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
187
188
189
190
191
192
193
194
195
|
package flamegraph
import (
"encoding/json"
"ior/internal/event"
"slices"
"sort"
"strings"
"sync"
"sync/atomic"
)
const liveTrieMinFraction = 0.001
type trieSnapshot struct {
Name string `json:"n"`
Value uint64 `json:"v"`
Total uint64 `json:"t"`
Children []*trieSnapshot `json:"c,omitempty"`
}
// LiveTrie is a thread-safe, append-only trie used for live flamegraph snapshots.
type LiveTrie struct {
mu sync.RWMutex
root *trieNode
maxDepth int
version atomic.Uint64
fields []string
countField string
// Snapshot cache avoids recomputing JSON when version is unchanged.
cacheMu sync.Mutex
cacheVersion uint64
cacheJSON []byte
}
// NewLiveTrie constructs an empty live trie with the configured frame/count fields.
func NewLiveTrie(fields []string, countField string) *LiveTrie {
return &LiveTrie{
root: &trieNode{
childMap: make(map[string]*trieNode),
},
fields: slices.Clone(fields),
countField: countField,
}
}
func (lt *LiveTrie) addLocked(frames []string, value uint64) {
node := lt.root
for _, frame := range frames {
if node.childMap == nil {
node.childMap = make(map[string]*trieNode)
}
child, ok := node.childMap[frame]
if !ok {
child = &trieNode{
name: frame,
childMap: make(map[string]*trieNode),
}
node.children = append(node.children, child)
node.childMap[frame] = child
}
node = child
}
node.value += value
if len(frames) > lt.maxDepth {
lt.maxDepth = len(frames)
}
}
// Ingest adds one event pair into the live trie and recycles the pair.
func (lt *LiveTrie) Ingest(ep *event.Pair) {
record := eventPairToRecord(ep)
frames := lt.buildFrames(record)
value := record.Cnt.ValueByName(lt.countField)
lt.mu.Lock()
lt.addLocked(frames, value)
lt.version.Add(1)
lt.mu.Unlock()
ep.Recycle()
}
// Version returns the current ingest version of the trie.
func (lt *LiveTrie) Version() uint64 {
return lt.version.Load()
}
// SnapshotJSON returns a compact JSON snapshot for the current trie version.
func (lt *LiveTrie) SnapshotJSON() ([]byte, uint64) {
version := lt.Version()
lt.cacheMu.Lock()
if lt.cacheVersion == version && lt.cacheJSON != nil {
cached := slices.Clone(lt.cacheJSON)
lt.cacheMu.Unlock()
return cached, version
}
lt.cacheMu.Unlock()
lt.mu.RLock()
version = lt.version.Load()
rootTotal := subtreeTotal(lt.root)
snapshot := buildSnapshot(lt.root, 0, liveTrieMinFraction, rootTotal)
lt.mu.RUnlock()
payload, err := json.Marshal(snapshot)
if err != nil {
return []byte(`{}`), version
}
lt.cacheMu.Lock()
lt.cacheVersion = version
lt.cacheJSON = slices.Clone(payload)
lt.cacheMu.Unlock()
return payload, version
}
func eventPairToRecord(ep *event.Pair) IterRecord {
return IterRecord{
Path: ep.FileName(),
TraceID: ep.EnterEv.GetTraceId(),
Comm: strings.TrimSpace(ep.Comm),
Pid: ep.EnterEv.GetPid(),
Tid: ep.EnterEv.GetTid(),
Flags: ep.Flags(),
Cnt: Counter{
Count: 1,
Duration: ep.Duration,
DurationToPrev: ep.DurationToPrev,
Bytes: ep.Bytes,
},
}
}
func (lt *LiveTrie) buildFrames(record IterRecord) []string {
frames := make([]string, 0, len(lt.fields))
for _, fieldName := range lt.fields {
value, err := record.StringByName(fieldName)
if err != nil {
continue
}
for _, part := range strings.Split(value, ";") {
if part != "" {
frames = append(frames, part)
}
}
}
return frames
}
func subtreeTotal(node *trieNode) uint64 {
total := node.value
for _, child := range node.children {
total += subtreeTotal(child)
}
return total
}
func buildSnapshot(node *trieNode, depth int, minFraction float64, rootTotal uint64) *trieSnapshot {
snapshot, _ := buildSnapshotWithTotal(node, depth, minFraction, rootTotal)
return snapshot
}
func buildSnapshotWithTotal(node *trieNode, depth int, minFraction float64, rootTotal uint64) (*trieSnapshot, uint64) {
total := node.value
children := slices.Clone(node.children)
sort.Slice(children, func(i, j int) bool {
return children[i].name < children[j].name
})
childSnapshots := make([]*trieSnapshot, 0, len(children))
for _, child := range children {
childSnapshot, childTotal := buildSnapshotWithTotal(child, depth+1, minFraction, rootTotal)
total += childTotal
if childSnapshot != nil {
childSnapshots = append(childSnapshots, childSnapshot)
}
}
if depth > 0 && rootTotal > 0 && float64(total)/float64(rootTotal) < minFraction {
return nil, total
}
snapshot := &trieSnapshot{
Name: node.name,
Value: node.value,
Total: total,
}
if len(childSnapshots) > 0 {
snapshot.Children = childSnapshots
}
return snapshot, total
}
|
