1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
|
// Copyright 2014 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef V8_HEAP_GC_IDLE_TIME_HANDLER_H_
#define V8_HEAP_GC_IDLE_TIME_HANDLER_H_
#include "src/globals.h"
namespace v8 {
namespace internal {
enum GCIdleTimeActionType {
DONE,
DO_NOTHING,
DO_INCREMENTAL_MARKING,
DO_SCAVENGE,
DO_FULL_GC,
DO_FINALIZE_SWEEPING
};
class GCIdleTimeAction {
public:
static GCIdleTimeAction Done() {
GCIdleTimeAction result;
result.type = DONE;
result.parameter = 0;
return result;
}
static GCIdleTimeAction Nothing() {
GCIdleTimeAction result;
result.type = DO_NOTHING;
result.parameter = 0;
return result;
}
static GCIdleTimeAction IncrementalMarking(intptr_t step_size) {
GCIdleTimeAction result;
result.type = DO_INCREMENTAL_MARKING;
result.parameter = step_size;
return result;
}
static GCIdleTimeAction Scavenge() {
GCIdleTimeAction result;
result.type = DO_SCAVENGE;
result.parameter = 0;
return result;
}
static GCIdleTimeAction FullGC() {
GCIdleTimeAction result;
result.type = DO_FULL_GC;
result.parameter = 0;
return result;
}
static GCIdleTimeAction FinalizeSweeping() {
GCIdleTimeAction result;
result.type = DO_FINALIZE_SWEEPING;
result.parameter = 0;
return result;
}
void Print();
GCIdleTimeActionType type;
intptr_t parameter;
};
class GCTracer;
// The idle time handler makes decisions about which garbage collection
// operations are executing during IdleNotification.
class GCIdleTimeHandler {
public:
// If we haven't recorded any incremental marking events yet, we carefully
// mark with a conservative lower bound for the marking speed.
static const size_t kInitialConservativeMarkingSpeed = 100 * KB;
// Maximum marking step size returned by EstimateMarkingStepSize.
static const size_t kMaximumMarkingStepSize = 700 * MB;
// We have to make sure that we finish the IdleNotification before
// idle_time_in_ms. Hence, we conservatively prune our workload estimate.
static const double kConservativeTimeRatio;
// If we haven't recorded any mark-compact events yet, we use
// conservative lower bound for the mark-compact speed.
static const size_t kInitialConservativeMarkCompactSpeed = 2 * MB;
// Maximum mark-compact time returned by EstimateMarkCompactTime.
static const size_t kMaxMarkCompactTimeInMs;
// Minimum time to finalize sweeping phase. The main thread may wait for
// sweeper threads.
static const size_t kMinTimeForFinalizeSweeping;
// Number of idle mark-compact events, after which idle handler will finish
// idle round.
static const int kMaxMarkCompactsInIdleRound;
// Number of scavenges that will trigger start of new idle round.
static const int kIdleScavengeThreshold;
// Heap size threshold below which we prefer mark-compact over incremental
// step.
static const size_t kSmallHeapSize = 4 * kPointerSize * MB;
// That is the maximum idle time we will have during frame rendering.
static const size_t kMaxFrameRenderingIdleTime = 16;
// If we haven't recorded any scavenger events yet, we use a conservative
// lower bound for the scavenger speed.
static const size_t kInitialConservativeScavengeSpeed = 100 * KB;
struct HeapState {
int contexts_disposed;
size_t size_of_objects;
bool incremental_marking_stopped;
bool can_start_incremental_marking;
bool sweeping_in_progress;
size_t mark_compact_speed_in_bytes_per_ms;
size_t incremental_marking_speed_in_bytes_per_ms;
size_t scavenge_speed_in_bytes_per_ms;
size_t used_new_space_size;
size_t new_space_capacity;
size_t new_space_allocation_throughput_in_bytes_per_ms;
};
GCIdleTimeHandler()
: mark_compacts_since_idle_round_started_(0),
scavenges_since_last_idle_round_(0) {}
GCIdleTimeAction Compute(size_t idle_time_in_ms, HeapState heap_state);
void NotifyIdleMarkCompact() {
if (mark_compacts_since_idle_round_started_ < kMaxMarkCompactsInIdleRound) {
++mark_compacts_since_idle_round_started_;
if (mark_compacts_since_idle_round_started_ ==
kMaxMarkCompactsInIdleRound) {
scavenges_since_last_idle_round_ = 0;
}
}
}
void NotifyScavenge() { ++scavenges_since_last_idle_round_; }
static size_t EstimateMarkingStepSize(size_t idle_time_in_ms,
size_t marking_speed_in_bytes_per_ms);
static size_t EstimateMarkCompactTime(
size_t size_of_objects, size_t mark_compact_speed_in_bytes_per_ms);
static bool ShouldDoMarkCompact(size_t idle_time_in_ms,
size_t size_of_objects,
size_t mark_compact_speed_in_bytes_per_ms);
static bool ShouldDoScavenge(
size_t idle_time_in_ms, size_t new_space_size, size_t used_new_space_size,
size_t scavenger_speed_in_bytes_per_ms,
size_t new_space_allocation_throughput_in_bytes_per_ms);
private:
void StartIdleRound() { mark_compacts_since_idle_round_started_ = 0; }
bool IsMarkCompactIdleRoundFinished() {
return mark_compacts_since_idle_round_started_ ==
kMaxMarkCompactsInIdleRound;
}
bool EnoughGarbageSinceLastIdleRound() {
return scavenges_since_last_idle_round_ >= kIdleScavengeThreshold;
}
int mark_compacts_since_idle_round_started_;
int scavenges_since_last_idle_round_;
DISALLOW_COPY_AND_ASSIGN(GCIdleTimeHandler);
};
} // namespace internal
} // namespace v8
#endif // V8_HEAP_GC_IDLE_TIME_HANDLER_H_
|
