# HG changeset patch # User jmasa # Date 1277420172 25200 # Node ID ea2cf3a72a660907c65f4f959bf39e02f787f3f1 # Parent 13152be884e50b6469035a3811c31d80a257a4c8# Parent b4ce504ecca8edb13cd512f3e69f6ae0892aa874 Merge diff -r 13152be884e5 -r ea2cf3a72a66 hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp --- a/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp Tue Jun 15 18:07:27 2010 -0700 +++ b/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp Thu Jun 24 15:56:12 2010 -0700 @@ -3972,6 +3972,10 @@ void work(int i) { if (i >= _n_workers) return; // no work needed this round + + double start_time_ms = os::elapsedTime() * 1000.0; + _g1h->g1_policy()->record_gc_worker_start_time(i, start_time_ms); + ResourceMark rm; HandleMark hm; @@ -4019,7 +4023,7 @@ double elapsed_ms = (os::elapsedTime()-start)*1000.0; double term_ms = pss.term_time()*1000.0; _g1h->g1_policy()->record_obj_copy_time(i, elapsed_ms-term_ms); - _g1h->g1_policy()->record_termination_time(i, term_ms); + _g1h->g1_policy()->record_termination(i, term_ms, pss.term_attempts()); } _g1h->g1_policy()->record_thread_age_table(pss.age_table()); _g1h->update_surviving_young_words(pss.surviving_young_words()+1); @@ -4043,7 +4047,8 @@ double term = pss.term_time(); gclog_or_tty->print(" Elapsed: %7.2f ms.\n" " Strong roots: %7.2f ms (%6.2f%%)\n" - " Termination: %7.2f ms (%6.2f%%) (in %d entries)\n", + " Termination: %7.2f ms (%6.2f%%) " + "(in "SIZE_FORMAT" entries)\n", elapsed * 1000.0, strong_roots * 1000.0, (strong_roots*100.0/elapsed), term * 1000.0, (term*100.0/elapsed), @@ -4059,6 +4064,8 @@ assert(pss.refs_to_scan() == 0, "Task queue should be empty"); assert(pss.overflowed_refs_to_scan() == 0, "Overflow queue should be empty"); + double end_time_ms = os::elapsedTime() * 1000.0; + _g1h->g1_policy()->record_gc_worker_end_time(i, end_time_ms); } }; diff -r 13152be884e5 -r ea2cf3a72a66 hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp --- a/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp Tue Jun 15 18:07:27 2010 -0700 +++ b/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp Thu Jun 24 15:56:12 2010 -0700 @@ -1549,7 +1549,7 @@ int _hash_seed; int _queue_num; - int _term_attempts; + size_t _term_attempts; #if G1_DETAILED_STATS int _pushes, _pops, _steals, _steal_attempts; int _overflow_pushes; @@ -1727,8 +1727,8 @@ int* hash_seed() { return &_hash_seed; } int queue_num() { return _queue_num; } - int term_attempts() { return _term_attempts; } - void note_term_attempt() { _term_attempts++; } + size_t term_attempts() { return _term_attempts; } + void note_term_attempt() { _term_attempts++; } #if G1_DETAILED_STATS int pushes() { return _pushes; } diff -r 13152be884e5 -r ea2cf3a72a66 hotspot/src/share/vm/gc_implementation/g1/g1CollectorPolicy.cpp --- a/hotspot/src/share/vm/gc_implementation/g1/g1CollectorPolicy.cpp Tue Jun 15 18:07:27 2010 -0700 +++ b/hotspot/src/share/vm/gc_implementation/g1/g1CollectorPolicy.cpp Thu Jun 24 15:56:12 2010 -0700 @@ -231,20 +231,21 @@ _recent_prev_end_times_for_all_gcs_sec->add(os::elapsedTime()); _prev_collection_pause_end_ms = os::elapsedTime() * 1000.0; + _par_last_gc_worker_start_times_ms = new double[_parallel_gc_threads]; _par_last_ext_root_scan_times_ms = new double[_parallel_gc_threads]; _par_last_mark_stack_scan_times_ms = new double[_parallel_gc_threads]; - _par_last_update_rs_start_times_ms = new double[_parallel_gc_threads]; _par_last_update_rs_times_ms = new double[_parallel_gc_threads]; _par_last_update_rs_processed_buffers = new double[_parallel_gc_threads]; - _par_last_scan_rs_start_times_ms = new double[_parallel_gc_threads]; _par_last_scan_rs_times_ms = new double[_parallel_gc_threads]; _par_last_scan_new_refs_times_ms = new double[_parallel_gc_threads]; _par_last_obj_copy_times_ms = new double[_parallel_gc_threads]; _par_last_termination_times_ms = new double[_parallel_gc_threads]; + _par_last_termination_attempts = new double[_parallel_gc_threads]; + _par_last_gc_worker_end_times_ms = new double[_parallel_gc_threads]; // start conservatively _expensive_region_limit_ms = 0.5 * (double) MaxGCPauseMillis; @@ -274,10 +275,64 @@ // - double time_slice = (double) GCPauseIntervalMillis / 1000.0; + // Below, we might need to calculate the pause time target based on + // the pause interval. When we do so we are going to give G1 maximum + // flexibility and allow it to do pauses when it needs to. So, we'll + // arrange that the pause interval to be pause time target + 1 to + // ensure that a) the pause time target is maximized with respect to + // the pause interval and b) we maintain the invariant that pause + // time target < pause interval. If the user does not want this + // maximum flexibility, they will have to set the pause interval + // explicitly. + + // First make sure that, if either parameter is set, its value is + // reasonable. + if (!FLAG_IS_DEFAULT(MaxGCPauseMillis)) { + if (MaxGCPauseMillis < 1) { + vm_exit_during_initialization("MaxGCPauseMillis should be " + "greater than 0"); + } + } + if (!FLAG_IS_DEFAULT(GCPauseIntervalMillis)) { + if (GCPauseIntervalMillis < 1) { + vm_exit_during_initialization("GCPauseIntervalMillis should be " + "greater than 0"); + } + } + + // Then, if the pause time target parameter was not set, set it to + // the default value. + if (FLAG_IS_DEFAULT(MaxGCPauseMillis)) { + if (FLAG_IS_DEFAULT(GCPauseIntervalMillis)) { + // The default pause time target in G1 is 200ms + FLAG_SET_DEFAULT(MaxGCPauseMillis, 200); + } else { + // We do not allow the pause interval to be set without the + // pause time target + vm_exit_during_initialization("GCPauseIntervalMillis cannot be set " + "without setting MaxGCPauseMillis"); + } + } + + // Then, if the interval parameter was not set, set it according to + // the pause time target (this will also deal with the case when the + // pause time target is the default value). + if (FLAG_IS_DEFAULT(GCPauseIntervalMillis)) { + FLAG_SET_DEFAULT(GCPauseIntervalMillis, MaxGCPauseMillis + 1); + } + + // Finally, make sure that the two parameters are consistent. + if (MaxGCPauseMillis >= GCPauseIntervalMillis) { + char buffer[256]; + jio_snprintf(buffer, 256, + "MaxGCPauseMillis (%u) should be less than " + "GCPauseIntervalMillis (%u)", + MaxGCPauseMillis, GCPauseIntervalMillis); + vm_exit_during_initialization(buffer); + } + double max_gc_time = (double) MaxGCPauseMillis / 1000.0; - guarantee(max_gc_time < time_slice, - "Max GC time should not be greater than the time slice"); + double time_slice = (double) GCPauseIntervalMillis / 1000.0; _mmu_tracker = new G1MMUTrackerQueue(time_slice, max_gc_time); _sigma = (double) G1ConfidencePercent / 100.0; @@ -782,16 +837,17 @@ // if they are not set properly for (int i = 0; i < _parallel_gc_threads; ++i) { - _par_last_ext_root_scan_times_ms[i] = -666.0; - _par_last_mark_stack_scan_times_ms[i] = -666.0; - _par_last_update_rs_start_times_ms[i] = -666.0; - _par_last_update_rs_times_ms[i] = -666.0; - _par_last_update_rs_processed_buffers[i] = -666.0; - _par_last_scan_rs_start_times_ms[i] = -666.0; - _par_last_scan_rs_times_ms[i] = -666.0; - _par_last_scan_new_refs_times_ms[i] = -666.0; - _par_last_obj_copy_times_ms[i] = -666.0; - _par_last_termination_times_ms[i] = -666.0; + _par_last_gc_worker_start_times_ms[i] = -1234.0; + _par_last_ext_root_scan_times_ms[i] = -1234.0; + _par_last_mark_stack_scan_times_ms[i] = -1234.0; + _par_last_update_rs_times_ms[i] = -1234.0; + _par_last_update_rs_processed_buffers[i] = -1234.0; + _par_last_scan_rs_times_ms[i] = -1234.0; + _par_last_scan_new_refs_times_ms[i] = -1234.0; + _par_last_obj_copy_times_ms[i] = -1234.0; + _par_last_termination_times_ms[i] = -1234.0; + _par_last_termination_attempts[i] = -1234.0; + _par_last_gc_worker_end_times_ms[i] = -1234.0; } #endif @@ -942,9 +998,9 @@ return sum; } -void G1CollectorPolicy::print_par_stats (int level, - const char* str, - double* data, +void G1CollectorPolicy::print_par_stats(int level, + const char* str, + double* data, bool summary) { double min = data[0], max = data[0]; double total = 0.0; @@ -973,10 +1029,10 @@ gclog_or_tty->print_cr("]"); } -void G1CollectorPolicy::print_par_buffers (int level, - const char* str, - double* data, - bool summary) { +void G1CollectorPolicy::print_par_sizes(int level, + const char* str, + double* data, + bool summary) { double min = data[0], max = data[0]; double total = 0.0; int j; @@ -1321,15 +1377,22 @@ } if (parallel) { print_stats(1, "Parallel Time", _cur_collection_par_time_ms); - print_par_stats(2, "Update RS (Start)", _par_last_update_rs_start_times_ms, false); + print_par_stats(2, "GC Worker Start Time", + _par_last_gc_worker_start_times_ms, false); print_par_stats(2, "Update RS", _par_last_update_rs_times_ms); - print_par_buffers(3, "Processed Buffers", - _par_last_update_rs_processed_buffers, true); - print_par_stats(2, "Ext Root Scanning", _par_last_ext_root_scan_times_ms); - print_par_stats(2, "Mark Stack Scanning", _par_last_mark_stack_scan_times_ms); + print_par_sizes(3, "Processed Buffers", + _par_last_update_rs_processed_buffers, true); + print_par_stats(2, "Ext Root Scanning", + _par_last_ext_root_scan_times_ms); + print_par_stats(2, "Mark Stack Scanning", + _par_last_mark_stack_scan_times_ms); print_par_stats(2, "Scan RS", _par_last_scan_rs_times_ms); print_par_stats(2, "Object Copy", _par_last_obj_copy_times_ms); print_par_stats(2, "Termination", _par_last_termination_times_ms); + print_par_sizes(3, "Termination Attempts", + _par_last_termination_attempts, true); + print_par_stats(2, "GC Worker End Time", + _par_last_gc_worker_end_times_ms, false); print_stats(2, "Other", parallel_other_time); print_stats(1, "Clear CT", _cur_clear_ct_time_ms); } else { diff -r 13152be884e5 -r ea2cf3a72a66 hotspot/src/share/vm/gc_implementation/g1/g1CollectorPolicy.hpp --- a/hotspot/src/share/vm/gc_implementation/g1/g1CollectorPolicy.hpp Tue Jun 15 18:07:27 2010 -0700 +++ b/hotspot/src/share/vm/gc_implementation/g1/g1CollectorPolicy.hpp Thu Jun 24 15:56:12 2010 -0700 @@ -171,16 +171,17 @@ double* _cur_aux_times_ms; bool* _cur_aux_times_set; + double* _par_last_gc_worker_start_times_ms; double* _par_last_ext_root_scan_times_ms; double* _par_last_mark_stack_scan_times_ms; - double* _par_last_update_rs_start_times_ms; double* _par_last_update_rs_times_ms; double* _par_last_update_rs_processed_buffers; - double* _par_last_scan_rs_start_times_ms; double* _par_last_scan_rs_times_ms; double* _par_last_scan_new_refs_times_ms; double* _par_last_obj_copy_times_ms; double* _par_last_termination_times_ms; + double* _par_last_termination_attempts; + double* _par_last_gc_worker_end_times_ms; // indicates that we are in young GC mode bool _in_young_gc_mode; @@ -559,13 +560,14 @@ } protected: - void print_stats (int level, const char* str, double value); - void print_stats (int level, const char* str, int value); - void print_par_stats (int level, const char* str, double* data) { + void print_stats(int level, const char* str, double value); + void print_stats(int level, const char* str, int value); + + void print_par_stats(int level, const char* str, double* data) { print_par_stats(level, str, data, true); } - void print_par_stats (int level, const char* str, double* data, bool summary); - void print_par_buffers (int level, const char* str, double* data, bool summary); + void print_par_stats(int level, const char* str, double* data, bool summary); + void print_par_sizes(int level, const char* str, double* data, bool summary); void check_other_times(int level, NumberSeq* other_times_ms, @@ -891,6 +893,10 @@ virtual void record_full_collection_start(); virtual void record_full_collection_end(); + void record_gc_worker_start_time(int worker_i, double ms) { + _par_last_gc_worker_start_times_ms[worker_i] = ms; + } + void record_ext_root_scan_time(int worker_i, double ms) { _par_last_ext_root_scan_times_ms[worker_i] = ms; } @@ -912,10 +918,6 @@ _all_mod_union_times_ms->add(ms); } - void record_update_rs_start_time(int thread, double ms) { - _par_last_update_rs_start_times_ms[thread] = ms; - } - void record_update_rs_time(int thread, double ms) { _par_last_update_rs_times_ms[thread] = ms; } @@ -925,10 +927,6 @@ _par_last_update_rs_processed_buffers[thread] = processed_buffers; } - void record_scan_rs_start_time(int thread, double ms) { - _par_last_scan_rs_start_times_ms[thread] = ms; - } - void record_scan_rs_time(int thread, double ms) { _par_last_scan_rs_times_ms[thread] = ms; } @@ -953,16 +951,13 @@ _par_last_obj_copy_times_ms[thread] += ms; } - void record_obj_copy_time(double ms) { - record_obj_copy_time(0, ms); + void record_termination(int thread, double ms, size_t attempts) { + _par_last_termination_times_ms[thread] = ms; + _par_last_termination_attempts[thread] = (double) attempts; } - void record_termination_time(int thread, double ms) { - _par_last_termination_times_ms[thread] = ms; - } - - void record_termination_time(double ms) { - record_termination_time(0, ms); + void record_gc_worker_end_time(int worker_i, double ms) { + _par_last_gc_worker_end_times_ms[worker_i] = ms; } void record_pause_time_ms(double ms) { diff -r 13152be884e5 -r ea2cf3a72a66 hotspot/src/share/vm/gc_implementation/g1/g1RemSet.cpp --- a/hotspot/src/share/vm/gc_implementation/g1/g1RemSet.cpp Tue Jun 15 18:07:27 2010 -0700 +++ b/hotspot/src/share/vm/gc_implementation/g1/g1RemSet.cpp Thu Jun 24 15:56:12 2010 -0700 @@ -303,7 +303,6 @@ assert( _cards_scanned != NULL, "invariant" ); _cards_scanned[worker_i] = scanRScl.cards_done(); - _g1p->record_scan_rs_start_time(worker_i, rs_time_start * 1000.0); _g1p->record_scan_rs_time(worker_i, scan_rs_time_sec * 1000.0); } @@ -311,8 +310,6 @@ ConcurrentG1Refine* cg1r = _g1->concurrent_g1_refine(); double start = os::elapsedTime(); - _g1p->record_update_rs_start_time(worker_i, start * 1000.0); - // Apply the appropriate closure to all remaining log entries. _g1->iterate_dirty_card_closure(false, worker_i); // Now there should be no dirty cards. @@ -471,7 +468,6 @@ updateRS(worker_i); scanNewRefsRS(oc, worker_i); } else { - _g1p->record_update_rs_start_time(worker_i, os::elapsedTime() * 1000.0); _g1p->record_update_rs_processed_buffers(worker_i, 0.0); _g1p->record_update_rs_time(worker_i, 0.0); _g1p->record_scan_new_refs_time(worker_i, 0.0); @@ -479,7 +475,6 @@ if (G1UseParallelRSetScanning || (worker_i == 0)) { scanRS(oc, worker_i); } else { - _g1p->record_scan_rs_start_time(worker_i, os::elapsedTime() * 1000.0); _g1p->record_scan_rs_time(worker_i, 0.0); } } else { diff -r 13152be884e5 -r ea2cf3a72a66 hotspot/src/share/vm/gc_implementation/parallelScavenge/cardTableExtension.cpp --- a/hotspot/src/share/vm/gc_implementation/parallelScavenge/cardTableExtension.cpp Tue Jun 15 18:07:27 2010 -0700 +++ b/hotspot/src/share/vm/gc_implementation/parallelScavenge/cardTableExtension.cpp Thu Jun 24 15:56:12 2010 -0700 @@ -1,5 +1,5 @@ /* - * Copyright (c) 2001, 2008, Oracle and/or its affiliates. All rights reserved. + * Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it @@ -566,14 +566,14 @@ #endif // Commit new or uncommit old pages, if necessary. - resize_commit_uncommit(changed_region, new_region); + if (resize_commit_uncommit(changed_region, new_region)) { + // Set the new start of the committed region + resize_update_committed_table(changed_region, new_region); + } // Update card table entries resize_update_card_table_entries(changed_region, new_region); - // Set the new start of the committed region - resize_update_committed_table(changed_region, new_region); - // Update the covered region resize_update_covered_table(changed_region, new_region); @@ -604,8 +604,9 @@ debug_only(verify_guard();) } -void CardTableExtension::resize_commit_uncommit(int changed_region, +bool CardTableExtension::resize_commit_uncommit(int changed_region, MemRegion new_region) { + bool result = false; // Commit new or uncommit old pages, if necessary. MemRegion cur_committed = _committed[changed_region]; assert(_covered[changed_region].end() == new_region.end(), @@ -675,20 +676,31 @@ "card table expansion"); } } + result = true; } else if (new_start_aligned > cur_committed.start()) { // Shrink the committed region +#if 0 // uncommitting space is currently unsafe because of the interactions + // of growing and shrinking regions. One region A can uncommit space + // that it owns but which is being used by another region B (maybe). + // Region B has not committed the space because it was already + // committed by region A. MemRegion uncommit_region = committed_unique_to_self(changed_region, MemRegion(cur_committed.start(), new_start_aligned)); if (!uncommit_region.is_empty()) { if (!os::uncommit_memory((char*)uncommit_region.start(), uncommit_region.byte_size())) { - vm_exit_out_of_memory(uncommit_region.byte_size(), - "card table contraction"); + // If the uncommit fails, ignore it. Let the + // committed table resizing go even though the committed + // table will over state the committed space. } } +#else + assert(!result, "Should be false with current workaround"); +#endif } assert(_committed[changed_region].end() == cur_committed.end(), "end should not change"); + return result; } void CardTableExtension::resize_update_committed_table(int changed_region, diff -r 13152be884e5 -r ea2cf3a72a66 hotspot/src/share/vm/gc_implementation/parallelScavenge/cardTableExtension.hpp --- a/hotspot/src/share/vm/gc_implementation/parallelScavenge/cardTableExtension.hpp Tue Jun 15 18:07:27 2010 -0700 +++ b/hotspot/src/share/vm/gc_implementation/parallelScavenge/cardTableExtension.hpp Thu Jun 24 15:56:12 2010 -0700 @@ -1,5 +1,5 @@ /* - * Copyright (c) 2001, 2008, Oracle and/or its affiliates. All rights reserved. + * Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it @@ -30,7 +30,9 @@ class CardTableExtension : public CardTableModRefBS { private: // Support methods for resizing the card table. - void resize_commit_uncommit(int changed_region, MemRegion new_region); + // resize_commit_uncommit() returns true if the pages were committed or + // uncommitted + bool resize_commit_uncommit(int changed_region, MemRegion new_region); void resize_update_card_table_entries(int changed_region, MemRegion new_region); void resize_update_committed_table(int changed_region, MemRegion new_region); diff -r 13152be884e5 -r ea2cf3a72a66 hotspot/src/share/vm/memory/cardTableModRefBS.cpp --- a/hotspot/src/share/vm/memory/cardTableModRefBS.cpp Tue Jun 15 18:07:27 2010 -0700 +++ b/hotspot/src/share/vm/memory/cardTableModRefBS.cpp Thu Jun 24 15:56:12 2010 -0700 @@ -1,5 +1,5 @@ /* - * Copyright (c) 2000, 2009, Oracle and/or its affiliates. All rights reserved. + * Copyright (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it @@ -284,12 +284,19 @@ committed_unique_to_self(ind, MemRegion(new_end_aligned, cur_committed.end())); if (!uncommit_region.is_empty()) { - if (!os::uncommit_memory((char*)uncommit_region.start(), - uncommit_region.byte_size())) { - assert(false, "Card table contraction failed"); - // The call failed so don't change the end of the - // committed region. This is better than taking the - // VM down. + // It is not safe to uncommit cards if the boundary between + // the generations is moving. A shrink can uncommit cards + // owned by generation A but being used by generation B. + if (!UseAdaptiveGCBoundary) { + if (!os::uncommit_memory((char*)uncommit_region.start(), + uncommit_region.byte_size())) { + assert(false, "Card table contraction failed"); + // The call failed so don't change the end of the + // committed region. This is better than taking the + // VM down. + new_end_aligned = _committed[ind].end(); + } + } else { new_end_aligned = _committed[ind].end(); } } @@ -297,6 +304,19 @@ // In any case, we can reset the end of the current committed entry. _committed[ind].set_end(new_end_aligned); +#ifdef ASSERT + // Check that the last card in the new region is committed according + // to the tables. + bool covered = false; + for (int cr = 0; cr < _cur_covered_regions; cr++) { + if (_committed[cr].contains(new_end - 1)) { + covered = true; + break; + } + } + assert(covered, "Card for end of new region not committed"); +#endif + // The default of 0 is not necessarily clean cards. jbyte* entry; if (old_region.last() < _whole_heap.start()) { @@ -354,6 +374,9 @@ addr_for((jbyte*) _committed[ind].start()), addr_for((jbyte*) _committed[ind].last())); } + // Touch the last card of the covered region to show that it + // is committed (or SEGV). + debug_only(*byte_for(_covered[ind].last());) debug_only(verify_guard();) } diff -r 13152be884e5 -r ea2cf3a72a66 hotspot/src/share/vm/runtime/arguments.cpp --- a/hotspot/src/share/vm/runtime/arguments.cpp Tue Jun 15 18:07:27 2010 -0700 +++ b/hotspot/src/share/vm/runtime/arguments.cpp Thu Jun 24 15:56:12 2010 -0700 @@ -1376,11 +1376,6 @@ } no_shared_spaces(); - // Set the maximum pause time goal to be a reasonable default. - if (FLAG_IS_DEFAULT(MaxGCPauseMillis)) { - FLAG_SET_DEFAULT(MaxGCPauseMillis, 200); - } - if (FLAG_IS_DEFAULT(MarkStackSize)) { FLAG_SET_DEFAULT(MarkStackSize, 128 * TASKQUEUE_SIZE); } diff -r 13152be884e5 -r ea2cf3a72a66 hotspot/src/share/vm/runtime/globals.hpp --- a/hotspot/src/share/vm/runtime/globals.hpp Tue Jun 15 18:07:27 2010 -0700 +++ b/hotspot/src/share/vm/runtime/globals.hpp Thu Jun 24 15:56:12 2010 -0700 @@ -1975,7 +1975,7 @@ "Adaptive size policy maximum GC pause time goal in msec, " \ "or (G1 Only) the max. GC time per MMU time slice") \ \ - product(intx, GCPauseIntervalMillis, 500, \ + product(uintx, GCPauseIntervalMillis, 0, \ "Time slice for MMU specification") \ \ product(uintx, MaxGCMinorPauseMillis, max_uintx, \