/*

 * Copyright (c) 2016, 2018, 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

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 *

 */

#include "precompiled.hpp"

#include "gc/g1/g1Analytics.hpp"

#include "gc/g1/g1Predictions.hpp"

#include "runtime/os.hpp"

#include "utilities/debug.hpp"

#include "utilities/numberSeq.hpp"

// Different defaults for different number of GC threads

// They were chosen by running GCOld and SPECjbb on debris with different

//   numbers of GC threads and choosing them based on the results

// all the same

static double rs_length_diff_defaults[] = {

  0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0

};

static double cost_per_log_buffer_entry_ms_defaults[] = {

  0.01, 0.005, 0.005, 0.003, 0.003, 0.002, 0.002, 0.0015

};

// all the same

static double young_cards_per_entry_ratio_defaults[] = {

  1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0

};

static double young_only_cost_per_remset_card_ms_defaults[] = {

  0.015, 0.01, 0.01, 0.008, 0.008, 0.0055, 0.0055, 0.005

};

static double cost_per_byte_ms_defaults[] = {

  0.00006, 0.00003, 0.00003, 0.000015, 0.000015, 0.00001, 0.00001, 0.000009

};

// these should be pretty consistent

static double constant_other_time_ms_defaults[] = {

  5.0, 5.0, 5.0, 5.0, 5.0, 5.0, 5.0, 5.0

};

static double young_other_cost_per_region_ms_defaults[] = {

  0.3, 0.2, 0.2, 0.15, 0.15, 0.12, 0.12, 0.1

};

static double non_young_other_cost_per_region_ms_defaults[] = {

  1.0, 0.7, 0.7, 0.5, 0.5, 0.42, 0.42, 0.30

};

G1Analytics::G1Analytics(const G1Predictions* predictor) :

    _predictor(predictor),

    _recent_gc_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),

    _concurrent_mark_remark_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),

    _concurrent_mark_cleanup_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),

    _alloc_rate_ms_seq(new TruncatedSeq(TruncatedSeqLength)),

    _prev_collection_pause_end_ms(0.0),

    _rs_length_diff_seq(new TruncatedSeq(TruncatedSeqLength)),

    _cost_per_log_buffer_entry_ms_seq(new TruncatedSeq(TruncatedSeqLength)),

    _cost_scan_hcc_seq(new TruncatedSeq(TruncatedSeqLength)),

    _young_cards_per_entry_ratio_seq(new TruncatedSeq(TruncatedSeqLength)),

    _mixed_cards_per_entry_ratio_seq(new TruncatedSeq(TruncatedSeqLength)),

    _young_only_cost_per_remset_card_ms_seq(new TruncatedSeq(TruncatedSeqLength)),

    _mixed_cost_per_remset_card_ms_seq(new TruncatedSeq(TruncatedSeqLength)),

    _cost_per_byte_ms_seq(new TruncatedSeq(TruncatedSeqLength)),

    _constant_other_time_ms_seq(new TruncatedSeq(TruncatedSeqLength)),

    _young_other_cost_per_region_ms_seq(new TruncatedSeq(TruncatedSeqLength)),

    _non_young_other_cost_per_region_ms_seq(new TruncatedSeq(TruncatedSeqLength)),

    _pending_cards_seq(new TruncatedSeq(TruncatedSeqLength)),

    _rs_length_seq(new TruncatedSeq(TruncatedSeqLength)),

    _cost_per_byte_ms_during_cm_seq(new TruncatedSeq(TruncatedSeqLength)),

    _recent_prev_end_times_for_all_gcs_sec(new TruncatedSeq(NumPrevPausesForHeuristics)),

    _recent_avg_pause_time_ratio(0.0),

    _last_pause_time_ratio(0.0) {

  // Seed sequences with initial values.

  _recent_prev_end_times_for_all_gcs_sec->add(os::elapsedTime());

  _prev_collection_pause_end_ms = os::elapsedTime() * 1000.0;

  int index = MIN2(ParallelGCThreads - 1, 7u);

  _rs_length_diff_seq->add(rs_length_diff_defaults[index]);

  _cost_per_log_buffer_entry_ms_seq->add(cost_per_log_buffer_entry_ms_defaults[index]);

  _cost_scan_hcc_seq->add(0.0);

  _young_cards_per_entry_ratio_seq->add(young_cards_per_entry_ratio_defaults[index]);

  _young_only_cost_per_remset_card_ms_seq->add(young_only_cost_per_remset_card_ms_defaults[index]);

  _cost_per_byte_ms_seq->add(cost_per_byte_ms_defaults[index]);

  _constant_other_time_ms_seq->add(constant_other_time_ms_defaults[index]);

  _young_other_cost_per_region_ms_seq->add(young_other_cost_per_region_ms_defaults[index]);

  _non_young_other_cost_per_region_ms_seq->add(non_young_other_cost_per_region_ms_defaults[index]);

  // start conservatively (around 50ms is about right)

  _concurrent_mark_remark_times_ms->add(0.05);

  _concurrent_mark_cleanup_times_ms->add(0.20);

}

double G1Analytics::get_new_prediction(TruncatedSeq const* seq) const {

  return _predictor->get_new_prediction(seq);

}

size_t G1Analytics::get_new_size_prediction(TruncatedSeq const* seq) const {

  return (size_t)get_new_prediction(seq);

}

int G1Analytics::num_alloc_rate_ms() const {

  return _alloc_rate_ms_seq->num();

}

void G1Analytics::report_concurrent_mark_remark_times_ms(double ms) {

  _concurrent_mark_remark_times_ms->add(ms);

}

void G1Analytics::report_alloc_rate_ms(double alloc_rate) {

  _alloc_rate_ms_seq->add(alloc_rate);

}

void G1Analytics::compute_pause_time_ratio(double interval_ms, double pause_time_ms) {

  _recent_avg_pause_time_ratio = _recent_gc_times_ms->sum() / interval_ms;

  if (_recent_avg_pause_time_ratio < 0.0 ||

      (_recent_avg_pause_time_ratio - 1.0 > 0.0)) {

    // Clip ratio between 0.0 and 1.0, and continue. This will be fixed in

    // CR 6902692 by redoing the manner in which the ratio is incrementally computed.

    if (_recent_avg_pause_time_ratio < 0.0) {

      _recent_avg_pause_time_ratio = 0.0;

    } else {

      assert(_recent_avg_pause_time_ratio - 1.0 > 0.0, "Ctl-point invariant");

      _recent_avg_pause_time_ratio = 1.0;

    }

  }

  // Compute the ratio of just this last pause time to the entire time range stored

  // in the vectors. Comparing this pause to the entire range, rather than only the

  // most recent interval, has the effect of smoothing over a possible transient 'burst'

  // of more frequent pauses that don't really reflect a change in heap occupancy.

  // This reduces the likelihood of a needless heap expansion being triggered.

  _last_pause_time_ratio =

    (pause_time_ms * _recent_prev_end_times_for_all_gcs_sec->num()) / interval_ms;

}

void G1Analytics::report_cost_per_log_buffer_entry_ms(double cost_per_log_buffer_entry_ms) {

  _cost_per_log_buffer_entry_ms_seq->add(cost_per_log_buffer_entry_ms);

}

void G1Analytics::report_cost_scan_hcc(double cost_scan_hcc) {

  _cost_scan_hcc_seq->add(cost_scan_hcc);

}

void G1Analytics::report_cost_per_remset_card_ms(double cost_per_remset_card_ms, bool for_young_gc) {

  if (for_young_gc) {

    _young_only_cost_per_remset_card_ms_seq->add(cost_per_remset_card_ms);

  } else {

    _mixed_cost_per_remset_card_ms_seq->add(cost_per_remset_card_ms);

  }

}

void G1Analytics::report_cards_per_entry_ratio(double cards_per_entry_ratio, bool for_young_gc) {

  if (for_young_gc) {

    _young_cards_per_entry_ratio_seq->add(cards_per_entry_ratio);

  } else {

    _mixed_cards_per_entry_ratio_seq->add(cards_per_entry_ratio);

  }

}

void G1Analytics::report_rs_length_diff(double rs_length_diff) {

  _rs_length_diff_seq->add(rs_length_diff);

}

void G1Analytics::report_cost_per_byte_ms(double cost_per_byte_ms, bool mark_or_rebuild_in_progress) {

  if (mark_or_rebuild_in_progress) {

    _cost_per_byte_ms_during_cm_seq->add(cost_per_byte_ms);

  } else {

    _cost_per_byte_ms_seq->add(cost_per_byte_ms);

  }

}

void G1Analytics::report_young_other_cost_per_region_ms(double other_cost_per_region_ms) {

  _young_other_cost_per_region_ms_seq->add(other_cost_per_region_ms);

}

void G1Analytics::report_non_young_other_cost_per_region_ms(double other_cost_per_region_ms) {

  _non_young_other_cost_per_region_ms_seq->add(other_cost_per_region_ms);

}

void G1Analytics::report_constant_other_time_ms(double constant_other_time_ms) {

  _constant_other_time_ms_seq->add(constant_other_time_ms);

}

void G1Analytics::report_pending_cards(double pending_cards) {

  _pending_cards_seq->add(pending_cards);

}

void G1Analytics::report_rs_length(double rs_length) {

  _rs_length_seq->add(rs_length);

}

size_t G1Analytics::predict_rs_length_diff() const {

  return get_new_size_prediction(_rs_length_diff_seq);

}

double G1Analytics::predict_alloc_rate_ms() const {

  return get_new_prediction(_alloc_rate_ms_seq);

}

double G1Analytics::predict_cost_per_log_buffer_entry_ms() const {

  return get_new_prediction(_cost_per_log_buffer_entry_ms_seq);

}

double G1Analytics::predict_scan_hcc_ms() const {

  return get_new_prediction(_cost_scan_hcc_seq);

}

double G1Analytics::predict_rs_update_time_ms(size_t pending_cards) const {

  return pending_cards * predict_cost_per_log_buffer_entry_ms() + predict_scan_hcc_ms();

}

double G1Analytics::predict_young_cards_per_entry_ratio() const {

  return get_new_prediction(_young_cards_per_entry_ratio_seq);

}

double G1Analytics::predict_mixed_cards_per_entry_ratio() const {

  if (_mixed_cards_per_entry_ratio_seq->num() < 2) {

    return predict_young_cards_per_entry_ratio();

  } else {

    return get_new_prediction(_mixed_cards_per_entry_ratio_seq);

  }

}

size_t G1Analytics::predict_card_num(size_t rs_length, bool for_young_gc) const {

  if (for_young_gc) {

    return (size_t) (rs_length * predict_young_cards_per_entry_ratio());

  } else {

    return (size_t) (rs_length * predict_mixed_cards_per_entry_ratio());

  }

}

double G1Analytics::predict_rs_scan_time_ms(size_t card_num, bool for_young_gc) const {

  if (for_young_gc) {

    return card_num * get_new_prediction(_young_only_cost_per_remset_card_ms_seq);

  } else {

    return predict_mixed_rs_scan_time_ms(card_num);

  }

}

double G1Analytics::predict_mixed_rs_scan_time_ms(size_t card_num) const {

  if (_mixed_cost_per_remset_card_ms_seq->num() < 3) {

    return card_num * get_new_prediction(_young_only_cost_per_remset_card_ms_seq);

  } else {

    return card_num * get_new_prediction(_mixed_cost_per_remset_card_ms_seq);

  }

}

double G1Analytics::predict_object_copy_time_ms_during_cm(size_t bytes_to_copy) const {

  if (_cost_per_byte_ms_during_cm_seq->num() < 3) {

    return (1.1 * bytes_to_copy) * get_new_prediction(_cost_per_byte_ms_seq);

  } else {

    return bytes_to_copy * get_new_prediction(_cost_per_byte_ms_during_cm_seq);

  }

}

double G1Analytics::predict_object_copy_time_ms(size_t bytes_to_copy, bool during_concurrent_mark) const {

  if (during_concurrent_mark) {

    return predict_object_copy_time_ms_during_cm(bytes_to_copy);

  } else {

    return bytes_to_copy * get_new_prediction(_cost_per_byte_ms_seq);

  }

}

double G1Analytics::predict_cost_per_byte_ms() const {

  return get_new_prediction(_cost_per_byte_ms_seq);

}

double G1Analytics::predict_constant_other_time_ms() const {

  return get_new_prediction(_constant_other_time_ms_seq);

}

double G1Analytics::predict_young_other_time_ms(size_t young_num) const {

  return young_num * get_new_prediction(_young_other_cost_per_region_ms_seq);

}

double G1Analytics::predict_non_young_other_time_ms(size_t non_young_num) const {

  return non_young_num * get_new_prediction(_non_young_other_cost_per_region_ms_seq);

}

double G1Analytics::predict_remark_time_ms() const {

  return get_new_prediction(_concurrent_mark_remark_times_ms);

}

double G1Analytics::predict_cleanup_time_ms() const {

  return get_new_prediction(_concurrent_mark_cleanup_times_ms);

}

size_t G1Analytics::predict_rs_length() const {

  return get_new_size_prediction(_rs_length_seq);

}

size_t G1Analytics::predict_pending_cards() const {

  return get_new_size_prediction(_pending_cards_seq);

}

double G1Analytics::last_known_gc_end_time_sec() const {

  return _recent_prev_end_times_for_all_gcs_sec->oldest();

}

void G1Analytics::update_recent_gc_times(double end_time_sec,

                                         double pause_time_ms) {

  _recent_gc_times_ms->add(pause_time_ms);

  _recent_prev_end_times_for_all_gcs_sec->add(end_time_sec);

  _prev_collection_pause_end_ms = end_time_sec * 1000.0;

}

void G1Analytics::report_concurrent_mark_cleanup_times_ms(double ms) {

  _concurrent_mark_cleanup_times_ms->add(ms);

}