#include "gc/g1/g1Predictions.hpp"

#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),

  _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);

}