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// Copyright 2014 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.
// Serving of pprof-like profiles.
package main
import (
"bufio"
"fmt"
exec "internal/execabs"
"internal/trace"
"io"
"net/http"
"os"
"path/filepath"
"runtime"
"sort"
"strconv"
"time"
"github.com/google/pprof/profile"
)
func goCmd() string {
var exeSuffix string
if runtime.GOOS == "windows" {
exeSuffix = ".exe"
}
path := filepath.Join(runtime.GOROOT(), "bin", "go"+exeSuffix)
if _, err := os.Stat(path); err == nil {
return path
}
return "go"
}
func init() {
http.HandleFunc("/io", serveSVGProfile(pprofByGoroutine(computePprofIO)))
http.HandleFunc("/block", serveSVGProfile(pprofByGoroutine(computePprofBlock)))
http.HandleFunc("/syscall", serveSVGProfile(pprofByGoroutine(computePprofSyscall)))
http.HandleFunc("/sched", serveSVGProfile(pprofByGoroutine(computePprofSched)))
http.HandleFunc("/regionio", serveSVGProfile(pprofByRegion(computePprofIO)))
http.HandleFunc("/regionblock", serveSVGProfile(pprofByRegion(computePprofBlock)))
http.HandleFunc("/regionsyscall", serveSVGProfile(pprofByRegion(computePprofSyscall)))
http.HandleFunc("/regionsched", serveSVGProfile(pprofByRegion(computePprofSched)))
}
// Record represents one entry in pprof-like profiles.
type Record struct {
stk []*trace.Frame
n uint64
time int64
}
// interval represents a time interval in the trace.
type interval struct {
begin, end int64 // nanoseconds.
}
func pprofByGoroutine(compute func(io.Writer, map[uint64][]interval, []*trace.Event) error) func(w io.Writer, r *http.Request) error {
return func(w io.Writer, r *http.Request) error {
id := r.FormValue("id")
events, err := parseEvents()
if err != nil {
return err
}
gToIntervals, err := pprofMatchingGoroutines(id, events)
if err != nil {
return err
}
return compute(w, gToIntervals, events)
}
}
func pprofByRegion(compute func(io.Writer, map[uint64][]interval, []*trace.Event) error) func(w io.Writer, r *http.Request) error {
return func(w io.Writer, r *http.Request) error {
filter, err := newRegionFilter(r)
if err != nil {
return err
}
gToIntervals, err := pprofMatchingRegions(filter)
if err != nil {
return err
}
events, _ := parseEvents()
return compute(w, gToIntervals, events)
}
}
// pprofMatchingGoroutines parses the goroutine type id string (i.e. pc)
// and returns the ids of goroutines of the matching type and its interval.
// If the id string is empty, returns nil without an error.
func pprofMatchingGoroutines(id string, events []*trace.Event) (map[uint64][]interval, error) {
if id == "" {
return nil, nil
}
pc, err := strconv.ParseUint(id, 10, 64) // id is string
if err != nil {
return nil, fmt.Errorf("invalid goroutine type: %v", id)
}
analyzeGoroutines(events)
var res map[uint64][]interval
for _, g := range gs {
if g.PC != pc {
continue
}
if res == nil {
res = make(map[uint64][]interval)
}
endTime := g.EndTime
if g.EndTime == 0 {
endTime = lastTimestamp() // the trace doesn't include the goroutine end event. Use the trace end time.
}
res[g.ID] = []interval{{begin: g.StartTime, end: endTime}}
}
if len(res) == 0 && id != "" {
return nil, fmt.Errorf("failed to find matching goroutines for id: %s", id)
}
return res, nil
}
// pprofMatchingRegions returns the time intervals of matching regions
// grouped by the goroutine id. If the filter is nil, returns nil without an error.
func pprofMatchingRegions(filter *regionFilter) (map[uint64][]interval, error) {
res, err := analyzeAnnotations()
if err != nil {
return nil, err
}
if filter == nil {
return nil, nil
}
gToIntervals := make(map[uint64][]interval)
for id, regions := range res.regions {
for _, s := range regions {
if filter.match(id, s) {
gToIntervals[s.G] = append(gToIntervals[s.G], interval{begin: s.firstTimestamp(), end: s.lastTimestamp()})
}
}
}
for g, intervals := range gToIntervals {
// in order to remove nested regions and
// consider only the outermost regions,
// first, we sort based on the start time
// and then scan through to select only the outermost regions.
sort.Slice(intervals, func(i, j int) bool {
x := intervals[i].begin
y := intervals[j].begin
if x == y {
return intervals[i].end < intervals[j].end
}
return x < y
})
var lastTimestamp int64
var n int
// select only the outermost regions.
for _, i := range intervals {
if lastTimestamp <= i.begin {
intervals[n] = i // new non-overlapping region starts.
lastTimestamp = i.end
n++
} // otherwise, skip because this region overlaps with a previous region.
}
gToIntervals[g] = intervals[:n]
}
return gToIntervals, nil
}
// computePprofIO generates IO pprof-like profile (time spent in IO wait, currently only network blocking event).
func computePprofIO(w io.Writer, gToIntervals map[uint64][]interval, events []*trace.Event) error {
prof := make(map[uint64]Record)
for _, ev := range events {
if ev.Type != trace.EvGoBlockNet || ev.Link == nil || ev.StkID == 0 || len(ev.Stk) == 0 {
continue
}
overlapping := pprofOverlappingDuration(gToIntervals, ev)
if overlapping > 0 {
rec := prof[ev.StkID]
rec.stk = ev.Stk
rec.n++
rec.time += overlapping.Nanoseconds()
prof[ev.StkID] = rec
}
}
return buildProfile(prof).Write(w)
}
// computePprofBlock generates blocking pprof-like profile (time spent blocked on synchronization primitives).
func computePprofBlock(w io.Writer, gToIntervals map[uint64][]interval, events []*trace.Event) error {
prof := make(map[uint64]Record)
for _, ev := range events {
switch ev.Type {
case trace.EvGoBlockSend, trace.EvGoBlockRecv, trace.EvGoBlockSelect,
trace.EvGoBlockSync, trace.EvGoBlockCond, trace.EvGoBlockGC:
// TODO(hyangah): figure out why EvGoBlockGC should be here.
// EvGoBlockGC indicates the goroutine blocks on GC assist, not
// on synchronization primitives.
default:
continue
}
if ev.Link == nil || ev.StkID == 0 || len(ev.Stk) == 0 {
continue
}
overlapping := pprofOverlappingDuration(gToIntervals, ev)
if overlapping > 0 {
rec := prof[ev.StkID]
rec.stk = ev.Stk
rec.n++
rec.time += overlapping.Nanoseconds()
prof[ev.StkID] = rec
}
}
return buildProfile(prof).Write(w)
}
// computePprofSyscall generates syscall pprof-like profile (time spent blocked in syscalls).
func computePprofSyscall(w io.Writer, gToIntervals map[uint64][]interval, events []*trace.Event) error {
prof := make(map[uint64]Record)
for _, ev := range events {
if ev.Type != trace.EvGoSysCall || ev.Link == nil || ev.StkID == 0 || len(ev.Stk) == 0 {
continue
}
overlapping := pprofOverlappingDuration(gToIntervals, ev)
if overlapping > 0 {
rec := prof[ev.StkID]
rec.stk = ev.Stk
rec.n++
rec.time += overlapping.Nanoseconds()
prof[ev.StkID] = rec
}
}
return buildProfile(prof).Write(w)
}
// computePprofSched generates scheduler latency pprof-like profile
// (time between a goroutine become runnable and actually scheduled for execution).
func computePprofSched(w io.Writer, gToIntervals map[uint64][]interval, events []*trace.Event) error {
prof := make(map[uint64]Record)
for _, ev := range events {
if (ev.Type != trace.EvGoUnblock && ev.Type != trace.EvGoCreate) ||
ev.Link == nil || ev.StkID == 0 || len(ev.Stk) == 0 {
continue
}
overlapping := pprofOverlappingDuration(gToIntervals, ev)
if overlapping > 0 {
rec := prof[ev.StkID]
rec.stk = ev.Stk
rec.n++
rec.time += overlapping.Nanoseconds()
prof[ev.StkID] = rec
}
}
return buildProfile(prof).Write(w)
}
// pprofOverlappingDuration returns the overlapping duration between
// the time intervals in gToIntervals and the specified event.
// If gToIntervals is nil, this simply returns the event's duration.
func pprofOverlappingDuration(gToIntervals map[uint64][]interval, ev *trace.Event) time.Duration {
if gToIntervals == nil { // No filtering.
return time.Duration(ev.Link.Ts-ev.Ts) * time.Nanosecond
}
intervals := gToIntervals[ev.G]
if len(intervals) == 0 {
return 0
}
var overlapping time.Duration
for _, i := range intervals {
if o := overlappingDuration(i.begin, i.end, ev.Ts, ev.Link.Ts); o > 0 {
overlapping += o
}
}
return overlapping
}
// serveSVGProfile serves pprof-like profile generated by prof as svg.
func serveSVGProfile(prof func(w io.Writer, r *http.Request) error) http.HandlerFunc {
return func(w http.ResponseWriter, r *http.Request) {
if r.FormValue("raw") != "" {
w.Header().Set("Content-Type", "application/octet-stream")
if err := prof(w, r); err != nil {
w.Header().Set("Content-Type", "text/plain; charset=utf-8")
w.Header().Set("X-Go-Pprof", "1")
http.Error(w, fmt.Sprintf("failed to get profile: %v", err), http.StatusInternalServerError)
return
}
return
}
blockf, err := os.CreateTemp("", "block")
if err != nil {
http.Error(w, fmt.Sprintf("failed to create temp file: %v", err), http.StatusInternalServerError)
return
}
defer func() {
blockf.Close()
os.Remove(blockf.Name())
}()
blockb := bufio.NewWriter(blockf)
if err := prof(blockb, r); err != nil {
http.Error(w, fmt.Sprintf("failed to generate profile: %v", err), http.StatusInternalServerError)
return
}
if err := blockb.Flush(); err != nil {
http.Error(w, fmt.Sprintf("failed to flush temp file: %v", err), http.StatusInternalServerError)
return
}
if err := blockf.Close(); err != nil {
http.Error(w, fmt.Sprintf("failed to close temp file: %v", err), http.StatusInternalServerError)
return
}
svgFilename := blockf.Name() + ".svg"
if output, err := exec.Command(goCmd(), "tool", "pprof", "-svg", "-output", svgFilename, blockf.Name()).CombinedOutput(); err != nil {
http.Error(w, fmt.Sprintf("failed to execute go tool pprof: %v\n%s", err, output), http.StatusInternalServerError)
return
}
defer os.Remove(svgFilename)
w.Header().Set("Content-Type", "image/svg+xml")
http.ServeFile(w, r, svgFilename)
}
}
func buildProfile(prof map[uint64]Record) *profile.Profile {
p := &profile.Profile{
PeriodType: &profile.ValueType{Type: "trace", Unit: "count"},
Period: 1,
SampleType: []*profile.ValueType{
{Type: "contentions", Unit: "count"},
{Type: "delay", Unit: "nanoseconds"},
},
}
locs := make(map[uint64]*profile.Location)
funcs := make(map[string]*profile.Function)
for _, rec := range prof {
var sloc []*profile.Location
for _, frame := range rec.stk {
loc := locs[frame.PC]
if loc == nil {
fn := funcs[frame.File+frame.Fn]
if fn == nil {
fn = &profile.Function{
ID: uint64(len(p.Function) + 1),
Name: frame.Fn,
SystemName: frame.Fn,
Filename: frame.File,
}
p.Function = append(p.Function, fn)
funcs[frame.File+frame.Fn] = fn
}
loc = &profile.Location{
ID: uint64(len(p.Location) + 1),
Address: frame.PC,
Line: []profile.Line{
{
Function: fn,
Line: int64(frame.Line),
},
},
}
p.Location = append(p.Location, loc)
locs[frame.PC] = loc
}
sloc = append(sloc, loc)
}
p.Sample = append(p.Sample, &profile.Sample{
Value: []int64{int64(rec.n), rec.time},
Location: sloc,
})
}
return p
}