/*

 * Copyright (c) 2015, 2016, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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 */

#include "precompiled.hpp"

#include "gc/g1/g1CollectedHeap.inline.hpp"

#include "gc/g1/g1IHOPControl.hpp"

#include "gc/g1/g1Predictions.hpp"

#include "gc/shared/gcTrace.hpp"

#include "logging/log.hpp"

G1IHOPControl::G1IHOPControl(double initial_ihop_percent) :

  _initial_ihop_percent(initial_ihop_percent),

  _target_occupancy(0),

  _last_allocated_bytes(0),

  _last_allocation_time_s(0.0)

{

  assert(_initial_ihop_percent >= 0.0 && _initial_ihop_percent <= 100.0, "Initial IHOP value must be between 0 and 100 but is %.3f", initial_ihop_percent);

}

void G1IHOPControl::update_target_occupancy(size_t new_target_occupancy) {

  log_debug(gc, ihop)("Target occupancy update: old: " SIZE_FORMAT "B, new: " SIZE_FORMAT "B",

                      _target_occupancy, new_target_occupancy);

  _target_occupancy = new_target_occupancy;

}

void G1IHOPControl::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);

  _last_allocation_time_s = allocation_time_s;

  _last_allocated_bytes = allocated_bytes;

}

void G1IHOPControl::print() {

  assert(_target_occupancy > 0, "Target occupancy still not updated yet.");

  size_t cur_conc_mark_start_threshold = get_conc_mark_start_threshold();

  log_debug(gc, ihop)("Basic information (value update), threshold: " SIZE_FORMAT "B (%1.2f), target occupancy: " SIZE_FORMAT "B, current occupancy: " SIZE_FORMAT "B, "

                      "recent allocation size: " SIZE_FORMAT "B, recent allocation duration: %1.2fms, recent old gen allocation rate: %1.2fB/s, recent marking phase length: %1.2fms",

                      cur_conc_mark_start_threshold,

                      cur_conc_mark_start_threshold * 100.0 / _target_occupancy,

                      _target_occupancy,

                      G1CollectedHeap::heap()->used(),

                      _last_allocated_bytes,

                      _last_allocation_time_s * 1000.0,

                      _last_allocation_time_s > 0.0 ? _last_allocated_bytes / _last_allocation_time_s : 0.0,

                      last_marking_length_s() * 1000.0);

}

void G1IHOPControl::send_trace_event(G1NewTracer* tracer) {

  assert(_target_occupancy > 0, "Target occupancy still not updated yet.");

  tracer->report_basic_ihop_statistics(get_conc_mark_start_threshold(),

                                       _target_occupancy,

                                       G1CollectedHeap::heap()->used(),

                                       _last_allocated_bytes,

                                       _last_allocation_time_s,

                                       last_marking_length_s());

}

G1StaticIHOPControl::G1StaticIHOPControl(double ihop_percent) :

  G1IHOPControl(ihop_percent),

  _last_marking_length_s(0.0) {

}

#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++) {

    ctrl->update_allocation_info(alloc_time, alloc_amount, young_size);

    ctrl->update_marking_length(mark_time);

  }

}

void G1StaticIHOPControl::test() {

  size_t const initial_ihop = 45;

  G1StaticIHOPControl ctrl(initial_ihop);

  ctrl.update_target_occupancy(100);

  size_t threshold = ctrl.get_conc_mark_start_threshold();

  assert(threshold == initial_ihop,

         "Expected IHOP threshold of " SIZE_FORMAT " but is " SIZE_FORMAT, initial_ihop, threshold);

  ctrl.update_allocation_info(100.0, 100, 100);

  threshold = ctrl.get_conc_mark_start_threshold();

  assert(threshold == initial_ihop,

         "Expected IHOP threshold of " SIZE_FORMAT " but is " SIZE_FORMAT, initial_ihop, threshold);

  ctrl.update_marking_length(1000.0);

  threshold = ctrl.get_conc_mark_start_threshold();

  assert(threshold == initial_ihop,

         "Expected IHOP threshold of " SIZE_FORMAT " but is " SIZE_FORMAT, initial_ihop, threshold);

  // Whatever we pass, the IHOP value must stay the same.

  test_update(&ctrl, 2, 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);

  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,

                                             G1Predictions const* predictor,

                                             size_t heap_reserve_percent,

                                             size_t heap_waste_percent) :

  G1IHOPControl(ihop_percent),

  _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 {

  guarantee(_target_occupancy > 0, "Target occupancy still not updated yet.");

  // 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 (size_t)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 pred_promotion_size = (size_t)(pred_marking_time * pred_promotion_rate);

    size_t predicted_needed_bytes_during_marking =

      pred_promotion_size +

      // In reality we would need the maximum size of the young gen during

      // marking. This is a conservative estimate.

      _last_unrestrained_young_size;

    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 (size_t)(_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) {

  G1IHOPControl::update_allocation_info(allocation_time_s, allocated_bytes, additional_buffer_size);

  double allocation_rate = (double) allocated_bytes / allocation_time_s;

  _allocation_rate_s.add(allocation_rate);

  _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() {

  G1IHOPControl::print();

  size_t actual_target = actual_target_threshold();

  log_debug(gc, ihop)("Adaptive IHOP information (value update), threshold: " SIZE_FORMAT "B (%1.2f), internal target occupancy: " SIZE_FORMAT "B, "

                      "occupancy: " SIZE_FORMAT "B, additional buffer size: " SIZE_FORMAT "B, predicted old gen allocation rate: %1.2fB/s, "

                      "predicted marking phase length: %1.2fms, prediction active: %s",

                      get_conc_mark_start_threshold(),

                      percent_of(get_conc_mark_start_threshold(), actual_target),

                      actual_target,

                      G1CollectedHeap::heap()->used(),

                      _last_unrestrained_young_size,

                      _predictor->get_new_prediction(&_allocation_rate_s),

                      _predictor->get_new_prediction(&_marking_times_s) * 1000.0,

                      have_enough_data_for_prediction() ? "true" : "false");

}

void G1AdaptiveIHOPControl::send_trace_event(G1NewTracer* tracer) {

  G1IHOPControl::send_trace_event(tracer);

  tracer->report_adaptive_ihop_statistics(get_conc_mark_start_threshold(),

                                          actual_target_threshold(),

                                          G1CollectedHeap::heap()->used(),

                                          _last_unrestrained_young_size,

                                          _predictor->get_new_prediction(&_allocation_rate_s),

                                          _predictor->get_new_prediction(&_marking_times_s),

                                          have_enough_data_for_prediction());

}

#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, &pred, 0, 0);

  ctrl.update_target_occupancy(target_size);

  // 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();

  G1AdaptiveIHOPControl::test();

}

#endif