// 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 (
"cmp"
"fmt"
"html/template"
"internal/trace"
"internal/trace/traceviewer"
"net/http"
"net/url"
"slices"
"sort"
"strconv"
"strings"
"time"
)
// UserRegionsHandlerFunc returns a HandlerFunc that reports all regions found in the trace.
func UserRegionsHandlerFunc(t *parsedTrace) http.HandlerFunc {
return func(w http.ResponseWriter, r *http.Request) {
// Summarize all the regions.
summary := make(map[regionFingerprint]regionStats)
for _, g := range t.summary.Goroutines {
for _, r := range g.Regions {
id := fingerprintRegion(r)
stats, ok := summary[id]
if !ok {
stats.regionFingerprint = id
}
stats.add(t, r)
summary[id] = stats
}
}
// Sort regions by PC and name.
userRegions := make([]regionStats, 0, len(summary))
for _, stats := range summary {
userRegions = append(userRegions, stats)
}
slices.SortFunc(userRegions, func(a, b regionStats) int {
if c := cmp.Compare(a.Type, b.Type); c != 0 {
return c
}
return cmp.Compare(a.Frame.PC, b.Frame.PC)
})
// Emit table.
err := templUserRegionTypes.Execute(w, userRegions)
if err != nil {
http.Error(w, fmt.Sprintf("failed to execute template: %v", err), http.StatusInternalServerError)
return
}
}
}
// regionFingerprint is a way to categorize regions that goes just one step beyond the region's Type
// by including the top stack frame.
type regionFingerprint struct {
Frame trace.StackFrame
Type string
}
func fingerprintRegion(r *trace.UserRegionSummary) regionFingerprint {
return regionFingerprint{
Frame: regionTopStackFrame(r),
Type: r.Name,
}
}
func regionTopStackFrame(r *trace.UserRegionSummary) trace.StackFrame {
var frame trace.StackFrame
if r.Start != nil && r.Start.Stack() != trace.NoStack {
r.Start.Stack().Frames(func(f trace.StackFrame) bool {
frame = f
return false
})
}
return frame
}
type regionStats struct {
regionFingerprint
Histogram traceviewer.TimeHistogram
}
func (s *regionStats) UserRegionURL() func(min, max time.Duration) string {
return func(min, max time.Duration) string {
return fmt.Sprintf("/userregion?type=%s&pc=%x&latmin=%v&latmax=%v", template.URLQueryEscaper(s.Type), s.Frame.PC, template.URLQueryEscaper(min), template.URLQueryEscaper(max))
}
}
func (s *regionStats) add(t *parsedTrace, region *trace.UserRegionSummary) {
s.Histogram.Add(regionInterval(t, region).duration())
}
var templUserRegionTypes = template.Must(template.New("").Parse(`
Regions
Regions
Below is a table containing a summary of all the user-defined regions in the trace.
Regions are grouped by the region type and the point at which the region started.
The rightmost column of the table contains a latency histogram for each region group.
Note that this histogram only counts regions that began and ended within the traced
period.
However, the "Count" column includes all regions, including those that only started
or ended during the traced period.
Regions that were active through the trace period were not recorded, and so are not
accounted for at all.
Click on the links to explore a breakdown of time spent for each region by goroutine
and user-defined task.