Tue, 17 Oct 2017 12:58:25 +0800
merge
aoqi@0 | 1 | /* |
aoqi@0 | 2 | * Copyright (c) 2001, 2012, Oracle and/or its affiliates. All rights reserved. |
aoqi@0 | 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
aoqi@0 | 4 | * |
aoqi@0 | 5 | * This code is free software; you can redistribute it and/or modify it |
aoqi@0 | 6 | * under the terms of the GNU General Public License version 2 only, as |
aoqi@0 | 7 | * published by the Free Software Foundation. |
aoqi@0 | 8 | * |
aoqi@0 | 9 | * This code is distributed in the hope that it will be useful, but WITHOUT |
aoqi@0 | 10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
aoqi@0 | 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
aoqi@0 | 12 | * version 2 for more details (a copy is included in the LICENSE file that |
aoqi@0 | 13 | * accompanied this code). |
aoqi@0 | 14 | * |
aoqi@0 | 15 | * You should have received a copy of the GNU General Public License version |
aoqi@0 | 16 | * 2 along with this work; if not, write to the Free Software Foundation, |
aoqi@0 | 17 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
aoqi@0 | 18 | * |
aoqi@0 | 19 | * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
aoqi@0 | 20 | * or visit www.oracle.com if you need additional information or have any |
aoqi@0 | 21 | * questions. |
aoqi@0 | 22 | * |
aoqi@0 | 23 | */ |
aoqi@0 | 24 | |
aoqi@0 | 25 | #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_G1MMUTRACKER_HPP |
aoqi@0 | 26 | #define SHARE_VM_GC_IMPLEMENTATION_G1_G1MMUTRACKER_HPP |
aoqi@0 | 27 | |
aoqi@0 | 28 | #include "memory/allocation.hpp" |
aoqi@0 | 29 | #include "utilities/debug.hpp" |
aoqi@0 | 30 | |
aoqi@0 | 31 | // Keeps track of the GC work and decides when it is OK to do GC work |
aoqi@0 | 32 | // and for how long so that the MMU invariants are maintained. |
aoqi@0 | 33 | |
aoqi@0 | 34 | /***** ALL TIMES ARE IN SECS!!!!!!! *****/ |
aoqi@0 | 35 | |
aoqi@0 | 36 | // this is the "interface" |
aoqi@0 | 37 | class G1MMUTracker: public CHeapObj<mtGC> { |
aoqi@0 | 38 | protected: |
aoqi@0 | 39 | double _time_slice; |
aoqi@0 | 40 | double _max_gc_time; // this is per time slice |
aoqi@0 | 41 | |
aoqi@0 | 42 | public: |
aoqi@0 | 43 | G1MMUTracker(double time_slice, double max_gc_time); |
aoqi@0 | 44 | |
aoqi@0 | 45 | virtual void add_pause(double start, double end, bool gc_thread) = 0; |
aoqi@0 | 46 | virtual double longest_pause(double current_time) = 0; |
aoqi@0 | 47 | virtual double when_sec(double current_time, double pause_time) = 0; |
aoqi@0 | 48 | |
aoqi@0 | 49 | double max_gc_time() { |
aoqi@0 | 50 | return _max_gc_time; |
aoqi@0 | 51 | } |
aoqi@0 | 52 | |
aoqi@0 | 53 | inline bool now_max_gc(double current_time) { |
aoqi@0 | 54 | return when_sec(current_time, max_gc_time()) < 0.00001; |
aoqi@0 | 55 | } |
aoqi@0 | 56 | |
aoqi@0 | 57 | inline double when_max_gc_sec(double current_time) { |
aoqi@0 | 58 | return when_sec(current_time, max_gc_time()); |
aoqi@0 | 59 | } |
aoqi@0 | 60 | |
aoqi@0 | 61 | inline jlong when_max_gc_ms(double current_time) { |
aoqi@0 | 62 | double when = when_max_gc_sec(current_time); |
aoqi@0 | 63 | return (jlong) (when * 1000.0); |
aoqi@0 | 64 | } |
aoqi@0 | 65 | |
aoqi@0 | 66 | inline jlong when_ms(double current_time, double pause_time) { |
aoqi@0 | 67 | double when = when_sec(current_time, pause_time); |
aoqi@0 | 68 | return (jlong) (when * 1000.0); |
aoqi@0 | 69 | } |
aoqi@0 | 70 | }; |
aoqi@0 | 71 | |
aoqi@0 | 72 | class G1MMUTrackerQueueElem VALUE_OBJ_CLASS_SPEC { |
aoqi@0 | 73 | private: |
aoqi@0 | 74 | double _start_time; |
aoqi@0 | 75 | double _end_time; |
aoqi@0 | 76 | |
aoqi@0 | 77 | public: |
aoqi@0 | 78 | inline double start_time() { return _start_time; } |
aoqi@0 | 79 | inline double end_time() { return _end_time; } |
aoqi@0 | 80 | inline double duration() { return _end_time - _start_time; } |
aoqi@0 | 81 | |
aoqi@0 | 82 | G1MMUTrackerQueueElem() { |
aoqi@0 | 83 | _start_time = 0.0; |
aoqi@0 | 84 | _end_time = 0.0; |
aoqi@0 | 85 | } |
aoqi@0 | 86 | |
aoqi@0 | 87 | G1MMUTrackerQueueElem(double start_time, double end_time) { |
aoqi@0 | 88 | _start_time = start_time; |
aoqi@0 | 89 | _end_time = end_time; |
aoqi@0 | 90 | } |
aoqi@0 | 91 | }; |
aoqi@0 | 92 | |
aoqi@0 | 93 | // this is an implementation of the MMUTracker using a (fixed-size) queue |
aoqi@0 | 94 | // that keeps track of all the recent pause times |
aoqi@0 | 95 | class G1MMUTrackerQueue: public G1MMUTracker { |
aoqi@0 | 96 | private: |
aoqi@0 | 97 | enum PrivateConstants { |
aoqi@0 | 98 | QueueLength = 64 |
aoqi@0 | 99 | }; |
aoqi@0 | 100 | |
aoqi@0 | 101 | // The array keeps track of all the pauses that fall within a time |
aoqi@0 | 102 | // slice (the last time slice during which pauses took place). |
aoqi@0 | 103 | // The data structure implemented is a circular queue. |
aoqi@0 | 104 | // Head "points" to the most recent addition, tail to the oldest one. |
aoqi@0 | 105 | // The array is of fixed size and I don't think we'll need more than |
aoqi@0 | 106 | // two or three entries with the current behaviour of G1 pauses. |
aoqi@0 | 107 | // If the array is full, an easy fix is to look for the pauses with |
aoqi@0 | 108 | // the shortest gap between them and consolidate them. |
aoqi@0 | 109 | // For now, we have taken the expedient alternative of forgetting |
aoqi@0 | 110 | // the oldest entry in the event that +G1UseFixedWindowMMUTracker, thus |
aoqi@0 | 111 | // potentially violating MMU specs for some time thereafter. |
aoqi@0 | 112 | |
aoqi@0 | 113 | G1MMUTrackerQueueElem _array[QueueLength]; |
aoqi@0 | 114 | int _head_index; |
aoqi@0 | 115 | int _tail_index; |
aoqi@0 | 116 | int _no_entries; |
aoqi@0 | 117 | |
aoqi@0 | 118 | inline int trim_index(int index) { |
aoqi@0 | 119 | return (index + QueueLength) % QueueLength; |
aoqi@0 | 120 | } |
aoqi@0 | 121 | |
aoqi@0 | 122 | void remove_expired_entries(double current_time); |
aoqi@0 | 123 | double calculate_gc_time(double current_time); |
aoqi@0 | 124 | |
aoqi@0 | 125 | double longest_pause_internal(double current_time); |
aoqi@0 | 126 | double when_internal(double current_time, double pause_time); |
aoqi@0 | 127 | |
aoqi@0 | 128 | public: |
aoqi@0 | 129 | G1MMUTrackerQueue(double time_slice, double max_gc_time); |
aoqi@0 | 130 | |
aoqi@0 | 131 | virtual void add_pause(double start, double end, bool gc_thread); |
aoqi@0 | 132 | |
aoqi@0 | 133 | virtual double longest_pause(double current_time); |
aoqi@0 | 134 | virtual double when_sec(double current_time, double pause_time); |
aoqi@0 | 135 | }; |
aoqi@0 | 136 | |
aoqi@0 | 137 | #endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1MMUTRACKER_HPP |