1 /*
2 * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #ifndef SHARE_VM_GC_G1_G1IHOPCONTROL_HPP
26 #define SHARE_VM_GC_G1_G1IHOPCONTROL_HPP
27
28 #include "memory/allocation.hpp"
29 #include "utilities/numberSeq.hpp"
30
31 class G1Predictions;
32
33 // Base class for algorithms that calculate the heap occupancy at which
34 // concurrent marking should start. This heap usage threshold should be relative
35 // to old gen size.
36 class G1IHOPControl : public CHeapObj<mtGC> {
37 protected:
38 // The initial IHOP value relative to the target occupancy.
39 double _initial_ihop_percent;
40 // The target maximum occupancy of the heap.
41 size_t _target_occupancy;
42
43 // Initialize an instance with the initial IHOP value in percent and the target
44 // occupancy. The target occupancy is the number of bytes when marking should
45 // be finished and reclaim started.
46 G1IHOPControl(double initial_ihop_percent, size_t target_occupancy);
47 public:
48 virtual ~G1IHOPControl() { }
49
50 // Get the current non-young occupancy at which concurrent marking should start.
51 virtual size_t get_conc_mark_start_threshold() = 0;
52
53 // Update information about time during which allocations in the Java heap occurred,
54 // how large these allocations were in bytes, and an additional buffer.
55 // The allocations should contain any amount of space made unusable for further
56 // allocation, e.g. any waste caused by TLAB allocation, space at the end of
57 // humongous objects that can not be used for allocation, etc.
58 // Together with the target occupancy, this additional buffer should contain the
59 // difference between old gen size and total heap size at the start of reclamation,
60 // and space required for that reclamation.
61 virtual void update_allocation_info(double allocation_time_s, size_t allocated_bytes, size_t additional_buffer_size) = 0;
62 // Update the time spent in the mutator beginning from the end of initial mark to
63 // the first mixed gc.
64 virtual void update_marking_length(double marking_length_s) = 0;
65
66 virtual void print() = 0;
67 };
68
69 // The returned concurrent mark starting occupancy threshold is a fixed value
70 // relative to the maximum heap size.
71 class G1StaticIHOPControl : public G1IHOPControl {
72 // Most recent complete mutator allocation period in seconds.
73 double _last_allocation_time_s;
74 // Amount of bytes allocated during _last_allocation_time_s.
75 size_t _last_allocated_bytes;
76 // Most recent mutator time between the end of initial mark to the start of the
77 // first mixed gc.
78 double _last_marking_length_s;
79 public:
80 G1StaticIHOPControl(double ihop_percent, size_t target_occupancy);
81
82 size_t get_conc_mark_start_threshold() { return (size_t) (_initial_ihop_percent * _target_occupancy / 100.0); }
83
84 virtual void update_allocation_info(double allocation_time_s, size_t allocated_bytes, size_t additional_buffer_size) {
85 assert(allocation_time_s >= 0.0, "Allocation time must be positive but is %.3f", allocation_time_s);
86 _last_allocation_time_s = allocation_time_s;
87 _last_allocated_bytes = allocated_bytes;
88 }
89
90 virtual void update_marking_length(double marking_length_s) {
91 assert(marking_length_s > 0.0, "Marking length must be larger than zero but is %.3f", marking_length_s);
92 _last_marking_length_s = marking_length_s;
93 }
94
95 virtual void print();
96 #ifndef PRODUCT
97 static void test();
98 #endif
99 };
100
101 class G1AdaptiveIHOPControl : public G1IHOPControl {
102 G1Predictions const * _predictor;
103
104 TruncatedSeq _marking_times_s;
105 TruncatedSeq _allocation_rate_s;
106
107 size_t _last_allocation_bytes; // Most recent mutator allocation since last GC.
108 size_t _prev_unrestrained_young_size;
109
110 size_t _current_threshold;
111
112 // Updates _current_threshold according to internal state.
113 void recalculate();
114
115 bool have_enough_data_for_prediction() const;
116 public:
117 G1AdaptiveIHOPControl(double ihop_percent, size_t initial_target_occupancy, G1Predictions const* predictor);
118
119 virtual void set_target_occupancy(size_t target_occupancy);
120
121 virtual size_t get_conc_mark_start_threshold();
122
123 virtual void update_allocation_info(double allocation_time_s, size_t allocated_bytes, size_t additional_buffer_size);
124 virtual void update_marking_length(double marking_length_s);
125
126 virtual void print();
127 #ifndef PRODUCT
128 static void test();
129 #endif
130 };
131
132 #endif // SHARE_VM_GC_G1_G1IHOPCONTROL_HPP