void CSetChooserCache::insert(HeapRegion *hr) {
guarantee(false, "CSetChooserCache::insert(): don't call this any more");
assert(!is_full(), "cache should not be empty");
hr->calc_gc_efficiency();
int empty_index;
if (_occupancy == 0) {
empty_index = _first;
} else {
empty_index = trim_index(_first + _occupancy);
assert(_cache[empty_index] == NULL, "last slot should be empty");
int last_index = trim_index(empty_index - 1);
HeapRegion *last = _cache[last_index];
assert(last != NULL,"as the cache is not empty, last should not be empty");
while (empty_index != _first &&
last->gc_efficiency() < hr->gc_efficiency()) {
_cache[empty_index] = last;
last->set_sort_index(get_sort_index(empty_index));
empty_index = last_index;
last_index = trim_index(last_index - 1);
last = _cache[last_index];
}
}
_cache[empty_index] = hr;
hr->set_sort_index(get_sort_index(empty_index));
++_occupancy;
assert(verify(), "cache should be consistent");
}
void G1MMUTrackerQueue::add_pause(double start, double end, bool gc_thread) {
double longest_allowed = longest_pause_internal(start);
if (longest_allowed < 0.0)
longest_allowed = 0.0;
double duration = end - start;
remove_expired_entries(end);
if (_no_entries == QueueLength) {
// OK, right now when we fill up we bomb out
// there are a few ways of dealing with this "gracefully"
// increase the array size (:-)
// remove the oldest entry (this might allow more GC time for
// the time slice than what's allowed)
// consolidate the two entries with the minimum gap between them
// (this might allow less GC time than what's allowed)
guarantee(NOT_PRODUCT(ScavengeALot ||) G1UseFixedWindowMMUTracker,
"array full, currently we can't recover unless +G1UseFixedWindowMMUTracker");
// In the case where ScavengeALot is true, such overflow is not
// uncommon; in such cases, we can, without much loss of precision
// or performance (we are GC'ing most of the time anyway!),
// simply overwrite the oldest entry in the tracker: this
// is also the behaviour when G1UseFixedWindowMMUTracker is enabled.
_head_index = trim_index(_head_index + 1);
assert(_head_index == _tail_index, "Because we have a full circular buffer");
_tail_index = trim_index(_tail_index + 1);
} else {
bool CSetChooserCache::verify() {
guarantee(false, "CSetChooserCache::verify(): don't call this any more");
int index = _first;
HeapRegion *prev = NULL;
for (int i = 0; i < _occupancy; ++i) {
guarantee(_cache[index] != NULL, "cache entry should not be empty");
HeapRegion *hr = _cache[index];
guarantee(!hr->is_young(), "should not be young!");
if (prev != NULL) {
guarantee(prev->gc_efficiency() >= hr->gc_efficiency(),
"cache should be correctly ordered");
}
guarantee(hr->sort_index() == get_sort_index(index),
"sort index should be correct");
index = trim_index(index + 1);
prev = hr;
}
for (int i = 0; i < (CacheLength - _occupancy); ++i) {
guarantee(_cache[index] == NULL, "cache entry should be empty");
index = trim_index(index + 1);
}
guarantee(index == _first, "we should have reached where we started from");
return true;
}
void G1MMUTrackerQueue::add_pause(double start, double end, bool gc_thread) {
double longest_allowed = longest_pause_internal(start);
if (longest_allowed < 0.0)
longest_allowed = 0.0;
double duration = end - start;
remove_expired_entries(end);
if (_no_entries == QueueLength) {
// OK, we've filled up the queue. There are a few ways
// of dealing with this "gracefully"
// increase the array size (:-)
// remove the oldest entry (this might allow more GC time for
// the time slice than what's allowed) - this is what we
// currently do
// consolidate the two entries with the minimum gap between them
// (this might allow less GC time than what's allowed)
// In the case where ScavengeALot is true, such overflow is not
// uncommon; in such cases, we can, without much loss of precision
// or performance (we are GC'ing most of the time anyway!),
// simply overwrite the oldest entry in the tracker.
_head_index = trim_index(_head_index + 1);
assert(_head_index == _tail_index, "Because we have a full circular buffer");
_tail_index = trim_index(_tail_index + 1);
} else {
_head_index = trim_index(_head_index + 1);
++_no_entries;
}
_array[_head_index] = G1MMUTrackerQueueElem(start, end);
}
double G1MMUTrackerQueue::when_internal(double current_time,
double pause_time) {
// if the pause is over the maximum, just assume that it's the maximum
double adjusted_pause_time =
(pause_time > max_gc_time()) ? max_gc_time() : pause_time;
double earliest_end = current_time + adjusted_pause_time;
double limit = earliest_end - _time_slice;
double gc_time = calculate_gc_time(earliest_end);
double diff = gc_time + adjusted_pause_time - max_gc_time();
if (is_double_leq_0(diff))
return 0.0;
int index = _tail_index;
while ( 1 ) {
G1MMUTrackerQueueElem *elem = &_array[index];
if (elem->end_time() > limit) {
if (elem->start_time() > limit)
diff -= elem->duration();
else
diff -= elem->end_time() - limit;
if (is_double_leq_0(diff))
return elem->end_time() + diff + _time_slice - adjusted_pause_time - current_time;
}
index = trim_index(index+1);
guarantee(index != trim_index(_head_index + 1), "should not go past head");
}
}
void G1MMUTrackerQueue::remove_expired_entries(double current_time) {
double limit = current_time - _time_slice;
while (_no_entries > 0) {
if (is_double_geq(limit, _array[_tail_index].end_time())) {
_tail_index = trim_index(_tail_index + 1);
--_no_entries;
} else
return;
}
guarantee(_no_entries == 0, "should have no entries in the array");
}
double G1MMUTrackerQueue::calculate_gc_time(double current_time) {
double gc_time = 0.0;
double limit = current_time - _time_slice;
for (int i = 0; i < _no_entries; ++i) {
int index = trim_index(_tail_index + i);
G1MMUTrackerQueueElem *elem = &_array[index];
if (elem->end_time() > limit) {
if (elem->start_time() > limit)
gc_time += elem->duration();
else
gc_time += elem->end_time() - limit;
}
}
return gc_time;
}
HeapRegion *CSetChooserCache::remove_first() {
guarantee(false, "CSetChooserCache::remove_first(): "
"don't call this any more");
if (_occupancy > 0) {
assert(_cache[_first] != NULL, "cache should have at least one region");
HeapRegion *ret = _cache[_first];
_cache[_first] = NULL;
ret->set_sort_index(-1);
--_occupancy;
_first = trim_index(_first + 1);
assert(verify(), "cache should be consistent");
return ret;
} else {
return NULL;
}
}
G1MMUTrackerQueue::G1MMUTrackerQueue(double time_slice, double max_gc_time) :
G1MMUTracker(time_slice, max_gc_time),
_head_index(0),
_tail_index(trim_index(_head_index+1)),
_no_entries(0) { }