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src/share/vm/gc/g1/g1IHOPControl.cpp
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rev 9431 : dihop-changes
rev 9432 : imported patch sihop-thomas-review
rev 9433 : imported patch erik-jmasa-review
rev 9434 : imported patch fix-evac-failure-needs-stats
rev 9435 : imported patch mikael-erik-review
rev 9436 : [mq]: 8136678-implement-adaptive-sizing-algorithm-for-IHOP
rev 9437 : imported patch aihop-thomas-review
rev 9438 : imported patch erik-jon-review2
rev 9439 : imported patch further-jon-reviews
rev 9440 : [mq]: mikael-review
@@ -24,10 +24,11 @@
#include "precompiled.hpp"
#include "gc/g1/g1CollectedHeap.inline.hpp"
#include "gc/g1/g1ErgoVerbose.hpp"
#include "gc/g1/g1IHOPControl.hpp"
+#include "gc/g1/g1Predictions.hpp"
G1IHOPControl::G1IHOPControl(double initial_ihop_percent, size_t target_occupancy) :
_initial_ihop_percent(initial_ihop_percent),
_target_occupancy(target_occupancy),
_last_allocated_bytes(0),
@@ -103,10 +104,186 @@
test_update(&ctrl, 12, 10, 10, 3);
threshold = ctrl.get_conc_mark_start_threshold();
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,
+ size_t heap_reserve_percent,
+ size_t heap_waste_percent) :
+ G1IHOPControl(ihop_percent, initial_target_occupancy),
+ _predictor(predictor),
+ // A sigma of 0.95 favors more recent samples.
+ _marking_times_s(10, 0.95),
+ _allocation_rate_s(10, 0.95),
+ _last_unrestrained_young_size(0),
+ _heap_reserve_percent(heap_reserve_percent),
+ _heap_waste_percent(heap_waste_percent)
+{
+}
+
+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);
+}
+
+size_t G1AdaptiveIHOPControl::get_conc_mark_start_threshold() {
+ 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 +
+ _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;
+ return predicted_initiating_threshold;
+ } else {
+ // Use the initial value.
+ return _initial_ihop_percent * _target_occupancy / 100.0;
+ }
+}
+
+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;
+ _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);
+}
+
+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(),
+ percent_of(get_conc_mark_start_threshold(), _target_occupancy),
+ _target_occupancy,
+ G1CollectedHeap::heap()->used(),
+ _allocation_rate_s.last(),
+ _marking_times_s.last()
+ );
+ 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(),
+ percent_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"
+ );
+}
+
+#ifndef PRODUCT
+void G1AdaptiveIHOPControl::test() {
+ size_t const initial_threshold = 45;
+ size_t const young_size = 10;
+ size_t const target_size = 100;
+
+ // 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, 0, 0);
+
+ // First "load".
+ size_t const alloc_time1 = 2;
+ size_t const alloc_amount1 = 10;
+ size_t const marking_time1 = 2;
+ size_t const settled_ihop1 = target_size - (young_size + alloc_amount1/alloc_time1 * marking_time1);
+
+ size_t threshold;
+ threshold = ctrl.get_conc_mark_start_threshold();
+ assert(threshold == initial_threshold,
+ "Expected IHOP threshold of " SIZE_FORMAT " but is " SIZE_FORMAT, initial_threshold, threshold);
+ for (size_t i = 0; i < G1AdaptiveIHOPNumInitialSamples - 1; i++) {
+ ctrl.update_allocation_info(alloc_time1, alloc_amount1, young_size);
+ ctrl.update_marking_length(marking_time1);
+ // Not enough data yet.
+ threshold = ctrl.get_conc_mark_start_threshold();
+ assert(threshold == initial_threshold,
+ "Expected IHOP threshold of " SIZE_FORMAT " but is " SIZE_FORMAT, initial_threshold, threshold);
+ }
+
+ test_update(&ctrl, alloc_time1, alloc_amount1, young_size, marking_time1);
+
+ threshold = ctrl.get_conc_mark_start_threshold();
+ assert(threshold == settled_ihop1,
+ "Expected IHOP threshold to settle at " SIZE_FORMAT " but is " SIZE_FORMAT, settled_ihop1, threshold);
+
+ // Second "load". A bit higher allocation rate.
+ size_t const alloc_time2 = 2;
+ size_t const alloc_amount2 = 30;
+ size_t const marking_time2 = 2;
+ size_t const settled_ihop2 = target_size - (young_size + alloc_amount2/alloc_time2 * marking_time2);
+
+ test_update(&ctrl, alloc_time2, alloc_amount2, young_size, marking_time2);
+
+ threshold = ctrl.get_conc_mark_start_threshold();
+ assert(threshold < settled_ihop1,
+ "Expected IHOP threshold to settle at a value lower than " SIZE_FORMAT " but is " SIZE_FORMAT, settled_ihop1, threshold);
+
+ // 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;
+
+ test_update(&ctrl, alloc_time3, alloc_amount3, young_size, marking_time3);
+ threshold = ctrl.get_conc_mark_start_threshold();
+
+ assert(threshold == settled_ihop3,
+ "Expected IHOP threshold to settle at " SIZE_FORMAT " but is " SIZE_FORMAT, settled_ihop3, threshold);
+
+ // And back to some arbitrary value.
+ test_update(&ctrl, alloc_time2, alloc_amount2, young_size, marking_time2);
+
+ threshold = ctrl.get_conc_mark_start_threshold();
+ assert(threshold > settled_ihop3,
+ "Expected IHOP threshold to settle at value larger than " SIZE_FORMAT " but is " SIZE_FORMAT, settled_ihop3, threshold);
+}
void IHOP_test() {
G1StaticIHOPControl::test();
}
#endif
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