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// Copyright 2023 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package main
import (
"fmt"
"internal/trace"
"internal/trace/traceviewer"
"strings"
)
// generator is an interface for generating a JSON trace for the trace viewer
// from a trace. Each method in this interface is a handler for a kind of event
// that is interesting to render in the UI via the JSON trace.
type generator interface {
// Global parts.
Sync() // Notifies the generator of an EventSync event.
StackSample(ctx *traceContext, ev *trace.Event)
GlobalRange(ctx *traceContext, ev *trace.Event)
GlobalMetric(ctx *traceContext, ev *trace.Event)
// Goroutine parts.
GoroutineLabel(ctx *traceContext, ev *trace.Event)
GoroutineRange(ctx *traceContext, ev *trace.Event)
GoroutineTransition(ctx *traceContext, ev *trace.Event)
// Proc parts.
ProcRange(ctx *traceContext, ev *trace.Event)
ProcTransition(ctx *traceContext, ev *trace.Event)
// User annotations.
Log(ctx *traceContext, ev *trace.Event)
// Finish indicates the end of the trace and finalizes generation.
Finish(ctx *traceContext)
}
// runGenerator produces a trace into ctx by running the generator over the parsed trace.
func runGenerator(ctx *traceContext, g generator, parsed *parsedTrace, opts *genOpts) {
for i := range parsed.events {
ev := &parsed.events[i]
switch ev.Kind() {
case trace.EventSync:
g.Sync()
case trace.EventStackSample:
g.StackSample(ctx, ev)
case trace.EventRangeBegin, trace.EventRangeActive, trace.EventRangeEnd:
r := ev.Range()
switch r.Scope.Kind {
case trace.ResourceGoroutine:
g.GoroutineRange(ctx, ev)
case trace.ResourceProc:
g.ProcRange(ctx, ev)
case trace.ResourceNone:
g.GlobalRange(ctx, ev)
}
case trace.EventMetric:
g.GlobalMetric(ctx, ev)
case trace.EventLabel:
l := ev.Label()
if l.Resource.Kind == trace.ResourceGoroutine {
g.GoroutineLabel(ctx, ev)
}
case trace.EventStateTransition:
switch ev.StateTransition().Resource.Kind {
case trace.ResourceProc:
g.ProcTransition(ctx, ev)
case trace.ResourceGoroutine:
g.GoroutineTransition(ctx, ev)
}
case trace.EventLog:
g.Log(ctx, ev)
}
}
for i, task := range opts.tasks {
emitTask(ctx, task, i)
if opts.mode&traceviewer.ModeGoroutineOriented != 0 {
for _, region := range task.Regions {
emitRegion(ctx, region)
}
}
}
g.Finish(ctx)
}
// emitTask emits information about a task into the trace viewer's event stream.
//
// sortIndex sets the order in which this task will appear related to other tasks,
// lowest first.
func emitTask(ctx *traceContext, task *trace.UserTaskSummary, sortIndex int) {
// Collect information about the task.
var startStack, endStack trace.Stack
var startG, endG trace.GoID
startTime, endTime := ctx.startTime, ctx.endTime
if task.Start != nil {
startStack = task.Start.Stack()
startG = task.Start.Goroutine()
startTime = task.Start.Time()
}
if task.End != nil {
endStack = task.End.Stack()
endG = task.End.Goroutine()
endTime = task.End.Time()
}
arg := struct {
ID uint64 `json:"id"`
StartG uint64 `json:"start_g,omitempty"`
EndG uint64 `json:"end_g,omitempty"`
}{
ID: uint64(task.ID),
StartG: uint64(startG),
EndG: uint64(endG),
}
// Emit the task slice and notify the emitter of the task.
ctx.Task(uint64(task.ID), fmt.Sprintf("T%d %s", task.ID, task.Name), sortIndex)
ctx.TaskSlice(traceviewer.SliceEvent{
Name: task.Name,
Ts: ctx.elapsed(startTime),
Dur: endTime.Sub(startTime),
Resource: uint64(task.ID),
Stack: ctx.Stack(viewerFrames(startStack)),
EndStack: ctx.Stack(viewerFrames(endStack)),
Arg: arg,
})
// Emit an arrow from the parent to the child.
if task.Parent != nil && task.Start != nil && task.Start.Kind() == trace.EventTaskBegin {
ctx.TaskArrow(traceviewer.ArrowEvent{
Name: "newTask",
Start: ctx.elapsed(task.Start.Time()),
End: ctx.elapsed(task.Start.Time()),
FromResource: uint64(task.Parent.ID),
ToResource: uint64(task.ID),
FromStack: ctx.Stack(viewerFrames(task.Start.Stack())),
})
}
}
// emitRegion emits goroutine-based slice events to the UI. The caller
// must be emitting for a goroutine-oriented trace.
//
// TODO(mknyszek): Make regions part of the regular generator loop and
// treat them like ranges so that we can emit regions in traces oriented
// by proc or thread.
func emitRegion(ctx *traceContext, region *trace.UserRegionSummary) {
if region.Name == "" {
return
}
// Collect information about the region.
var startStack, endStack trace.Stack
goroutine := trace.NoGoroutine
startTime, endTime := ctx.startTime, ctx.endTime
if region.Start != nil {
startStack = region.Start.Stack()
startTime = region.Start.Time()
goroutine = region.Start.Goroutine()
}
if region.End != nil {
endStack = region.End.Stack()
endTime = region.End.Time()
goroutine = region.End.Goroutine()
}
if goroutine == trace.NoGoroutine {
return
}
arg := struct {
TaskID uint64 `json:"taskid"`
}{
TaskID: uint64(region.TaskID),
}
ctx.AsyncSlice(traceviewer.AsyncSliceEvent{
SliceEvent: traceviewer.SliceEvent{
Name: region.Name,
Ts: ctx.elapsed(startTime),
Dur: endTime.Sub(startTime),
Resource: uint64(goroutine),
Stack: ctx.Stack(viewerFrames(startStack)),
EndStack: ctx.Stack(viewerFrames(endStack)),
Arg: arg,
},
Category: "Region",
Scope: fmt.Sprintf("%x", region.TaskID),
TaskColorIndex: uint64(region.TaskID),
})
}
// Building blocks for generators.
// stackSampleGenerator implements a generic handler for stack sample events.
// The provided resource is the resource the stack sample should count against.
type stackSampleGenerator[R resource] struct {
// getResource is a function to extract a resource ID from a stack sample event.
getResource func(*trace.Event) R
}
// StackSample implements a stack sample event handler. It expects ev to be one such event.
func (g *stackSampleGenerator[R]) StackSample(ctx *traceContext, ev *trace.Event) {
id := g.getResource(ev)
if id == R(noResource) {
// We have nowhere to put this in the UI.
return
}
ctx.Instant(traceviewer.InstantEvent{
Name: "CPU profile sample",
Ts: ctx.elapsed(ev.Time()),
Resource: uint64(id),
Stack: ctx.Stack(viewerFrames(ev.Stack())),
})
}
// globalRangeGenerator implements a generic handler for EventRange* events that pertain
// to trace.ResourceNone (the global scope).
type globalRangeGenerator struct {
ranges map[string]activeRange
seenSync bool
}
// Sync notifies the generator of an EventSync event.
func (g *globalRangeGenerator) Sync() {
g.seenSync = true
}
// GlobalRange implements a handler for EventRange* events whose Scope.Kind is ResourceNone.
// It expects ev to be one such event.
func (g *globalRangeGenerator) GlobalRange(ctx *traceContext, ev *trace.Event) {
if g.ranges == nil {
g.ranges = make(map[string]activeRange)
}
r := ev.Range()
switch ev.Kind() {
case trace.EventRangeBegin:
g.ranges[r.Name] = activeRange{ev.Time(), ev.Stack()}
case trace.EventRangeActive:
// If we've seen a Sync event, then Active events are always redundant.
if !g.seenSync {
// Otherwise, they extend back to the start of the trace.
g.ranges[r.Name] = activeRange{ctx.startTime, ev.Stack()}
}
case trace.EventRangeEnd:
// Only emit GC events, because we have nowhere to
// put other events.
ar := g.ranges[r.Name]
if strings.Contains(r.Name, "GC") {
ctx.Slice(traceviewer.SliceEvent{
Name: r.Name,
Ts: ctx.elapsed(ar.time),
Dur: ev.Time().Sub(ar.time),
Resource: trace.GCP,
Stack: ctx.Stack(viewerFrames(ar.stack)),
EndStack: ctx.Stack(viewerFrames(ev.Stack())),
})
}
delete(g.ranges, r.Name)
}
}
// Finish flushes any outstanding ranges at the end of the trace.
func (g *globalRangeGenerator) Finish(ctx *traceContext) {
for name, ar := range g.ranges {
if !strings.Contains(name, "GC") {
continue
}
ctx.Slice(traceviewer.SliceEvent{
Name: name,
Ts: ctx.elapsed(ar.time),
Dur: ctx.endTime.Sub(ar.time),
Resource: trace.GCP,
Stack: ctx.Stack(viewerFrames(ar.stack)),
})
}
}
// globalMetricGenerator implements a generic handler for Metric events.
type globalMetricGenerator struct {
}
// GlobalMetric implements an event handler for EventMetric events. ev must be one such event.
func (g *globalMetricGenerator) GlobalMetric(ctx *traceContext, ev *trace.Event) {
m := ev.Metric()
switch m.Name {
case "/memory/classes/heap/objects:bytes":
ctx.HeapAlloc(ctx.elapsed(ev.Time()), m.Value.Uint64())
case "/gc/heap/goal:bytes":
ctx.HeapGoal(ctx.elapsed(ev.Time()), m.Value.Uint64())
case "/sched/gomaxprocs:threads":
ctx.Gomaxprocs(m.Value.Uint64())
}
}
// procRangeGenerator implements a generic handler for EventRange* events whose Scope.Kind is
// ResourceProc.
type procRangeGenerator struct {
ranges map[trace.Range]activeRange
seenSync bool
}
// Sync notifies the generator of an EventSync event.
func (g *procRangeGenerator) Sync() {
g.seenSync = true
}
// ProcRange implements a handler for EventRange* events whose Scope.Kind is ResourceProc.
// It expects ev to be one such event.
func (g *procRangeGenerator) ProcRange(ctx *traceContext, ev *trace.Event) {
if g.ranges == nil {
g.ranges = make(map[trace.Range]activeRange)
}
r := ev.Range()
switch ev.Kind() {
case trace.EventRangeBegin:
g.ranges[r] = activeRange{ev.Time(), ev.Stack()}
case trace.EventRangeActive:
// If we've seen a Sync event, then Active events are always redundant.
if !g.seenSync {
// Otherwise, they extend back to the start of the trace.
g.ranges[r] = activeRange{ctx.startTime, ev.Stack()}
}
case trace.EventRangeEnd:
// Emit proc-based ranges.
ar := g.ranges[r]
ctx.Slice(traceviewer.SliceEvent{
Name: r.Name,
Ts: ctx.elapsed(ar.time),
Dur: ev.Time().Sub(ar.time),
Resource: uint64(r.Scope.Proc()),
Stack: ctx.Stack(viewerFrames(ar.stack)),
EndStack: ctx.Stack(viewerFrames(ev.Stack())),
})
delete(g.ranges, r)
}
}
// Finish flushes any outstanding ranges at the end of the trace.
func (g *procRangeGenerator) Finish(ctx *traceContext) {
for r, ar := range g.ranges {
ctx.Slice(traceviewer.SliceEvent{
Name: r.Name,
Ts: ctx.elapsed(ar.time),
Dur: ctx.endTime.Sub(ar.time),
Resource: uint64(r.Scope.Proc()),
Stack: ctx.Stack(viewerFrames(ar.stack)),
})
}
}
// activeRange represents an active EventRange* range.
type activeRange struct {
time trace.Time
stack trace.Stack
}
// completedRange represents a completed EventRange* range.
type completedRange struct {
name string
startTime trace.Time
endTime trace.Time
startStack trace.Stack
endStack trace.Stack
arg any
}
type logEventGenerator[R resource] struct {
// getResource is a function to extract a resource ID from a Log event.
getResource func(*trace.Event) R
}
// Log implements a log event handler. It expects ev to be one such event.
func (g *logEventGenerator[R]) Log(ctx *traceContext, ev *trace.Event) {
id := g.getResource(ev)
if id == R(noResource) {
// We have nowhere to put this in the UI.
return
}
// Construct the name to present.
log := ev.Log()
name := log.Message
if log.Category != "" {
name = "[" + log.Category + "] " + name
}
// Emit an instant event.
ctx.Instant(traceviewer.InstantEvent{
Name: name,
Ts: ctx.elapsed(ev.Time()),
Category: "user event",
Resource: uint64(id),
Stack: ctx.Stack(viewerFrames(ev.Stack())),
})
}