, ShenandoahTargetNumRegions, 2048, \ + "Target number of regions. We try to get around that many " \ + "regions, based on Shenandoah{Min,Max}RegionSize.") \ + \ + experimental(size_t, ShenandoahMinRegionSize, 256 * K, \ + "Minimum Shenandoah heap region size.") \ + \ + experimental(size_t, ShenandoahMaxRegionSize, 32 * M, \ + "Maximum Shenandoah heap region size.") \ + \ + experimental(intx, ShenandoahHumongousThreshold, 100, \ + "How large should the object be to get allocated in humongous " \ + "region, in percents of heap region size. This also caps the " \ + "maximum TLAB size.") \ + range(1, 100) \ + \ + experimental(ccstr, ShenandoahGCHeuristics, "adaptive", \ + "The heuristics to use in Shenandoah GC. Possible values:" \ + " *) adaptive - adapt to maintain the given amount of free heap;" \ + " *) static - start concurrent GC when static free heap " \ + " threshold and static allocation threshold are " \ + " tripped;" \ + " *) passive - do not start concurrent GC, wait for Full GC; " \ + " *) aggressive - run concurrent GC continuously, evacuate " \ + " everything;" \ + " *) compact - run GC with lower footprint target, may end up " \ + " doing continuous GC, evacuate lots of live " \ + " objects, uncommit heap aggressively;") \ + \ + experimental(ccstr, ShenandoahUpdateRefsEarly, "adaptive", \ + "Run a separate concurrent reference updating phase after" \ + "concurrent evacuation. Possible values: 'on', 'off', 'adaptive'")\ + \ + experimental(uintx, ShenandoahRefProcFrequency, 5, \ + "How often should (weak, soft, etc) references be processed. " \ + "References get processed at every Nth GC cycle. Set to zero " \ + "to disable reference processing.") \ + \ + experimental(uintx, ShenandoahUnloadClassesFrequency, 5, \ + "How often should classes get unloaded. " \ + "Class unloading is performed at every Nth GC cycle. " \ + "Set to zero to disable class unloading during concurrent GC.") \ + \ + experimental(uintx, ShenandoahGarbageThreshold, 60, \ + "Sets the percentage of garbage a region need to contain before " \ + "it can be marked for collection. Does not apply to all " \ + "heuristics.") \ + range(0,100) \ + \ + experimental(uintx, ShenandoahFreeThreshold, 10, \ + "Set the percentage of free heap at which a GC cycle is started. "\ + "Does not apply to all heuristics.") \ + range(0,100) \ + \ + experimental(uintx, ShenandoahInitFreeThreshold, 70, \ + "Initial remaining free heap threshold for learning steps in " \ + "heuristics. In percents of total heap size. Does not apply to " \ + "all heuristics.") \ + range(0,100) \ + \ + experimental(uintx, ShenandoahMinFreeThreshold, 10, \ + "Minimum remaining free space threshold, after which collection " \ + "definitely triggers. Does not apply to all heuristics.") \ + range(0,100) \ + \ + experimental(uintx, ShenandoahAllocationThreshold, 0, \ + "Set percentage of memory allocated since last GC cycle before " \ + "a new GC cycle can be started. Set to zero to effectively " \ + "disable.") \ + range(0,100) \ + \ + experimental(uintx, ShenandoahLearningSteps, 5, \ + "Number of GC cycles to run in order to learn application " \ + "and GC performance for adaptive heuristics.") \ + range(0,100) \ + \ + experimental(uintx, ShenandoahImmediateThreshold, 90, \ + "If mark identifies more than this much immediate garbage " \ + "regions, it shall recycle them, and shall not continue the " \ + "rest of the GC cycle. The value is in percents of total " \ + "number of candidate regions for collection set. Setting this " \ + "threshold to 100% effectively disables this shortcut.") \ + range(0,100) \ + \ + experimental(uintx, ShenandoahMergeUpdateRefsMinGap, 100, \ + "If GC is currently running in separate update-refs mode " \ + "this numbers gives the threshold when to switch to " \ + "merged update-refs mode. Number is percentage relative to" \ + "duration(marking)+duration(update-refs).") \ + \ + experimental(uintx, ShenandoahMergeUpdateRefsMaxGap, 200, \ + "If GC is currently running in merged update-refs mode " \ + "this numbers gives the threshold when to switch to " \ + "separate update-refs mode. Number is percentage relative " \ + "to duration(marking)+duration(update-refs).") \ + \ + experimental(uintx, ShenandoahGuaranteedGCInterval, 5*60*1000, \ + "Adaptive and dynamic heuristics would guarantee a GC cycle " \ + "at least with this interval. This is useful when large idle" \ + " intervals are present, where GC can run without stealing " \ + "time from active application. Time is in milliseconds.") \ + \ + experimental(bool, ShenandoahAlwaysClearSoftRefs, false, \ + "Clear soft references always, instead of using any smart " \ + "cleanup policy. This minimizes footprint at expense of more " \ + "softref churn in applications.") \ + \ + experimental(bool, ShenandoahUncommit, true, \ + "Allow Shenandoah to uncommit unused memory.") \ + \ + experimental(uintx, ShenandoahUncommitDelay, 5*60*1000, \ + "Shenandoah would start to uncommit memory for regions that were" \ + " not used for more than this time. First use after that would " \ + "incur allocation stalls. Actively used regions would never be " \ + "uncommitted, because they never decay. Time is in milliseconds." \ + "Setting this delay to 0 effectively makes Shenandoah to " \ + "uncommit the regions almost immediately.") \ + \ + experimental(bool, ShenandoahRegionSampling, false, \ + "Turns on heap region sampling via JVMStat") \ + \ + experimental(int, ShenandoahRegionSamplingRate, 40, \ + "Sampling rate for heap region sampling. " \ + "Number of milliseconds between samples") \ + \ + experimental(uintx, ShenandoahControlIntervalMin, 1, \ + "The minumum sleep interval for control loop that drives " \ + "the cycles. Lower values would increase GC responsiveness " \ + "to changing heap conditions, at the expense of higher perf " \ + "overhead. Time is in milliseconds.") \ + \ + experimental(uintx, ShenandoahControlIntervalMax, 10, \ + "The maximum sleep interval for control loop that drives " \ + "the cycles. Lower values would increase GC responsiveness " \ + "to changing heap conditions, at the expense of higher perf " \ + "overhead. Time is in milliseconds.") \ + \ + experimental(uintx, ShenandoahControlIntervalAdjustPeriod, 1000, \ + "The time period for one step in control loop interval " \ + "adjustment. Lower values make adjustments faster, at the " \ + "expense of higher perf overhead. Time is in milliseconds.") \ + \ + diagnostic(bool, ShenandoahVerify, false, \ + "Verify the Shenandoah garbage collector") \ + \ + diagnostic(intx, ShenandoahVerifyLevel, 4, \ + "Shenandoah verification level: " \ + "0 = basic heap checks; " \ + "1 = previous level, plus basic region checks; " \ + "2 = previous level, plus all roots; " \ + "3 = previous level, plus all reachable objects; " \ + "4 = previous level, plus all marked objects") \ + \ + diagnostic(bool, ShenandoahElasticTLAB, true, \ + "Use Elastic TLABs with Shenandoah") \ + \ + diagnostic(bool, ShenandoahAllowMixedAllocs, true, \ + "Allow mixing mutator and collector allocations in a single " \ + "region") \ + \ + experimental(uintx, ShenandoahAllocSpikeFactor, 5, \ + "The amount of heap space to reserve for absorbing the " \ + "allocation spikes. Larger value wastes more memory in " \ + "non-emergency cases, but provides more safety in emergency " \ + "cases. In percents of total heap size.") \ + range(0,100) \ + \ + experimental(uintx, ShenandoahEvacReserve, 5, \ + "Maximum amount of free space to reserve for evacuation. " \ + "Larger values make GC more aggressive, while leaving less " \ + "headroom for application to allocate in. " \ + "In percents of total heap size.") \ + range(1,100) \ + \ + experimental(double, ShenandoahEvacWaste, 1.2, \ + "How much waste evacuations produce within the reserved " \ + "space. Larger values make evacuations more resilient " \ + "against allocation failures, at expense of smaller csets " \ + "on each cycle.") \ + range(1.0,100.0) \ + \ + experimental(bool, ShenandoahEvacReserveOverflow, true, \ + "Allow evacuations to overflow the reserved space. " \ + "Enabling it will make evacuations more resilient when " \ + "evacuation reserve/waste is incorrect, at the risk that " \ + "application allocations run out of memory too early.") \ + \ + diagnostic(bool, ShenandoahAllocationTrace, false, \ + "Trace allocation latencies and stalls. Can be expensive when " \ + "lots of allocations happen, and may introduce scalability " \ + "bottlenecks.") \ + \ + diagnostic(intx, ShenandoahAllocationStallThreshold, 10000, \ + "When allocation tracing is enabled, the allocation stalls " \ + "larger than this threshold would be reported as warnings. " \ + "Time is in microseconds.") \ + \ + experimental(uintx, ShenandoahEvacAssist, 10, \ + "How many objects to evacuate on WB assist path. " \ + "Use zero to disable.") \ + \ + experimental(bool, ShenandoahPacing, true, \ + "Pace application allocations to give GC chance to start " \ + "and complete before allocation failure is reached.") \ + \ + experimental(uintx, ShenandoahPacingMaxDelay, 10, \ + "Max delay for pacing application allocations. " \ + "Time is in milliseconds.") \ + \ + experimental(uintx, ShenandoahPacingIdleSlack, 2, \ + "Percent of heap counted as non-taxable allocations during idle. "\ + "Larger value makes the pacing milder during idle phases, " \ + "requiring less rendezvous with control thread. Lower value " \ + "makes the pacing control less responsive to out-of-cycle allocs.")\ + range(0, 100) \ + \ + experimental(uintx, ShenandoahPacingCycleSlack, 10, \ + "Percent of free space taken as non-taxable allocations during " \ + "the GC cycle. Larger value makes the pacing milder at the " \ + "beginning of the GC cycle. Lower value makes the pacing less " \ + "uniform during the cycle.") \ + range(0, 100) \ + \ + experimental(double, ShenandoahPacingSurcharge, 1.1, \ + "Additional pacing tax surcharge to help unclutter the heap. " \ + "Larger values makes the pacing more aggressive. Lower values " \ + "risk GC cycles finish with less memory than were available at " \ + "the beginning of it.") \ + range(1.0, 100.0) \ + \ + experimental(uintx, ShenandoahCriticalFreeThreshold, 1, \ + "Percent of heap that needs to be free after recovery cycles, " \ + "either Degenerated or Full GC. If this much space is not " \ + "available, next recovery step would triggered.") \ + range(0, 100) \ + \ + diagnostic(bool, ShenandoahDegeneratedGC, true, \ + "Use Degenerated GC as the graceful degradation step. Disabling " \ + "this leads to degradation to Full GC") \ + \ + experimental(uintx, ShenandoahFullGCThreshold, 3, \ + "How many back-to-back Degenerated GCs to do before triggering " \ + "a Full GC.") \ + \ + experimental(bool, ShenandoahImplicitGCInvokesConcurrent, false, \ + "Should internally-caused GCs invoke concurrent cycles, or go to" \ + "stop-the-world (degenerated/full)?") \ + \ + experimental(bool, ShenandoahHumongousMoves, true, \ + "Allow moving humongous regions. This makes GC more resistant " \ + "to external fragmentation that may otherwise fail other " \ + "humongous allocations, at the expense of higher GC copying " \ + "costs.") \ + \ + diagnostic(bool, ShenandoahOOMDuringEvacALot, false, \ + "Simulate OOM during evacuation frequently.") \ + \ + diagnostic(bool, ShenandoahAllocFailureALot, false, \ + "Make lots of artificial allocation failures.") \ + \ + diagnostic(bool, ShenandoahTerminationTrace, false, \ + "Tracing task termination timings") \ + \ + develop(bool, ShenandoahVerifyObjectEquals, false, \ + "Verify that == and != are not used on oops. Only in fastdebug") \ + \ + diagnostic(bool, ShenandoahAlwaysPreTouch, false, \ + "Pre-touch heap memory, overrides global AlwaysPreTouch") \ + \ + experimental(intx, ShenandoahMarkScanPrefetch, 32, \ + "How many objects to prefetch ahead when traversing mark bitmaps."\ + "Set to 0 to disable prefetching.") \ + range(0, 256) \ + \ + experimental(uintx, ShenandoahMarkLoopStride, 1000, \ + "How many items are processed during one marking step") \ + \ + experimental(uintx, ShenandoahParallelRegionStride, 1024, \ + "How many regions are processed in one stride during parallel " \ + "iteration.") \ + \ + experimental(size_t, ShenandoahSATBBufferSize, 1 * K, \ + "Number of entries in an SATB log buffer.") \ + range(1, max_uintx) \ + \ + experimental(uintx, ShenandoahSATBBufferFlushInterval, 100, \ + "Forcefully flush non-empty SATB buffers at this interval. " \ + "Time is in milliseconds.") \ + \ + experimental(uint, ShenandoahParallelSafepointThreads, 4, \ + "Number of parallel threads used for safepoint prolog/epilog") \ + \ + experimental(bool, ShenandoahPreclean, true, \ + "Do concurrent preclean phase before final mark: process " \ + "definitely alive references to avoid dealing with them during " \ + "pause.") \ + \ + experimental(bool, ShenandoahSuspendibleWorkers, false, \ + "Suspend concurrent GC worker threads at safepoints") \ + \ + diagnostic(bool, ShenandoahSATBBarrier, true, \ + "Turn on/off SATB barriers in Shenandoah") \ + \ + diagnostic(bool, ShenandoahKeepAliveBarrier, true, \ + "Turn on/off keep alive barriers in Shenandoah") \ + \ + diagnostic(bool, ShenandoahWriteBarrier, true, \ + "Turn on/off write barriers in Shenandoah") \ + \ + diagnostic(bool, ShenandoahReadBarrier, true, \ + "Turn on/off read barriers in Shenandoah") \ + \ + diagnostic(bool, ShenandoahStoreValEnqueueBarrier, false, \ + "Turn on/off enqueuing of oops for storeval barriers") \ + \ + diagnostic(bool, ShenandoahStoreValReadBarrier, true, \ + "Turn on/off store val read barriers in Shenandoah") \ + \ + diagnostic(bool, ShenandoahCASBarrier, true, \ + "Turn on/off CAS barriers in Shenandoah") \ + \ + diagnostic(bool, ShenandoahAcmpBarrier, true, \ + "Turn on/off acmp barriers in Shenandoah") \ + \ + diagnostic(bool, ShenandoahCloneBarrier, true, \ + "Turn on/off clone barriers in Shenandoah") \ + \ + diagnostic(bool, ShenandoahStoreCheck, false, \ + "Emit additional code that checks objects are written to only" \ + " in to-space") \ + \ + experimental(bool, ShenandoahConcurrentScanCodeRoots, true, \ + "Scan code roots concurrently, instead of during a pause") \ + \ + experimental(uintx, ShenandoahCodeRootsStyle, 2, \ + "Use this style to scan code cache:" \ + " 0 - sequential iterator;" \ + " 1 - parallel iterator;" \ + " 2 - parallel iterator with cset filters;") \ + \ + experimental(bool, ShenandoahOptimizeStaticFinals, true, \ + "Optimize barriers on static final fields. " \ + "Turn it off for maximum compatibility with reflection or JNI " \ + "code that manipulates final fields.") \ + \ + experimental(bool, ShenandoahOptimizeInstanceFinals, false, \ + "Optimize barriers on final instance fields." \ + "Turn it off for maximum compatibility with reflection or JNI " \ + "code that manipulates final fields.") \ + \ + experimental(bool, ShenandoahOptimizeStableFinals, false, \ + "Optimize barriers on stable fields." \ + "Turn it off for maximum compatibility with reflection or JNI " \ + "code that manipulates final fields.") \ + \ + diagnostic(bool, ShenandoahDecreaseRegisterPressure, false, \ + "Try to reuse after-barrier values to reduce register pressure") \ + \ + experimental(bool, ShenandoahCommonGCStateLoads, false, \ + "Enable commonming for GC state loads in generated code.") \ + \ + develop(bool, ShenandoahVerifyOptoBarriers, false, \ + "Verify no missing barriers in C2") \ + \ + experimental(bool, ShenandoahDontIncreaseWBFreq, true, \ + "Common 2 WriteBarriers or WriteBarrier and a ReadBarrier only " \ + "if the resulting WriteBarrier isn't executed more frequently") \ + \ + experimental(bool, ShenandoahLoopOptsAfterExpansion, true, \ + "Attempt more loop opts after write barrier expansion") \ + +#endif // SHARE_VM_GC_SHENANDOAH_SHENANDOAH_GLOBALS_HPP