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
|
// 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.
#include "src/heap/gc-idle-time-handler.h"
#include "src/flags.h"
#include "src/heap/gc-tracer.h"
#include "src/utils.h"
namespace v8 {
namespace internal {
const double GCIdleTimeHandler::kConservativeTimeRatio = 0.9;
const size_t GCIdleTimeHandler::kMaxFinalIncrementalMarkCompactTimeInMs = 1000;
const double GCIdleTimeHandler::kHighContextDisposalRate = 100;
const size_t GCIdleTimeHandler::kMinTimeForOverApproximatingWeakClosureInMs = 1;
void GCIdleTimeAction::Print() {
switch (type) {
case DONE:
PrintF("done");
break;
case DO_NOTHING:
PrintF("no action");
break;
case DO_INCREMENTAL_STEP:
PrintF("incremental step");
if (additional_work) {
PrintF("; finalized marking");
}
break;
case DO_FULL_GC:
PrintF("full GC");
break;
}
}
void GCIdleTimeHeapState::Print() {
PrintF("contexts_disposed=%d ", contexts_disposed);
PrintF("contexts_disposal_rate=%f ", contexts_disposal_rate);
PrintF("size_of_objects=%" PRIuS " ", size_of_objects);
PrintF("incremental_marking_stopped=%d ", incremental_marking_stopped);
}
size_t GCIdleTimeHandler::EstimateMarkingStepSize(
double idle_time_in_ms, double marking_speed_in_bytes_per_ms) {
DCHECK(idle_time_in_ms > 0);
if (marking_speed_in_bytes_per_ms == 0) {
marking_speed_in_bytes_per_ms = kInitialConservativeMarkingSpeed;
}
double marking_step_size = marking_speed_in_bytes_per_ms * idle_time_in_ms;
if (marking_step_size >= kMaximumMarkingStepSize) {
return kMaximumMarkingStepSize;
}
return static_cast<size_t>(marking_step_size * kConservativeTimeRatio);
}
double GCIdleTimeHandler::EstimateFinalIncrementalMarkCompactTime(
size_t size_of_objects,
double final_incremental_mark_compact_speed_in_bytes_per_ms) {
if (final_incremental_mark_compact_speed_in_bytes_per_ms == 0) {
final_incremental_mark_compact_speed_in_bytes_per_ms =
kInitialConservativeFinalIncrementalMarkCompactSpeed;
}
double result =
size_of_objects / final_incremental_mark_compact_speed_in_bytes_per_ms;
return Min<double>(result, kMaxFinalIncrementalMarkCompactTimeInMs);
}
bool GCIdleTimeHandler::ShouldDoContextDisposalMarkCompact(
int contexts_disposed, double contexts_disposal_rate) {
return contexts_disposed > 0 && contexts_disposal_rate > 0 &&
contexts_disposal_rate < kHighContextDisposalRate;
}
bool GCIdleTimeHandler::ShouldDoFinalIncrementalMarkCompact(
double idle_time_in_ms, size_t size_of_objects,
double final_incremental_mark_compact_speed_in_bytes_per_ms) {
return idle_time_in_ms >=
EstimateFinalIncrementalMarkCompactTime(
size_of_objects,
final_incremental_mark_compact_speed_in_bytes_per_ms);
}
bool GCIdleTimeHandler::ShouldDoOverApproximateWeakClosure(
double idle_time_in_ms) {
// TODO(jochen): Estimate the time it will take to build the object groups.
return idle_time_in_ms >= kMinTimeForOverApproximatingWeakClosureInMs;
}
GCIdleTimeAction GCIdleTimeHandler::NothingOrDone(double idle_time_in_ms) {
if (idle_time_in_ms >= kMinBackgroundIdleTime) {
return GCIdleTimeAction::Nothing();
}
if (idle_times_which_made_no_progress_ >= kMaxNoProgressIdleTimes) {
return GCIdleTimeAction::Done();
} else {
idle_times_which_made_no_progress_++;
return GCIdleTimeAction::Nothing();
}
}
// The following logic is implemented by the controller:
// (1) If we don't have any idle time, do nothing, unless a context was
// disposed, incremental marking is stopped, and the heap is small. Then do
// a full GC.
// (2) If the context disposal rate is high and we cannot perform a full GC,
// we do nothing until the context disposal rate becomes lower.
// (3) If the new space is almost full and we can affort a scavenge or if the
// next scavenge will very likely take long, then a scavenge is performed.
// (4) If sweeping is in progress and we received a large enough idle time
// request, we finalize sweeping here.
// (5) If incremental marking is in progress, we perform a marking step. Note,
// that this currently may trigger a full garbage collection.
GCIdleTimeAction GCIdleTimeHandler::Compute(double idle_time_in_ms,
GCIdleTimeHeapState heap_state) {
if (static_cast<int>(idle_time_in_ms) <= 0) {
if (heap_state.incremental_marking_stopped) {
if (ShouldDoContextDisposalMarkCompact(
heap_state.contexts_disposed,
heap_state.contexts_disposal_rate)) {
return GCIdleTimeAction::FullGC();
}
}
return GCIdleTimeAction::Nothing();
}
// We are in a context disposal GC scenario. Don't do anything if we do not
// get the right idle signal.
if (ShouldDoContextDisposalMarkCompact(heap_state.contexts_disposed,
heap_state.contexts_disposal_rate)) {
return NothingOrDone(idle_time_in_ms);
}
if (!FLAG_incremental_marking || heap_state.incremental_marking_stopped) {
return GCIdleTimeAction::Done();
}
return GCIdleTimeAction::IncrementalStep();
}
bool GCIdleTimeHandler::Enabled() { return FLAG_incremental_marking; }
} // namespace internal
} // namespace v8
|
