# HG changeset patch # User jiangli # Date 1362681555 28800 # Node ID 0b8f9c8d26175e3e3bf4521ca8215a5ac7f70ed0 # Parent c71e15057f1d7b2bdfb4ac7de97b4b175e7b4d0e# Parent af5ac43f06e9d3ffc43272bf0f32c1cdb9304c76 Merge diff -r af5ac43f06e9 -r 0b8f9c8d2617 make/bsd/makefiles/gcc.make --- a/make/bsd/makefiles/gcc.make Thu Mar 07 10:46:14 2013 -0500 +++ b/make/bsd/makefiles/gcc.make Thu Mar 07 10:39:15 2013 -0800 @@ -229,6 +229,20 @@ CFLAGS += -DDONT_USE_PRECOMPILED_HEADER endif +ifeq ($(OS_VENDOR), Darwin) + # Setting these parameters makes it an error to link to macosx APIs that are + # newer than the given OS version and makes the linked binaries compatible even + # if built on a newer version of the OS. + # The expected format is X.Y.Z + ifeq ($(MACOSX_VERSION_MIN),) + MACOSX_VERSION_MIN=10.7.0 + endif + # The macro takes the version with no dots, ex: 1070 + CFLAGS += -DMAC_OS_X_VERSION_MAX_ALLOWED=$(subst .,,$(MACOSX_VERSION_MIN)) \ + -mmacosx-version-min=$(MACOSX_VERSION_MIN) + LDFLAGS += -mmacosx-version-min=$(MACOSX_VERSION_MIN) +endif + #------------------------------------------------------------------------ # Linker flags diff -r af5ac43f06e9 -r 0b8f9c8d2617 src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.cpp --- a/src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.cpp Thu Mar 07 10:46:14 2013 -0500 +++ b/src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.cpp Thu Mar 07 10:39:15 2013 -0800 @@ -300,8 +300,7 @@ } } -// Wait until the next synchronous GC, a concurrent full gc request, -// or a timeout, whichever is earlier. +// Wait until any cms_lock event void ConcurrentMarkSweepThread::wait_on_cms_lock(long t_millis) { MutexLockerEx x(CGC_lock, Mutex::_no_safepoint_check_flag); @@ -315,15 +314,100 @@ "Should not be set"); } +// Wait until the next synchronous GC, a concurrent full gc request, +// or a timeout, whichever is earlier. +void ConcurrentMarkSweepThread::wait_on_cms_lock_for_scavenge(long t_millis) { + // Wait time in millis or 0 value representing infinite wait for a scavenge + assert(t_millis >= 0, "Wait time for scavenge should be 0 or positive"); + + GenCollectedHeap* gch = GenCollectedHeap::heap(); + double start_time_secs = os::elapsedTime(); + double end_time_secs = start_time_secs + (t_millis / ((double) MILLIUNITS)); + + // Total collections count before waiting loop + unsigned int before_count; + { + MutexLockerEx hl(Heap_lock, Mutex::_no_safepoint_check_flag); + before_count = gch->total_collections(); + } + + unsigned int loop_count = 0; + + while(!_should_terminate) { + double now_time = os::elapsedTime(); + long wait_time_millis; + + if(t_millis != 0) { + // New wait limit + wait_time_millis = (long) ((end_time_secs - now_time) * MILLIUNITS); + if(wait_time_millis <= 0) { + // Wait time is over + break; + } + } else { + // No wait limit, wait if necessary forever + wait_time_millis = 0; + } + + // Wait until the next event or the remaining timeout + { + MutexLockerEx x(CGC_lock, Mutex::_no_safepoint_check_flag); + + if (_should_terminate || _collector->_full_gc_requested) { + return; + } + set_CMS_flag(CMS_cms_wants_token); // to provoke notifies + assert(t_millis == 0 || wait_time_millis > 0, "Sanity"); + CGC_lock->wait(Mutex::_no_safepoint_check_flag, wait_time_millis); + clear_CMS_flag(CMS_cms_wants_token); + assert(!CMS_flag_is_set(CMS_cms_has_token | CMS_cms_wants_token), + "Should not be set"); + } + + // Extra wait time check before entering the heap lock to get the collection count + if(t_millis != 0 && os::elapsedTime() >= end_time_secs) { + // Wait time is over + break; + } + + // Total collections count after the event + unsigned int after_count; + { + MutexLockerEx hl(Heap_lock, Mutex::_no_safepoint_check_flag); + after_count = gch->total_collections(); + } + + if(before_count != after_count) { + // There was a collection - success + break; + } + + // Too many loops warning + if(++loop_count == 0) { + warning("wait_on_cms_lock_for_scavenge() has looped %u times", loop_count - 1); + } + } +} + void ConcurrentMarkSweepThread::sleepBeforeNextCycle() { while (!_should_terminate) { if (CMSIncrementalMode) { icms_wait(); + if(CMSWaitDuration >= 0) { + // Wait until the next synchronous GC, a concurrent full gc + // request or a timeout, whichever is earlier. + wait_on_cms_lock_for_scavenge(CMSWaitDuration); + } return; } else { - // Wait until the next synchronous GC, a concurrent full gc - // request or a timeout, whichever is earlier. - wait_on_cms_lock(CMSWaitDuration); + if(CMSWaitDuration >= 0) { + // Wait until the next synchronous GC, a concurrent full gc + // request or a timeout, whichever is earlier. + wait_on_cms_lock_for_scavenge(CMSWaitDuration); + } else { + // Wait until any cms_lock event or check interval not to call shouldConcurrentCollect permanently + wait_on_cms_lock(CMSCheckInterval); + } } // Check if we should start a CMS collection cycle if (_collector->shouldConcurrentCollect()) { diff -r af5ac43f06e9 -r 0b8f9c8d2617 src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp --- a/src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp Thu Mar 07 10:46:14 2013 -0500 +++ b/src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp Thu Mar 07 10:39:15 2013 -0800 @@ -130,6 +130,12 @@ // A concurrent full gc request terminates the wait. void wait_on_cms_lock(long t_millis); + // Wait on CMS lock until the next synchronous GC + // or given timeout, whichever is earlier. A timeout value + // of 0 indicates that there is no upper bound on the wait time. + // A concurrent full gc request terminates the wait. + void wait_on_cms_lock_for_scavenge(long t_millis); + // The CMS thread will yield during the work portion of its cycle // only when requested to. Both synchronous and asychronous requests // are provided: diff -r af5ac43f06e9 -r 0b8f9c8d2617 src/share/vm/gc_implementation/g1/collectionSetChooser.cpp --- a/src/share/vm/gc_implementation/g1/collectionSetChooser.cpp Thu Mar 07 10:46:14 2013 -0500 +++ b/src/share/vm/gc_implementation/g1/collectionSetChooser.cpp Thu Mar 07 10:39:15 2013 -0800 @@ -146,43 +146,6 @@ verify(); } -uint CollectionSetChooser::calc_min_old_cset_length() { - // The min old CSet region bound is based on the maximum desired - // number of mixed GCs after a cycle. I.e., even if some old regions - // look expensive, we should add them to the CSet anyway to make - // sure we go through the available old regions in no more than the - // maximum desired number of mixed GCs. - // - // The calculation is based on the number of marked regions we added - // to the CSet chooser in the first place, not how many remain, so - // that the result is the same during all mixed GCs that follow a cycle. - - const size_t region_num = (size_t) _length; - const size_t gc_num = (size_t) G1MixedGCCountTarget; - size_t result = region_num / gc_num; - // emulate ceiling - if (result * gc_num < region_num) { - result += 1; - } - return (uint) result; -} - -uint CollectionSetChooser::calc_max_old_cset_length() { - // The max old CSet region bound is based on the threshold expressed - // as a percentage of the heap size. I.e., it should bound the - // number of old regions added to the CSet irrespective of how many - // of them are available. - - G1CollectedHeap* g1h = G1CollectedHeap::heap(); - const size_t region_num = g1h->n_regions(); - const size_t perc = (size_t) G1OldCSetRegionThresholdPercent; - size_t result = region_num * perc / 100; - // emulate ceiling - if (100 * result < region_num * perc) { - result += 1; - } - return (uint) result; -} void CollectionSetChooser::add_region(HeapRegion* hr) { assert(!hr->isHumongous(), diff -r af5ac43f06e9 -r 0b8f9c8d2617 src/share/vm/gc_implementation/g1/collectionSetChooser.hpp --- a/src/share/vm/gc_implementation/g1/collectionSetChooser.hpp Thu Mar 07 10:46:14 2013 -0500 +++ b/src/share/vm/gc_implementation/g1/collectionSetChooser.hpp Thu Mar 07 10:39:15 2013 -0800 @@ -51,6 +51,8 @@ uint _curr_index; // The number of candidate old regions added to the CSet chooser. + // Note: this is not updated when removing a region using + // remove_and_move_to_next() below. uint _length; // Keeps track of the start of the next array chunk to be claimed by @@ -111,13 +113,8 @@ hr->live_bytes() < _region_live_threshold_bytes; } - // Calculate the minimum number of old regions we'll add to the CSet - // during a mixed GC. - uint calc_min_old_cset_length(); - - // Calculate the maximum number of old regions we'll add to the CSet - // during a mixed GC. - uint calc_max_old_cset_length(); + // Returns the number candidate old regions added + uint length() { return _length; } // Serial version. void add_region(HeapRegion *hr); diff -r af5ac43f06e9 -r 0b8f9c8d2617 src/share/vm/gc_implementation/g1/g1CollectorPolicy.cpp --- a/src/share/vm/gc_implementation/g1/g1CollectorPolicy.cpp Thu Mar 07 10:46:14 2013 -0500 +++ b/src/share/vm/gc_implementation/g1/g1CollectorPolicy.cpp Thu Mar 07 10:39:15 2013 -0800 @@ -1806,6 +1806,14 @@ } #endif // !PRODUCT +double G1CollectorPolicy::reclaimable_bytes_perc(size_t reclaimable_bytes) { + // Returns the given amount of reclaimable bytes (that represents + // the amount of reclaimable space still to be collected) as a + // percentage of the current heap capacity. + size_t capacity_bytes = _g1->capacity(); + return (double) reclaimable_bytes * 100.0 / (double) capacity_bytes; +} + bool G1CollectorPolicy::next_gc_should_be_mixed(const char* true_action_str, const char* false_action_str) { CollectionSetChooser* cset_chooser = _collectionSetChooser; @@ -1815,19 +1823,21 @@ ergo_format_reason("candidate old regions not available")); return false; } + + // Is the amount of uncollected reclaimable space above G1HeapWastePercent? size_t reclaimable_bytes = cset_chooser->remaining_reclaimable_bytes(); - size_t capacity_bytes = _g1->capacity(); - double perc = (double) reclaimable_bytes * 100.0 / (double) capacity_bytes; + double reclaimable_perc = reclaimable_bytes_perc(reclaimable_bytes); double threshold = (double) G1HeapWastePercent; - if (perc < threshold) { + if (reclaimable_perc <= threshold) { ergo_verbose4(ErgoMixedGCs, false_action_str, - ergo_format_reason("reclaimable percentage lower than threshold") + ergo_format_reason("reclaimable percentage not over threshold") ergo_format_region("candidate old regions") ergo_format_byte_perc("reclaimable") ergo_format_perc("threshold"), cset_chooser->remaining_regions(), - reclaimable_bytes, perc, threshold); + reclaimable_bytes, + reclaimable_perc, threshold); return false; } @@ -1838,10 +1848,50 @@ ergo_format_byte_perc("reclaimable") ergo_format_perc("threshold"), cset_chooser->remaining_regions(), - reclaimable_bytes, perc, threshold); + reclaimable_bytes, + reclaimable_perc, threshold); return true; } +uint G1CollectorPolicy::calc_min_old_cset_length() { + // The min old CSet region bound is based on the maximum desired + // number of mixed GCs after a cycle. I.e., even if some old regions + // look expensive, we should add them to the CSet anyway to make + // sure we go through the available old regions in no more than the + // maximum desired number of mixed GCs. + // + // The calculation is based on the number of marked regions we added + // to the CSet chooser in the first place, not how many remain, so + // that the result is the same during all mixed GCs that follow a cycle. + + const size_t region_num = (size_t) _collectionSetChooser->length(); + const size_t gc_num = (size_t) MAX2(G1MixedGCCountTarget, (uintx) 1); + size_t result = region_num / gc_num; + // emulate ceiling + if (result * gc_num < region_num) { + result += 1; + } + return (uint) result; +} + +uint G1CollectorPolicy::calc_max_old_cset_length() { + // The max old CSet region bound is based on the threshold expressed + // as a percentage of the heap size. I.e., it should bound the + // number of old regions added to the CSet irrespective of how many + // of them are available. + + G1CollectedHeap* g1h = G1CollectedHeap::heap(); + const size_t region_num = g1h->n_regions(); + const size_t perc = (size_t) G1OldCSetRegionThresholdPercent; + size_t result = region_num * perc / 100; + // emulate ceiling + if (100 * result < region_num * perc) { + result += 1; + } + return (uint) result; +} + + void G1CollectorPolicy::finalize_cset(double target_pause_time_ms) { double young_start_time_sec = os::elapsedTime(); @@ -1855,7 +1905,7 @@ double base_time_ms = predict_base_elapsed_time_ms(_pending_cards); double predicted_pause_time_ms = base_time_ms; - double time_remaining_ms = target_pause_time_ms - base_time_ms; + double time_remaining_ms = MAX2(target_pause_time_ms - base_time_ms, 0.0); ergo_verbose4(ErgoCSetConstruction | ErgoHigh, "start choosing CSet", @@ -1893,7 +1943,7 @@ _collection_set = _inc_cset_head; _collection_set_bytes_used_before = _inc_cset_bytes_used_before; - time_remaining_ms -= _inc_cset_predicted_elapsed_time_ms; + time_remaining_ms = MAX2(time_remaining_ms - _inc_cset_predicted_elapsed_time_ms, 0.0); predicted_pause_time_ms += _inc_cset_predicted_elapsed_time_ms; ergo_verbose3(ErgoCSetConstruction | ErgoHigh, @@ -1917,8 +1967,8 @@ if (!gcs_are_young()) { CollectionSetChooser* cset_chooser = _collectionSetChooser; cset_chooser->verify(); - const uint min_old_cset_length = cset_chooser->calc_min_old_cset_length(); - const uint max_old_cset_length = cset_chooser->calc_max_old_cset_length(); + const uint min_old_cset_length = calc_min_old_cset_length(); + const uint max_old_cset_length = calc_max_old_cset_length(); uint expensive_region_num = 0; bool check_time_remaining = adaptive_young_list_length(); @@ -1936,6 +1986,30 @@ break; } + + // Stop adding regions if the remaining reclaimable space is + // not above G1HeapWastePercent. + size_t reclaimable_bytes = cset_chooser->remaining_reclaimable_bytes(); + double reclaimable_perc = reclaimable_bytes_perc(reclaimable_bytes); + double threshold = (double) G1HeapWastePercent; + if (reclaimable_perc <= threshold) { + // We've added enough old regions that the amount of uncollected + // reclaimable space is at or below the waste threshold. Stop + // adding old regions to the CSet. + ergo_verbose5(ErgoCSetConstruction, + "finish adding old regions to CSet", + ergo_format_reason("reclaimable percentage not over threshold") + ergo_format_region("old") + ergo_format_region("max") + ergo_format_byte_perc("reclaimable") + ergo_format_perc("threshold"), + old_cset_region_length(), + max_old_cset_length, + reclaimable_bytes, + reclaimable_perc, threshold); + break; + } + double predicted_time_ms = predict_region_elapsed_time_ms(hr, gcs_are_young()); if (check_time_remaining) { if (predicted_time_ms > time_remaining_ms) { @@ -1975,7 +2049,7 @@ } // We will add this region to the CSet. - time_remaining_ms -= predicted_time_ms; + time_remaining_ms = MAX2(time_remaining_ms - predicted_time_ms, 0.0); predicted_pause_time_ms += predicted_time_ms; cset_chooser->remove_and_move_to_next(hr); _g1->old_set_remove(hr); diff -r af5ac43f06e9 -r 0b8f9c8d2617 src/share/vm/gc_implementation/g1/g1CollectorPolicy.hpp --- a/src/share/vm/gc_implementation/g1/g1CollectorPolicy.hpp Thu Mar 07 10:46:14 2013 -0500 +++ b/src/share/vm/gc_implementation/g1/g1CollectorPolicy.hpp Thu Mar 07 10:39:15 2013 -0800 @@ -619,6 +619,18 @@ bool predict_will_fit(uint young_length, double base_time_ms, uint base_free_regions, double target_pause_time_ms); + // Calculate the minimum number of old regions we'll add to the CSet + // during a mixed GC. + uint calc_min_old_cset_length(); + + // Calculate the maximum number of old regions we'll add to the CSet + // during a mixed GC. + uint calc_max_old_cset_length(); + + // Returns the given amount of uncollected reclaimable space + // as a percentage of the current heap capacity. + double reclaimable_bytes_perc(size_t reclaimable_bytes); + public: G1CollectorPolicy(); diff -r af5ac43f06e9 -r 0b8f9c8d2617 src/share/vm/memory/metaspaceCounters.cpp --- a/src/share/vm/memory/metaspaceCounters.cpp Thu Mar 07 10:46:14 2013 -0500 +++ b/src/share/vm/memory/metaspaceCounters.cpp Thu Mar 07 10:39:15 2013 -0800 @@ -25,12 +25,14 @@ #include "precompiled.hpp" #include "memory/metaspaceCounters.hpp" #include "memory/resourceArea.hpp" - -#define METASPACE_NAME "perm" +#include "utilities/exceptions.hpp" MetaspaceCounters* MetaspaceCounters::_metaspace_counters = NULL; -MetaspaceCounters::MetaspaceCounters() { +MetaspaceCounters::MetaspaceCounters() : + _capacity(NULL), + _used(NULL), + _max_capacity(NULL) { if (UsePerfData) { size_t min_capacity = MetaspaceAux::min_chunk_size(); size_t max_capacity = MetaspaceAux::reserved_in_bytes(); @@ -41,6 +43,25 @@ } } +static PerfVariable* create_ms_variable(const char *ns, + const char *name, + size_t value, + TRAPS) { + const char *path = PerfDataManager::counter_name(ns, name); + PerfVariable *result = + PerfDataManager::create_variable(SUN_GC, path, PerfData::U_Bytes, value, + CHECK_NULL); + return result; +} + +static void create_ms_constant(const char *ns, + const char *name, + size_t value, + TRAPS) { + const char *path = PerfDataManager::counter_name(ns, name); + PerfDataManager::create_constant(SUN_GC, path, PerfData::U_Bytes, value, CHECK); +} + void MetaspaceCounters::initialize(size_t min_capacity, size_t max_capacity, size_t curr_capacity, @@ -50,93 +71,32 @@ EXCEPTION_MARK; ResourceMark rm; - // Create a name that will be recognized by jstat tools as - // the perm gen. Change this to a Metaspace name when the - // tools are fixed. - // name to recognize "sun.gc.generation.2.*" - - const char* name = METASPACE_NAME; - const int ordinal = 2; - const int spaces = 1; - - const char* cns = PerfDataManager::name_space("generation", ordinal); - - _name_space = NEW_C_HEAP_ARRAY(char, strlen(cns)+1, mtClass); - strcpy(_name_space, cns); - - const char* cname = PerfDataManager::counter_name(_name_space, "name"); - PerfDataManager::create_string_constant(SUN_GC, cname, name, CHECK); - - // End of perm gen like name creation - - cname = PerfDataManager::counter_name(_name_space, "spaces"); - PerfDataManager::create_constant(SUN_GC, cname, PerfData::U_None, - spaces, CHECK); - - cname = PerfDataManager::counter_name(_name_space, "minCapacity"); - PerfDataManager::create_constant(SUN_GC, cname, PerfData::U_Bytes, - min_capacity, CHECK); - - cname = PerfDataManager::counter_name(_name_space, "maxCapacity"); - PerfDataManager::create_constant(SUN_GC, cname, PerfData::U_Bytes, - max_capacity, CHECK); + const char *ms = "metaspace"; - cname = PerfDataManager::counter_name(_name_space, "capacity"); - _current_size = - PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, - curr_capacity, CHECK); - - // SpaceCounter like counters - // name to recognize "sun.gc.generation.2.space.0.*" - { - const int space_ordinal = 0; - const char* cns = PerfDataManager::name_space(_name_space, "space", - space_ordinal); - - char* space_name_space = NEW_C_HEAP_ARRAY(char, strlen(cns)+1, mtClass); - strcpy(space_name_space, cns); - - const char* cname = PerfDataManager::counter_name(space_name_space, "name"); - PerfDataManager::create_string_constant(SUN_GC, cname, name, CHECK); - - cname = PerfDataManager::counter_name(space_name_space, "maxCapacity"); - _max_capacity = PerfDataManager::create_variable(SUN_GC, cname, - PerfData::U_Bytes, - (jlong)max_capacity, CHECK); - - cname = PerfDataManager::counter_name(space_name_space, "capacity"); - _capacity = PerfDataManager::create_variable(SUN_GC, cname, - PerfData::U_Bytes, - curr_capacity, CHECK); - - cname = PerfDataManager::counter_name(space_name_space, "used"); - _used = PerfDataManager::create_variable(SUN_GC, - cname, - PerfData::U_Bytes, - used, - CHECK); - - cname = PerfDataManager::counter_name(space_name_space, "initCapacity"); - PerfDataManager::create_constant(SUN_GC, cname, PerfData::U_Bytes, - min_capacity, CHECK); - } + create_ms_constant(ms, "minCapacity", min_capacity, CHECK); + _max_capacity = create_ms_variable(ms, "maxCapacity", max_capacity, CHECK); + _capacity = create_ms_variable(ms, "capacity", curr_capacity, CHECK); + _used = create_ms_variable(ms, "used", used, CHECK); } } void MetaspaceCounters::update_capacity() { assert(UsePerfData, "Should not be called unless being used"); + assert(_capacity != NULL, "Should be initialized"); size_t capacity_in_bytes = MetaspaceAux::capacity_in_bytes(); _capacity->set_value(capacity_in_bytes); } void MetaspaceCounters::update_used() { assert(UsePerfData, "Should not be called unless being used"); + assert(_used != NULL, "Should be initialized"); size_t used_in_bytes = MetaspaceAux::used_in_bytes(); _used->set_value(used_in_bytes); } void MetaspaceCounters::update_max_capacity() { assert(UsePerfData, "Should not be called unless being used"); + assert(_max_capacity != NULL, "Should be initialized"); size_t reserved_in_bytes = MetaspaceAux::reserved_in_bytes(); _max_capacity->set_value(reserved_in_bytes); } @@ -146,18 +106,19 @@ update_used(); update_capacity(); update_max_capacity(); - _current_size->set_value(MetaspaceAux::reserved_in_bytes()); } } void MetaspaceCounters::initialize_performance_counters() { if (UsePerfData) { + assert(_metaspace_counters == NULL, "Should only be initialized once"); _metaspace_counters = new MetaspaceCounters(); } } void MetaspaceCounters::update_performance_counters() { if (UsePerfData) { + assert(_metaspace_counters != NULL, "Should be initialized"); _metaspace_counters->update_all(); } } diff -r af5ac43f06e9 -r 0b8f9c8d2617 src/share/vm/memory/metaspaceCounters.hpp --- a/src/share/vm/memory/metaspaceCounters.hpp Thu Mar 07 10:46:14 2013 -0500 +++ b/src/share/vm/memory/metaspaceCounters.hpp Thu Mar 07 10:39:15 2013 -0800 @@ -29,11 +29,9 @@ class MetaspaceCounters: public CHeapObj { friend class VMStructs; - PerfVariable* _current_size; PerfVariable* _capacity; PerfVariable* _used; PerfVariable* _max_capacity; - char* _name_space; static MetaspaceCounters* _metaspace_counters; void initialize(size_t min_capacity, size_t max_capacity, diff -r af5ac43f06e9 -r 0b8f9c8d2617 src/share/vm/runtime/globals.hpp --- a/src/share/vm/runtime/globals.hpp Thu Mar 07 10:46:14 2013 -0500 +++ b/src/share/vm/runtime/globals.hpp Thu Mar 07 10:39:15 2013 -0800 @@ -1751,6 +1751,10 @@ manageable(intx, CMSWaitDuration, 2000, \ "Time in milliseconds that CMS thread waits for young GC") \ \ + develop(uintx, CMSCheckInterval, 1000, \ + "Interval in milliseconds that CMS thread checks if it " \ + "should start a collection cycle") \ + \ product(bool, CMSYield, true, \ "Yield between steps of concurrent mark & sweep") \ \