< prev index next >
src/share/vm/gc/g1/g1IHOPControl.cpp
Print this page
rev 9402 : dihop-changes
rev 9403 : imported patch sihop-thomas-review
rev 9404 : imported patch erik-jmasa-review
rev 9405 : imported patch 8136678-implement-adaptive-sizing-algorithm-for-IHOP
rev 9406 : imported patch aihop-thomas-review
rev 9407 : [mq]: erik-jon-review
@@ -98,89 +98,124 @@
assert(threshold == initial_ihop,
"Expected IHOP threshold of " SIZE_FORMAT " but is " SIZE_FORMAT, initial_ihop, threshold);
}
#endif
-G1AdaptiveIHOPControl::G1AdaptiveIHOPControl(double ihop_percent, size_t initial_target_occupancy, G1Predictions const* predictor) :
+G1AdaptiveIHOPControl::G1AdaptiveIHOPControl(double ihop_percent,
+ size_t initial_target_occupancy,
+ G1Predictions const* predictor,
+ size_t heap_reserve_percent,
+ size_t heap_waste_percent) :
G1IHOPControl(ihop_percent, initial_target_occupancy),
_predictor(predictor),
_marking_times_s(10, 0.95),
_allocation_rate_s(10, 0.95),
- _prev_unrestrained_young_size(0),
- _current_threshold(0.0)
+ _last_unrestrained_young_size(0),
+ _current_threshold(0.0),
+ _heap_reserve_percent(heap_reserve_percent),
+ _heap_waste_percent(heap_waste_percent)
{
- recalculate();
+ calculate();
}
-void G1AdaptiveIHOPControl::recalculate() {
+void G1AdaptiveIHOPControl::calculate() {
if (have_enough_data_for_prediction()) {
double pred_marking_time = _predictor->get_new_prediction(&_marking_times_s);
double pred_promotion_rate = _predictor->get_new_prediction(&_allocation_rate_s);
size_t predicted_needed_bytes_during_marking =
(pred_marking_time * pred_promotion_rate +
- _prev_unrestrained_young_size); // In reality we would need the size of the young gen of the first mixed GC. This is a conservative estimate.
- size_t predicted_initiating_threshold = predicted_needed_bytes_during_marking < _target_occupancy ?
- _target_occupancy - predicted_needed_bytes_during_marking :
+ _last_unrestrained_young_size); // In reality we would need the maximum size of the young gen during marking. This is a conservative estimate.
+
+ size_t internal_threshold = actual_target_threshold();
+ size_t predicted_initiating_threshold = predicted_needed_bytes_during_marking < internal_threshold ?
+ internal_threshold - predicted_needed_bytes_during_marking :
0;
_current_threshold = predicted_initiating_threshold;
} else {
// Use the initial value.
_current_threshold = _initial_ihop_percent * _target_occupancy / 100.0;
}
}
+size_t G1AdaptiveIHOPControl::actual_target_threshold() const {
+ // The actual target threshold takes the heap reserve and the expected waste in
+ // free space into account.
+ // _heap_reserve is that part of the total heap capacity that is reserved for
+ // eventual promotion failure.
+ // _heap_waste is the amount of space will never be reclaimed in any
+ // heap, so can not be used for allocation during marking and must always be
+ // considered.
+
+ double safe_total_heap_percentage = MIN2((double)(_heap_reserve_percent + _heap_waste_percent), 100.0);
+
+ return MIN2(
+ G1CollectedHeap::heap()->max_capacity() * (100.0 - safe_total_heap_percentage) / 100.0,
+ _target_occupancy * (100.0 - _heap_waste_percent) / 100.0
+ );
+}
+
bool G1AdaptiveIHOPControl::have_enough_data_for_prediction() const {
return ((size_t)_marking_times_s.num() >= G1AdaptiveIHOPNumInitialSamples) &&
((size_t)_allocation_rate_s.num() >= G1AdaptiveIHOPNumInitialSamples);
}
void G1AdaptiveIHOPControl::set_target_occupancy(size_t target_occupancy) {
_target_occupancy = target_occupancy;
}
size_t G1AdaptiveIHOPControl::get_conc_mark_start_threshold() {
- recalculate();
+ calculate();
return _current_threshold;
}
void G1AdaptiveIHOPControl::update_allocation_info(double allocation_time_s, size_t allocated_bytes, size_t additional_buffer_size) {
assert(allocation_time_s >= 0.0, "Allocation time must be positive but is %.3f", allocation_time_s);
double allocation_rate = (double) allocated_bytes / allocation_time_s;
_allocation_rate_s.add(allocation_rate);
_last_allocation_bytes = allocated_bytes;
- _prev_unrestrained_young_size = additional_buffer_size;
+ _last_unrestrained_young_size = additional_buffer_size;
}
void G1AdaptiveIHOPControl::update_marking_length(double marking_length_s) {
assert(marking_length_s >= 0.0, "Marking length must be larger than zero but is %.3f", marking_length_s);
_marking_times_s.add(marking_length_s);
}
+static double percentage_of(double quantity, double base_quantity) {
+ return base_quantity > 0.0 ? (quantity / base_quantity) * 100.0 : 0.0;
+}
+
void G1AdaptiveIHOPControl::print() {
ergo_verbose6(ErgoIHOP,
"basic information",
ergo_format_reason("value update")
ergo_format_byte_perc("threshold")
ergo_format_byte("target occupancy")
ergo_format_byte("current occupancy")
ergo_format_double("recent old gen allocation rate")
ergo_format_double("recent marking phase length"),
get_conc_mark_start_threshold(),
- _target_occupancy > 0 ? (double) get_conc_mark_start_threshold() / _target_occupancy * 100.0 : 0.0,
+ percentage_of(get_conc_mark_start_threshold(), _target_occupancy),
_target_occupancy,
G1CollectedHeap::heap()->used(),
_allocation_rate_s.last(),
_marking_times_s.last()
);
- ergo_verbose3(ErgoIHOP,
+ size_t actual_target = actual_target_threshold();
+ ergo_verbose6(ErgoIHOP,
"adaptive IHOP information",
ergo_format_reason("value update")
+ ergo_format_byte_perc("threshold")
+ ergo_format_byte("internal target occupancy")
ergo_format_double("predicted old gen allocation rate")
ergo_format_double("predicted marking phase length")
ergo_format_str("prediction active"),
+ get_conc_mark_start_threshold(),
+ percentage_of(get_conc_mark_start_threshold(), actual_target),
+ actual_target,
_predictor->get_new_prediction(&_allocation_rate_s),
_predictor->get_new_prediction(&_marking_times_s),
have_enough_data_for_prediction() ? "true" : "false"
);
}
@@ -193,11 +228,11 @@
// The final IHOP value is always
// target_size - (young_size + alloc_amount/alloc_time * marking_time)
G1Predictions pred(0.95);
- G1AdaptiveIHOPControl ctrl(initial_threshold, target_size, &pred);
+ G1AdaptiveIHOPControl ctrl(initial_threshold, target_size, &pred, 0, 0);
// First "load".
size_t const alloc_time1 = 2;
size_t const alloc_amount1 = 10;
size_t const marking_time1 = 2;
@@ -236,11 +271,11 @@
// Third "load". Very high (impossible) allocation rate.
size_t const alloc_time3 = 1;
size_t const alloc_amount3 = 50;
size_t const marking_time3 = 2;
- size_t const settled_ihop3 = 0; // target_size - (young_size + alloc_amount2/alloc_time2 * marking_time2);
+ size_t const settled_ihop3 = 0;
test_update(&ctrl, alloc_time3, alloc_amount3, young_size, marking_time3);
threshold = ctrl.get_conc_mark_start_threshold();
assert(threshold == settled_ihop3,
< prev index next >