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src/share/vm/gc/g1/g1IHOPControl.cpp
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rev 9313 : [mq]: aihop-thomas-review
@@ -48,17 +48,17 @@
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_ms("recent marking phase length"),
+ ergo_format_double("recent marking phase length"),
get_conc_mark_start_threshold(),
(double) get_conc_mark_start_threshold() / _target_occupancy * 100.0,
_target_occupancy,
G1CollectedHeap::heap()->used(),
_last_allocation_time_s > 0.0 ? _last_allocated_bytes / _last_allocation_time_s : 0.0,
- _last_marking_length_s * 1000.0);
+ _last_marking_length_s);
}
#ifndef PRODUCT
static void test_update(G1IHOPControl* ctrl, double alloc_time, size_t alloc_amount, size_t young_size, double mark_time) {
for (int i = 0; i < 100; i++) {
@@ -98,10 +98,167 @@
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) :
+ 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)
+{
+ recalculate();
+}
+
+void G1AdaptiveIHOPControl::recalculate() {
+ 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 :
+ 0;
+ _current_threshold = predicted_initiating_threshold;
+ } else {
+ // Use the initial value.
+ _current_threshold = _ihop_percent * _target_occupancy / 100.0;
+ }
+}
+
+bool G1AdaptiveIHOPControl::have_enough_data_for_prediction() const {
+ return (_marking_times_s.num() > 2) && (_allocation_rate_s.num() > 2);
+}
+
+void G1AdaptiveIHOPControl::set_target_occupancy(size_t target_occupancy) {
+ _target_occupancy = target_occupancy;
+}
+
+size_t G1AdaptiveIHOPControl::get_conc_mark_start_threshold() {
+ recalculate();
+ 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;
+}
+
+void G1AdaptiveIHOPControl::update_time_to_mixed(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(),
+ _target_occupancy > 0 ? (double) get_conc_mark_start_threshold() / _target_occupancy * 100.0 : 0.0,
+ _target_occupancy,
+ G1CollectedHeap::heap()->used(),
+ _allocation_rate_s.last(),
+ _marking_times_s.last()
+ );
+ ergo_verbose3(ErgoIHOP,
+ "adaptive IHOP information",
+ ergo_format_reason("value update")
+ ergo_format_double("predicted old gen allocation rate")
+ ergo_format_double("predicted marking phase length")
+ ergo_format_str("prediction active"),
+ _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);
+
+ // 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);
+ ctrl.update_allocation_info(alloc_time1, alloc_amount1, young_size);
+ ctrl.update_time_to_mixed(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);
+ // Not enough data yet.
+ ctrl.update_allocation_info(alloc_time1, alloc_amount1, young_size);
+ ctrl.update_time_to_mixed(marking_time1);
+ 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; // target_size - (young_size + alloc_amount2/alloc_time2 * marking_time2);
+
+ 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();
+ G1AdaptiveIHOPControl::test();
}
#endif
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