1 /*
2 * Copyright (c) 2018, Red Hat, Inc. and/or its affiliates.
3 *
4 * This code is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License version 2 only, as
6 * published by the Free Software Foundation.
7 *
8 * This code is distributed in the hope that it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
11 * version 2 for more details (a copy is included in the LICENSE file that
12 * accompanied this code).
13 *
14 * You should have received a copy of the GNU General Public License version
15 * 2 along with this work; if not, write to the Free Software Foundation,
16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
17 *
18 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
19 * or visit www.oracle.com if you need additional information or have any
20 * questions.
21 *
22 */
23
24 #ifndef SHARE_VM_GC_SHENANDOAH_SHENANDOAHHEURISTICS_HPP
25 #define SHARE_VM_GC_SHENANDOAH_SHENANDOAHHEURISTICS_HPP
26
27 #include "gc_implementation/shenandoah/shenandoahHeap.hpp"
28 #include "gc_implementation/shenandoah/shenandoahPhaseTimings.hpp"
29 #include "memory/allocation.hpp"
30 #include "runtime/globals_extension.hpp"
31
32 #define SHENANDOAH_ERGO_DISABLE_FLAG(name) \
33 do { \
34 if (FLAG_IS_DEFAULT(name) && (name)) { \
35 log_info(gc)("Heuristics ergonomically sets -XX:-" #name); \
36 FLAG_SET_DEFAULT(name, false); \
37 } \
38 } while (0)
39
40 #define SHENANDOAH_ERGO_ENABLE_FLAG(name) \
41 do { \
42 if (FLAG_IS_DEFAULT(name) && !(name)) { \
43 log_info(gc)("Heuristics ergonomically sets -XX:+" #name); \
44 FLAG_SET_DEFAULT(name, true); \
45 } \
46 } while (0)
47
48 #define SHENANDOAH_ERGO_OVERRIDE_DEFAULT(name, value) \
49 do { \
50 if (FLAG_IS_DEFAULT(name)) { \
51 log_info(gc)("Heuristics ergonomically sets -XX:" #name "=" #value); \
52 FLAG_SET_DEFAULT(name, value); \
53 } \
54 } while (0)
55
56
57 class ShenandoahCollectionSet;
58 class ShenandoahHeapRegion;
59
60 class ShenandoahHeuristics : public CHeapObj<mtGC> {
61 protected:
62 typedef struct {
63 ShenandoahHeapRegion* _region;
64 size_t _garbage;
65 uint64_t _seqnum_last_alloc;
66 } RegionData;
67
68 typedef struct {
69 ShenandoahHeapRegion* _region;
70 size_t _connections;
71 } RegionConnections;
72
73 bool _update_refs_early;
74 bool _update_refs_adaptive;
75
76 RegionData* _region_data;
77 size_t _region_data_size;
78
79 RegionConnections* _region_connects;
80 size_t _region_connects_size;
81
82 uint _degenerated_cycles_in_a_row;
83 uint _successful_cycles_in_a_row;
84
85 size_t _bytes_in_cset;
86
87 double _last_cycle_end;
88
89 static int compare_by_garbage(RegionData a, RegionData b);
90 static int compare_by_alloc_seq_ascending(RegionData a, RegionData b);
91 static int compare_by_alloc_seq_descending(RegionData a, RegionData b);
92 static int compare_by_connects(RegionConnections a, RegionConnections b);
93
94 RegionData* get_region_data_cache(size_t num);
95
96 RegionConnections* get_region_connects_cache(size_t num);
97
98 virtual void choose_collection_set_from_regiondata(ShenandoahCollectionSet* set,
99 RegionData* data, size_t data_size,
100 size_t free) = 0;
101
102 public:
103
104 ShenandoahHeuristics();
105 virtual ~ShenandoahHeuristics();
106
107 void record_gc_start();
108
109 void record_gc_end();
110
111 virtual void record_cycle_start();
112
113 virtual void record_cycle_end();
114
115 virtual void record_phase_time(ShenandoahPhaseTimings::Phase phase, double secs);
116
117 virtual void print_thresholds();
118
119 virtual bool should_start_normal_gc() const = 0;
120
121 virtual bool should_start_update_refs();
122
123 virtual bool update_refs() const;
124
125 virtual bool should_degenerate_cycle();
126
127 virtual void record_success_concurrent();
128
129 virtual void record_success_degenerated();
130
131 virtual void record_success_full();
132
133 virtual void record_allocation_failure_gc();
134
135 virtual void record_explicit_gc();
136
137 virtual void record_peak_occupancy();
138
139 virtual void start_choose_collection_set() {
140 }
141 virtual void end_choose_collection_set() {
142 }
143
144 virtual void choose_collection_set(ShenandoahCollectionSet* collection_set);
145
146 virtual bool should_process_references();
147
148 virtual bool should_unload_classes();
149
150 virtual const char* name() = 0;
151 virtual bool is_diagnostic() = 0;
152 virtual bool is_experimental() = 0;
153 virtual void initialize();
154
155 };
156
157 #endif // SHARE_VM_GC_SHENANDOAH_SHENANDOAHHEURISTICS_HPP