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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"
"cmd/internal/pprof/profile"
"fmt"
"internal/trace"
"io"
"io/ioutil"
"net/http"
"os"
"os/exec"
)
func init() {
http.HandleFunc("/io", serveSVGProfile(pprofIO))
http.HandleFunc("/block", serveSVGProfile(pprofBlock))
http.HandleFunc("/syscall", serveSVGProfile(pprofSyscall))
http.HandleFunc("/sched", serveSVGProfile(pprofSched))
}
// Record represents one entry in pprof-like profiles.
type Record struct {
stk []*trace.Frame
n uint64
time int64
}
// pprofIO generates IO pprof-like profile (time spent in IO wait).
func pprofIO(w io.Writer) error {
events, err := parseEvents()
if err != nil {
return err
}
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
}
rec := prof[ev.StkID]
rec.stk = ev.Stk
rec.n++
rec.time += ev.Link.Ts - ev.Ts
prof[ev.StkID] = rec
}
return buildProfile(prof).Write(w)
}
// pprofBlock generates blocking pprof-like profile (time spent blocked on synchronization primitives).
func pprofBlock(w io.Writer) error {
events, err := parseEvents()
if err != nil {
return err
}
prof := make(map[uint64]Record)
for _, ev := range events {
switch ev.Type {
case trace.EvGoBlockSend, trace.EvGoBlockRecv, trace.EvGoBlockSelect,
trace.EvGoBlockSync, trace.EvGoBlockCond:
default:
continue
}
if ev.Link == nil || ev.StkID == 0 || len(ev.Stk) == 0 {
continue
}
rec := prof[ev.StkID]
rec.stk = ev.Stk
rec.n++
rec.time += ev.Link.Ts - ev.Ts
prof[ev.StkID] = rec
}
return buildProfile(prof).Write(w)
}
// pprofSyscall generates syscall pprof-like profile (time spent blocked in syscalls).
func pprofSyscall(w io.Writer) error {
events, err := parseEvents()
if err != nil {
return err
}
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
}
rec := prof[ev.StkID]
rec.stk = ev.Stk
rec.n++
rec.time += ev.Link.Ts - ev.Ts
prof[ev.StkID] = rec
}
return buildProfile(prof).Write(w)
}
// pprofSched generates scheduler latency pprof-like profile
// (time between a goroutine become runnable and actually scheduled for execution).
func pprofSched(w io.Writer) error {
events, err := parseEvents()
if err != nil {
return err
}
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
}
rec := prof[ev.StkID]
rec.stk = ev.Stk
rec.n++
rec.time += ev.Link.Ts - ev.Ts
prof[ev.StkID] = rec
}
return buildProfile(prof).Write(w)
}
// serveSVGProfile serves pprof-like profile generated by prof as svg.
func serveSVGProfile(prof func(w io.Writer) error) http.HandlerFunc {
return func(w http.ResponseWriter, r *http.Request) {
blockf, err := ioutil.TempFile("", "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); 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("go", "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{
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
}