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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.
package trace
import (
"bufio"
"bytes"
"fmt"
"io"
"math/rand"
"os"
"os/exec"
"path/filepath"
"runtime"
"strconv"
"strings"
_ "unsafe"
)
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"
}
// Event describes one event in the trace.
type Event struct {
Off int // offset in input file (for debugging and error reporting)
Type byte // one of Ev*
seq int64 // sequence number
Ts int64 // timestamp in nanoseconds
P int // P on which the event happened (can be one of TimerP, NetpollP, SyscallP)
G uint64 // G on which the event happened
StkID uint64 // unique stack ID
Stk []*Frame // stack trace (can be empty)
Args [3]uint64 // event-type-specific arguments
SArgs []string // event-type-specific string args
// linked event (can be nil), depends on event type:
// for GCStart: the GCStop
// for GCSTWStart: the GCSTWDone
// for GCSweepStart: the GCSweepDone
// for GoCreate: first GoStart of the created goroutine
// for GoStart/GoStartLabel: the associated GoEnd, GoBlock or other blocking event
// for GoSched/GoPreempt: the next GoStart
// for GoBlock and other blocking events: the unblock event
// for GoUnblock: the associated GoStart
// for blocking GoSysCall: the associated GoSysExit
// for GoSysExit: the next GoStart
// for GCMarkAssistStart: the associated GCMarkAssistDone
// for UserTaskCreate: the UserTaskEnd
// for UserRegion: if the start region, the corresponding UserRegion end event
Link *Event
}
// Frame is a frame in stack traces.
type Frame struct {
PC uint64
Fn string
File string
Line int
}
const (
// Special P identifiers:
FakeP = 1000000 + iota
TimerP // depicts timer unblocks
NetpollP // depicts network unblocks
SyscallP // depicts returns from syscalls
GCP // depicts GC state
ProfileP // depicts recording of CPU profile samples
)
// ParseResult is the result of Parse.
type ParseResult struct {
// Events is the sorted list of Events in the trace.
Events []*Event
// Stacks is the stack traces keyed by stack IDs from the trace.
Stacks map[uint64][]*Frame
}
// Parse parses, post-processes and verifies the trace.
func Parse(r io.Reader, bin string) (ParseResult, error) {
ver, res, err := parse(r, bin)
if err != nil {
return ParseResult{}, err
}
if ver < 1007 && bin == "" {
return ParseResult{}, fmt.Errorf("for traces produced by go 1.6 or below, the binary argument must be provided")
}
return res, nil
}
// parse parses, post-processes and verifies the trace. It returns the
// trace version and the list of events.
func parse(r io.Reader, bin string) (int, ParseResult, error) {
ver, rawEvents, strings, err := readTrace(r)
if err != nil {
return 0, ParseResult{}, err
}
events, stacks, err := parseEvents(ver, rawEvents, strings)
if err != nil {
return 0, ParseResult{}, err
}
events = removeFutile(events)
err = postProcessTrace(ver, events)
if err != nil {
return 0, ParseResult{}, err
}
// Attach stack traces.
for _, ev := range events {
if ev.StkID != 0 {
ev.Stk = stacks[ev.StkID]
}
}
if ver < 1007 && bin != "" {
if err := symbolize(events, bin); err != nil {
return 0, ParseResult{}, err
}
}
return ver, ParseResult{Events: events, Stacks: stacks}, nil
}
// rawEvent is a helper type used during parsing.
type rawEvent struct {
off int
typ byte
args []uint64
sargs []string
}
// readTrace does wire-format parsing and verification.
// It does not care about specific event types and argument meaning.
func readTrace(r io.Reader) (ver int, events []rawEvent, strings map[uint64]string, err error) {
// Read and validate trace header.
var buf [16]byte
off, err := io.ReadFull(r, buf[:])
if err != nil {
err = fmt.Errorf("failed to read header: read %v, err %v", off, err)
return
}
ver, err = parseHeader(buf[:])
if err != nil {
return
}
switch ver {
case 1005, 1007, 1008, 1009, 1010, 1011, 1019:
// Note: When adding a new version, confirm that canned traces from the
// old version are part of the test suite. Add them using mkcanned.bash.
break
default:
err = fmt.Errorf("unsupported trace file version %v.%v (update Go toolchain) %v", ver/1000, ver%1000, ver)
return
}
// Read events.
strings = make(map[uint64]string)
for {
// Read event type and number of arguments (1 byte).
off0 := off
var n int
n, err = r.Read(buf[:1])
if err == io.EOF {
err = nil
break
}
if err != nil || n != 1 {
err = fmt.Errorf("failed to read trace at offset 0x%x: n=%v err=%v", off0, n, err)
return
}
off += n
typ := buf[0] << 2 >> 2
narg := buf[0]>>6 + 1
inlineArgs := byte(4)
if ver < 1007 {
narg++
inlineArgs++
}
if typ == EvNone || typ >= EvCount || EventDescriptions[typ].minVersion > ver {
err = fmt.Errorf("unknown event type %v at offset 0x%x", typ, off0)
return
}
if typ == EvString {
// String dictionary entry [ID, length, string].
var id uint64
id, off, err = readVal(r, off)
if err != nil {
return
}
if id == 0 {
err = fmt.Errorf("string at offset %d has invalid id 0", off)
return
}
if strings[id] != "" {
err = fmt.Errorf("string at offset %d has duplicate id %v", off, id)
return
}
var ln uint64
ln, off, err = readVal(r, off)
if err != nil {
return
}
if ln == 0 {
err = fmt.Errorf("string at offset %d has invalid length 0", off)
return
}
if ln > 1e6 {
err = fmt.Errorf("string at offset %d has too large length %v", off, ln)
return
}
buf := make([]byte, ln)
var n int
n, err = io.ReadFull(r, buf)
if err != nil {
err = fmt.Errorf("failed to read trace at offset %d: read %v, want %v, error %v", off, n, ln, err)
return
}
off += n
strings[id] = string(buf)
continue
}
ev := rawEvent{typ: typ, off: off0}
if narg < inlineArgs {
for i := 0; i < int(narg); i++ {
var v uint64
v, off, err = readVal(r, off)
if err != nil {
err = fmt.Errorf("failed to read event %v argument at offset %v (%v)", typ, off, err)
return
}
ev.args = append(ev.args, v)
}
} else {
// More than inlineArgs args, the first value is length of the event in bytes.
var v uint64
v, off, err = readVal(r, off)
if err != nil {
err = fmt.Errorf("failed to read event %v argument at offset %v (%v)", typ, off, err)
return
}
evLen := v
off1 := off
for evLen > uint64(off-off1) {
v, off, err = readVal(r, off)
if err != nil {
err = fmt.Errorf("failed to read event %v argument at offset %v (%v)", typ, off, err)
return
}
ev.args = append(ev.args, v)
}
if evLen != uint64(off-off1) {
err = fmt.Errorf("event has wrong length at offset 0x%x: want %v, got %v", off0, evLen, off-off1)
return
}
}
switch ev.typ {
case EvUserLog: // EvUserLog records are followed by a value string of length ev.args[len(ev.args)-1]
var s string
s, off, err = readStr(r, off)
ev.sargs = append(ev.sargs, s)
}
events = append(events, ev)
}
return
}
func readStr(r io.Reader, off0 int) (s string, off int, err error) {
var sz uint64
sz, off, err = readVal(r, off0)
if err != nil || sz == 0 {
return "", off, err
}
if sz > 1e6 {
return "", off, fmt.Errorf("string at offset %d is too large (len=%d)", off, sz)
}
buf := make([]byte, sz)
n, err := io.ReadFull(r, buf)
if err != nil || sz != uint64(n) {
return "", off + n, fmt.Errorf("failed to read trace at offset %d: read %v, want %v, error %v", off, n, sz, err)
}
return string(buf), off + n, nil
}
// parseHeader parses trace header of the form "go 1.7 trace\x00\x00\x00\x00"
// and returns parsed version as 1007.
func parseHeader(buf []byte) (int, error) {
if len(buf) != 16 {
return 0, fmt.Errorf("bad header length")
}
if buf[0] != 'g' || buf[1] != 'o' || buf[2] != ' ' ||
buf[3] < '1' || buf[3] > '9' ||
buf[4] != '.' ||
buf[5] < '1' || buf[5] > '9' {
return 0, fmt.Errorf("not a trace file")
}
ver := int(buf[5] - '0')
i := 0
for ; buf[6+i] >= '0' && buf[6+i] <= '9' && i < 2; i++ {
ver = ver*10 + int(buf[6+i]-'0')
}
ver += int(buf[3]-'0') * 1000
if !bytes.Equal(buf[6+i:], []byte(" trace\x00\x00\x00\x00")[:10-i]) {
return 0, fmt.Errorf("not a trace file")
}
return ver, nil
}
// Parse events transforms raw events into events.
// It does analyze and verify per-event-type arguments.
func parseEvents(ver int, rawEvents []rawEvent, strings map[uint64]string) (events []*Event, stacks map[uint64][]*Frame, err error) {
var ticksPerSec, lastSeq, lastTs int64
var lastG uint64
var lastP int
timerGoids := make(map[uint64]bool)
lastGs := make(map[int]uint64) // last goroutine running on P
stacks = make(map[uint64][]*Frame)
batches := make(map[int][]*Event) // events by P
for _, raw := range rawEvents {
desc := EventDescriptions[raw.typ]
if desc.Name == "" {
err = fmt.Errorf("missing description for event type %v", raw.typ)
return
}
narg := argNum(raw, ver)
if len(raw.args) != narg {
err = fmt.Errorf("%v has wrong number of arguments at offset 0x%x: want %v, got %v",
desc.Name, raw.off, narg, len(raw.args))
return
}
switch raw.typ {
case EvBatch:
lastGs[lastP] = lastG
lastP = int(raw.args[0])
lastG = lastGs[lastP]
if ver < 1007 {
lastSeq = int64(raw.args[1])
lastTs = int64(raw.args[2])
} else {
lastTs = int64(raw.args[1])
}
case EvFrequency:
ticksPerSec = int64(raw.args[0])
if ticksPerSec <= 0 {
// The most likely cause for this is tick skew on different CPUs.
// For example, solaris/amd64 seems to have wildly different
// ticks on different CPUs.
err = ErrTimeOrder
return
}
case EvTimerGoroutine:
timerGoids[raw.args[0]] = true
case EvStack:
if len(raw.args) < 2 {
err = fmt.Errorf("EvStack has wrong number of arguments at offset 0x%x: want at least 2, got %v",
raw.off, len(raw.args))
return
}
size := raw.args[1]
if size > 1000 {
err = fmt.Errorf("EvStack has bad number of frames at offset 0x%x: %v",
raw.off, size)
return
}
want := 2 + 4*size
if ver < 1007 {
want = 2 + size
}
if uint64(len(raw.args)) != want {
err = fmt.Errorf("EvStack has wrong number of arguments at offset 0x%x: want %v, got %v",
raw.off, want, len(raw.args))
return
}
id := raw.args[0]
if id != 0 && size > 0 {
stk := make([]*Frame, size)
for i := 0; i < int(size); i++ {
if ver < 1007 {
stk[i] = &Frame{PC: raw.args[2+i]}
} else {
pc := raw.args[2+i*4+0]
fn := raw.args[2+i*4+1]
file := raw.args[2+i*4+2]
line := raw.args[2+i*4+3]
stk[i] = &Frame{PC: pc, Fn: strings[fn], File: strings[file], Line: int(line)}
}
}
stacks[id] = stk
}
default:
e := &Event{Off: raw.off, Type: raw.typ, P: lastP, G: lastG}
var argOffset int
if ver < 1007 {
e.seq = lastSeq + int64(raw.args[0])
e.Ts = lastTs + int64(raw.args[1])
lastSeq = e.seq
argOffset = 2
} else {
e.Ts = lastTs + int64(raw.args[0])
argOffset = 1
}
lastTs = e.Ts
for i := argOffset; i < narg; i++ {
if i == narg-1 && desc.Stack {
e.StkID = raw.args[i]
} else {
e.Args[i-argOffset] = raw.args[i]
}
}
switch raw.typ {
case EvGoStart, EvGoStartLocal, EvGoStartLabel:
lastG = e.Args[0]
e.G = lastG
if raw.typ == EvGoStartLabel {
e.SArgs = []string{strings[e.Args[2]]}
}
case EvGCSTWStart:
e.G = 0
switch e.Args[0] {
case 0:
e.SArgs = []string{"mark termination"}
case 1:
e.SArgs = []string{"sweep termination"}
default:
err = fmt.Errorf("unknown STW kind %d", e.Args[0])
return
}
case EvGCStart, EvGCDone, EvGCSTWDone:
e.G = 0
case EvGoEnd, EvGoStop, EvGoSched, EvGoPreempt,
EvGoSleep, EvGoBlock, EvGoBlockSend, EvGoBlockRecv,
EvGoBlockSelect, EvGoBlockSync, EvGoBlockCond, EvGoBlockNet,
EvGoSysBlock, EvGoBlockGC:
lastG = 0
case EvGoSysExit, EvGoWaiting, EvGoInSyscall:
e.G = e.Args[0]
case EvUserTaskCreate:
// e.Args 0: taskID, 1:parentID, 2:nameID
e.SArgs = []string{strings[e.Args[2]]}
case EvUserRegion:
// e.Args 0: taskID, 1: mode, 2:nameID
e.SArgs = []string{strings[e.Args[2]]}
case EvUserLog:
// e.Args 0: taskID, 1:keyID, 2: stackID
e.SArgs = []string{strings[e.Args[1]], raw.sargs[0]}
case EvCPUSample:
e.Ts = int64(e.Args[0])
e.P = int(e.Args[1])
e.G = e.Args[2]
e.Args[0] = 0
}
switch raw.typ {
default:
batches[lastP] = append(batches[lastP], e)
case EvCPUSample:
// Most events are written out by the active P at the exact
// moment they describe. CPU profile samples are different
// because they're written to the tracing log after some delay,
// by a separate worker goroutine, into a separate buffer.
//
// We keep these in their own batch until all of the batches are
// merged in timestamp order. We also (right before the merge)
// re-sort these events by the timestamp captured in the
// profiling signal handler.
batches[ProfileP] = append(batches[ProfileP], e)
}
}
}
if len(batches) == 0 {
err = fmt.Errorf("trace is empty")
return
}
if ticksPerSec == 0 {
err = fmt.Errorf("no EvFrequency event")
return
}
if BreakTimestampsForTesting {
var batchArr [][]*Event
for _, batch := range batches {
batchArr = append(batchArr, batch)
}
for i := 0; i < 5; i++ {
batch := batchArr[rand.Intn(len(batchArr))]
batch[rand.Intn(len(batch))].Ts += int64(rand.Intn(2000) - 1000)
}
}
if ver < 1007 {
events, err = order1005(batches)
} else {
events, err = order1007(batches)
}
if err != nil {
return
}
// Translate cpu ticks to real time.
minTs := events[0].Ts
// Use floating point to avoid integer overflows.
freq := 1e9 / float64(ticksPerSec)
for _, ev := range events {
ev.Ts = int64(float64(ev.Ts-minTs) * freq)
// Move timers and syscalls to separate fake Ps.
if timerGoids[ev.G] && ev.Type == EvGoUnblock {
ev.P = TimerP
}
if ev.Type == EvGoSysExit {
ev.P = SyscallP
}
}
return
}
// removeFutile removes all constituents of futile wakeups (block, unblock, start).
// For example, a goroutine was unblocked on a mutex, but another goroutine got
// ahead and acquired the mutex before the first goroutine is scheduled,
// so the first goroutine has to block again. Such wakeups happen on buffered
// channels and sync.Mutex, but are generally not interesting for end user.
func removeFutile(events []*Event) []*Event {
// Two non-trivial aspects:
// 1. A goroutine can be preempted during a futile wakeup and migrate to another P.
// We want to remove all of that.
// 2. Tracing can start in the middle of a futile wakeup.
// That is, we can see a futile wakeup event w/o the actual wakeup before it.
// postProcessTrace runs after us and ensures that we leave the trace in a consistent state.
// Phase 1: determine futile wakeup sequences.
type G struct {
futile bool
wakeup []*Event // wakeup sequence (subject for removal)
}
gs := make(map[uint64]G)
futile := make(map[*Event]bool)
for _, ev := range events {
switch ev.Type {
case EvGoUnblock:
g := gs[ev.Args[0]]
g.wakeup = []*Event{ev}
gs[ev.Args[0]] = g
case EvGoStart, EvGoPreempt, EvFutileWakeup:
g := gs[ev.G]
g.wakeup = append(g.wakeup, ev)
if ev.Type == EvFutileWakeup {
g.futile = true
}
gs[ev.G] = g
case EvGoBlock, EvGoBlockSend, EvGoBlockRecv, EvGoBlockSelect, EvGoBlockSync, EvGoBlockCond:
g := gs[ev.G]
if g.futile {
futile[ev] = true
for _, ev1 := range g.wakeup {
futile[ev1] = true
}
}
delete(gs, ev.G)
}
}
// Phase 2: remove futile wakeup sequences.
newEvents := events[:0] // overwrite the original slice
for _, ev := range events {
if !futile[ev] {
newEvents = append(newEvents, ev)
}
}
return newEvents
}
// ErrTimeOrder is returned by Parse when the trace contains
// time stamps that do not respect actual event ordering.
var ErrTimeOrder = fmt.Errorf("time stamps out of order")
// postProcessTrace does inter-event verification and information restoration.
// The resulting trace is guaranteed to be consistent
// (for example, a P does not run two Gs at the same time, or a G is indeed
// blocked before an unblock event).
func postProcessTrace(ver int, events []*Event) error {
const (
gDead = iota
gRunnable
gRunning
gWaiting
)
type gdesc struct {
state int
ev *Event
evStart *Event
evCreate *Event
evMarkAssist *Event
}
type pdesc struct {
running bool
g uint64
evSTW *Event
evSweep *Event
}
gs := make(map[uint64]gdesc)
ps := make(map[int]pdesc)
tasks := make(map[uint64]*Event) // task id to task creation events
activeRegions := make(map[uint64][]*Event) // goroutine id to stack of regions
gs[0] = gdesc{state: gRunning}
var evGC, evSTW *Event
checkRunning := func(p pdesc, g gdesc, ev *Event, allowG0 bool) error {
name := EventDescriptions[ev.Type].Name
if g.state != gRunning {
return fmt.Errorf("g %v is not running while %v (offset %v, time %v)", ev.G, name, ev.Off, ev.Ts)
}
if p.g != ev.G {
return fmt.Errorf("p %v is not running g %v while %v (offset %v, time %v)", ev.P, ev.G, name, ev.Off, ev.Ts)
}
if !allowG0 && ev.G == 0 {
return fmt.Errorf("g 0 did %v (offset %v, time %v)", EventDescriptions[ev.Type].Name, ev.Off, ev.Ts)
}
return nil
}
for _, ev := range events {
g := gs[ev.G]
p := ps[ev.P]
switch ev.Type {
case EvProcStart:
if p.running {
return fmt.Errorf("p %v is running before start (offset %v, time %v)", ev.P, ev.Off, ev.Ts)
}
p.running = true
case EvProcStop:
if !p.running {
return fmt.Errorf("p %v is not running before stop (offset %v, time %v)", ev.P, ev.Off, ev.Ts)
}
if p.g != 0 {
return fmt.Errorf("p %v is running a goroutine %v during stop (offset %v, time %v)", ev.P, p.g, ev.Off, ev.Ts)
}
p.running = false
case EvGCStart:
if evGC != nil {
return fmt.Errorf("previous GC is not ended before a new one (offset %v, time %v)", ev.Off, ev.Ts)
}
evGC = ev
// Attribute this to the global GC state.
ev.P = GCP
case EvGCDone:
if evGC == nil {
return fmt.Errorf("bogus GC end (offset %v, time %v)", ev.Off, ev.Ts)
}
evGC.Link = ev
evGC = nil
case EvGCSTWStart:
evp := &evSTW
if ver < 1010 {
// Before 1.10, EvGCSTWStart was per-P.
evp = &p.evSTW
}
if *evp != nil {
return fmt.Errorf("previous STW is not ended before a new one (offset %v, time %v)", ev.Off, ev.Ts)
}
*evp = ev
case EvGCSTWDone:
evp := &evSTW
if ver < 1010 {
// Before 1.10, EvGCSTWDone was per-P.
evp = &p.evSTW
}
if *evp == nil {
return fmt.Errorf("bogus STW end (offset %v, time %v)", ev.Off, ev.Ts)
}
(*evp).Link = ev
*evp = nil
case EvGCSweepStart:
if p.evSweep != nil {
return fmt.Errorf("previous sweeping is not ended before a new one (offset %v, time %v)", ev.Off, ev.Ts)
}
p.evSweep = ev
case EvGCMarkAssistStart:
if g.evMarkAssist != nil {
return fmt.Errorf("previous mark assist is not ended before a new one (offset %v, time %v)", ev.Off, ev.Ts)
}
g.evMarkAssist = ev
case EvGCMarkAssistDone:
// Unlike most events, mark assists can be in progress when a
// goroutine starts tracing, so we can't report an error here.
if g.evMarkAssist != nil {
g.evMarkAssist.Link = ev
g.evMarkAssist = nil
}
case EvGCSweepDone:
if p.evSweep == nil {
return fmt.Errorf("bogus sweeping end (offset %v, time %v)", ev.Off, ev.Ts)
}
p.evSweep.Link = ev
p.evSweep = nil
case EvGoWaiting:
if g.state != gRunnable {
return fmt.Errorf("g %v is not runnable before EvGoWaiting (offset %v, time %v)", ev.G, ev.Off, ev.Ts)
}
g.state = gWaiting
g.ev = ev
case EvGoInSyscall:
if g.state != gRunnable {
return fmt.Errorf("g %v is not runnable before EvGoInSyscall (offset %v, time %v)", ev.G, ev.Off, ev.Ts)
}
g.state = gWaiting
g.ev = ev
case EvGoCreate:
if err := checkRunning(p, g, ev, true); err != nil {
return err
}
if _, ok := gs[ev.Args[0]]; ok {
return fmt.Errorf("g %v already exists (offset %v, time %v)", ev.Args[0], ev.Off, ev.Ts)
}
gs[ev.Args[0]] = gdesc{state: gRunnable, ev: ev, evCreate: ev}
case EvGoStart, EvGoStartLabel:
if g.state != gRunnable {
return fmt.Errorf("g %v is not runnable before start (offset %v, time %v)", ev.G, ev.Off, ev.Ts)
}
if p.g != 0 {
return fmt.Errorf("p %v is already running g %v while start g %v (offset %v, time %v)", ev.P, p.g, ev.G, ev.Off, ev.Ts)
}
g.state = gRunning
g.evStart = ev
p.g = ev.G
if g.evCreate != nil {
if ver < 1007 {
// +1 because symbolizer expects return pc.
ev.Stk = []*Frame{{PC: g.evCreate.Args[1] + 1}}
} else {
ev.StkID = g.evCreate.Args[1]
}
g.evCreate = nil
}
if g.ev != nil {
g.ev.Link = ev
g.ev = nil
}
case EvGoEnd, EvGoStop:
if err := checkRunning(p, g, ev, false); err != nil {
return err
}
g.evStart.Link = ev
g.evStart = nil
g.state = gDead
p.g = 0
if ev.Type == EvGoEnd { // flush all active regions
regions := activeRegions[ev.G]
for _, s := range regions {
s.Link = ev
}
delete(activeRegions, ev.G)
}
case EvGoSched, EvGoPreempt:
if err := checkRunning(p, g, ev, false); err != nil {
return err
}
g.state = gRunnable
g.evStart.Link = ev
g.evStart = nil
p.g = 0
g.ev = ev
case EvGoUnblock:
if g.state != gRunning {
return fmt.Errorf("g %v is not running while unpark (offset %v, time %v)", ev.G, ev.Off, ev.Ts)
}
if ev.P != TimerP && p.g != ev.G {
return fmt.Errorf("p %v is not running g %v while unpark (offset %v, time %v)", ev.P, ev.G, ev.Off, ev.Ts)
}
g1 := gs[ev.Args[0]]
if g1.state != gWaiting {
return fmt.Errorf("g %v is not waiting before unpark (offset %v, time %v)", ev.Args[0], ev.Off, ev.Ts)
}
if g1.ev != nil && g1.ev.Type == EvGoBlockNet && ev.P != TimerP {
ev.P = NetpollP
}
if g1.ev != nil {
g1.ev.Link = ev
}
g1.state = gRunnable
g1.ev = ev
gs[ev.Args[0]] = g1
case EvGoSysCall:
if err := checkRunning(p, g, ev, false); err != nil {
return err
}
g.ev = ev
case EvGoSysBlock:
if err := checkRunning(p, g, ev, false); err != nil {
return err
}
g.state = gWaiting
g.evStart.Link = ev
g.evStart = nil
p.g = 0
case EvGoSysExit:
if g.state != gWaiting {
return fmt.Errorf("g %v is not waiting during syscall exit (offset %v, time %v)", ev.G, ev.Off, ev.Ts)
}
if g.ev != nil && g.ev.Type == EvGoSysCall {
g.ev.Link = ev
}
g.state = gRunnable
g.ev = ev
case EvGoSleep, EvGoBlock, EvGoBlockSend, EvGoBlockRecv,
EvGoBlockSelect, EvGoBlockSync, EvGoBlockCond, EvGoBlockNet, EvGoBlockGC:
if err := checkRunning(p, g, ev, false); err != nil {
return err
}
g.state = gWaiting
g.ev = ev
g.evStart.Link = ev
g.evStart = nil
p.g = 0
case EvUserTaskCreate:
taskid := ev.Args[0]
if prevEv, ok := tasks[taskid]; ok {
return fmt.Errorf("task id conflicts (id:%d), %q vs %q", taskid, ev, prevEv)
}
tasks[ev.Args[0]] = ev
case EvUserTaskEnd:
taskid := ev.Args[0]
if taskCreateEv, ok := tasks[taskid]; ok {
taskCreateEv.Link = ev
delete(tasks, taskid)
}
case EvUserRegion:
mode := ev.Args[1]
regions := activeRegions[ev.G]
if mode == 0 { // region start
activeRegions[ev.G] = append(regions, ev) // push
} else if mode == 1 { // region end
n := len(regions)
if n > 0 { // matching region start event is in the trace.
s := regions[n-1]
if s.Args[0] != ev.Args[0] || s.SArgs[0] != ev.SArgs[0] { // task id, region name mismatch
return fmt.Errorf("misuse of region in goroutine %d: span end %q when the inner-most active span start event is %q", ev.G, ev, s)
}
// Link region start event with span end event
s.Link = ev
if n > 1 {
activeRegions[ev.G] = regions[:n-1]
} else {
delete(activeRegions, ev.G)
}
}
} else {
return fmt.Errorf("invalid user region mode: %q", ev)
}
}
gs[ev.G] = g
ps[ev.P] = p
}
// TODO(dvyukov): restore stacks for EvGoStart events.
// TODO(dvyukov): test that all EvGoStart events has non-nil Link.
return nil
}
// symbolize attaches func/file/line info to stack traces.
func symbolize(events []*Event, bin string) error {
// First, collect and dedup all pcs.
pcs := make(map[uint64]*Frame)
for _, ev := range events {
for _, f := range ev.Stk {
pcs[f.PC] = nil
}
}
// Start addr2line.
cmd := exec.Command(goCmd(), "tool", "addr2line", bin)
in, err := cmd.StdinPipe()
if err != nil {
return fmt.Errorf("failed to pipe addr2line stdin: %v", err)
}
cmd.Stderr = os.Stderr
out, err := cmd.StdoutPipe()
if err != nil {
return fmt.Errorf("failed to pipe addr2line stdout: %v", err)
}
err = cmd.Start()
if err != nil {
return fmt.Errorf("failed to start addr2line: %v", err)
}
outb := bufio.NewReader(out)
// Write all pcs to addr2line.
// Need to copy pcs to an array, because map iteration order is non-deterministic.
var pcArray []uint64
for pc := range pcs {
pcArray = append(pcArray, pc)
_, err := fmt.Fprintf(in, "0x%x\n", pc-1)
if err != nil {
return fmt.Errorf("failed to write to addr2line: %v", err)
}
}
in.Close()
// Read in answers.
for _, pc := range pcArray {
fn, err := outb.ReadString('\n')
if err != nil {
return fmt.Errorf("failed to read from addr2line: %v", err)
}
file, err := outb.ReadString('\n')
if err != nil {
return fmt.Errorf("failed to read from addr2line: %v", err)
}
f := &Frame{PC: pc}
f.Fn = fn[:len(fn)-1]
f.File = file[:len(file)-1]
if colon := strings.LastIndex(f.File, ":"); colon != -1 {
ln, err := strconv.Atoi(f.File[colon+1:])
if err == nil {
f.File = f.File[:colon]
f.Line = ln
}
}
pcs[pc] = f
}
cmd.Wait()
// Replace frames in events array.
for _, ev := range events {
for i, f := range ev.Stk {
ev.Stk[i] = pcs[f.PC]
}
}
return nil
}
// readVal reads unsigned base-128 value from r.
func readVal(r io.Reader, off0 int) (v uint64, off int, err error) {
off = off0
for i := 0; i < 10; i++ {
var buf [1]byte
var n int
n, err = r.Read(buf[:])
if err != nil || n != 1 {
return 0, 0, fmt.Errorf("failed to read trace at offset %d: read %v, error %v", off0, n, err)
}
off++
v |= uint64(buf[0]&0x7f) << (uint(i) * 7)
if buf[0]&0x80 == 0 {
return
}
}
return 0, 0, fmt.Errorf("bad value at offset 0x%x", off0)
}
// Print dumps events to stdout. For debugging.
func Print(events []*Event) {
for _, ev := range events {
PrintEvent(ev)
}
}
// PrintEvent dumps the event to stdout. For debugging.
func PrintEvent(ev *Event) {
fmt.Printf("%s\n", ev)
}
func (ev *Event) String() string {
desc := EventDescriptions[ev.Type]
w := new(strings.Builder)
fmt.Fprintf(w, "%v %v p=%v g=%v off=%v", ev.Ts, desc.Name, ev.P, ev.G, ev.Off)
for i, a := range desc.Args {
fmt.Fprintf(w, " %v=%v", a, ev.Args[i])
}
for i, a := range desc.SArgs {
fmt.Fprintf(w, " %v=%v", a, ev.SArgs[i])
}
return w.String()
}
// argNum returns total number of args for the event accounting for timestamps,
// sequence numbers and differences between trace format versions.
func argNum(raw rawEvent, ver int) int {
desc := EventDescriptions[raw.typ]
if raw.typ == EvStack {
return len(raw.args)
}
narg := len(desc.Args)
if desc.Stack {
narg++
}
switch raw.typ {
case EvBatch, EvFrequency, EvTimerGoroutine:
if ver < 1007 {
narg++ // there was an unused arg before 1.7
}
return narg
}
narg++ // timestamp
if ver < 1007 {
narg++ // sequence
}
switch raw.typ {
case EvGCSweepDone:
if ver < 1009 {
narg -= 2 // 1.9 added two arguments
}
case EvGCStart, EvGoStart, EvGoUnblock:
if ver < 1007 {
narg-- // 1.7 added an additional seq arg
}
case EvGCSTWStart:
if ver < 1010 {
narg-- // 1.10 added an argument
}
}
return narg
}
// BreakTimestampsForTesting causes the parser to randomly alter timestamps (for testing of broken cputicks).
var BreakTimestampsForTesting bool
// Event types in the trace.
// Verbatim copy from src/runtime/trace.go with the "trace" prefix removed.
const (
EvNone = 0 // unused
EvBatch = 1 // start of per-P batch of events [pid, timestamp]
EvFrequency = 2 // contains tracer timer frequency [frequency (ticks per second)]
EvStack = 3 // stack [stack id, number of PCs, array of {PC, func string ID, file string ID, line}]
EvGomaxprocs = 4 // current value of GOMAXPROCS [timestamp, GOMAXPROCS, stack id]
EvProcStart = 5 // start of P [timestamp, thread id]
EvProcStop = 6 // stop of P [timestamp]
EvGCStart = 7 // GC start [timestamp, seq, stack id]
EvGCDone = 8 // GC done [timestamp]
EvGCSTWStart = 9 // GC mark termination start [timestamp, kind]
EvGCSTWDone = 10 // GC mark termination done [timestamp]
EvGCSweepStart = 11 // GC sweep start [timestamp, stack id]
EvGCSweepDone = 12 // GC sweep done [timestamp, swept, reclaimed]
EvGoCreate = 13 // goroutine creation [timestamp, new goroutine id, new stack id, stack id]
EvGoStart = 14 // goroutine starts running [timestamp, goroutine id, seq]
EvGoEnd = 15 // goroutine ends [timestamp]
EvGoStop = 16 // goroutine stops (like in select{}) [timestamp, stack]
EvGoSched = 17 // goroutine calls Gosched [timestamp, stack]
EvGoPreempt = 18 // goroutine is preempted [timestamp, stack]
EvGoSleep = 19 // goroutine calls Sleep [timestamp, stack]
EvGoBlock = 20 // goroutine blocks [timestamp, stack]
EvGoUnblock = 21 // goroutine is unblocked [timestamp, goroutine id, seq, stack]
EvGoBlockSend = 22 // goroutine blocks on chan send [timestamp, stack]
EvGoBlockRecv = 23 // goroutine blocks on chan recv [timestamp, stack]
EvGoBlockSelect = 24 // goroutine blocks on select [timestamp, stack]
EvGoBlockSync = 25 // goroutine blocks on Mutex/RWMutex [timestamp, stack]
EvGoBlockCond = 26 // goroutine blocks on Cond [timestamp, stack]
EvGoBlockNet = 27 // goroutine blocks on network [timestamp, stack]
EvGoSysCall = 28 // syscall enter [timestamp, stack]
EvGoSysExit = 29 // syscall exit [timestamp, goroutine id, seq, real timestamp]
EvGoSysBlock = 30 // syscall blocks [timestamp]
EvGoWaiting = 31 // denotes that goroutine is blocked when tracing starts [timestamp, goroutine id]
EvGoInSyscall = 32 // denotes that goroutine is in syscall when tracing starts [timestamp, goroutine id]
EvHeapAlloc = 33 // gcController.heapLive change [timestamp, heap live bytes]
EvHeapGoal = 34 // gcController.heapGoal change [timestamp, heap goal bytes]
EvTimerGoroutine = 35 // denotes timer goroutine [timer goroutine id]
EvFutileWakeup = 36 // denotes that the previous wakeup of this goroutine was futile [timestamp]
EvString = 37 // string dictionary entry [ID, length, string]
EvGoStartLocal = 38 // goroutine starts running on the same P as the last event [timestamp, goroutine id]
EvGoUnblockLocal = 39 // goroutine is unblocked on the same P as the last event [timestamp, goroutine id, stack]
EvGoSysExitLocal = 40 // syscall exit on the same P as the last event [timestamp, goroutine id, real timestamp]
EvGoStartLabel = 41 // goroutine starts running with label [timestamp, goroutine id, seq, label string id]
EvGoBlockGC = 42 // goroutine blocks on GC assist [timestamp, stack]
EvGCMarkAssistStart = 43 // GC mark assist start [timestamp, stack]
EvGCMarkAssistDone = 44 // GC mark assist done [timestamp]
EvUserTaskCreate = 45 // trace.NewContext [timestamp, internal task id, internal parent id, stack, name string]
EvUserTaskEnd = 46 // end of task [timestamp, internal task id, stack]
EvUserRegion = 47 // trace.WithRegion [timestamp, internal task id, mode(0:start, 1:end), stack, name string]
EvUserLog = 48 // trace.Log [timestamp, internal id, key string id, stack, value string]
EvCPUSample = 49 // CPU profiling sample [timestamp, real timestamp, real P id (-1 when absent), goroutine id, stack]
EvCount = 50
)
var EventDescriptions = [EvCount]struct {
Name string
minVersion int
Stack bool
Args []string
SArgs []string // string arguments
}{
EvNone: {"None", 1005, false, []string{}, nil},
EvBatch: {"Batch", 1005, false, []string{"p", "ticks"}, nil}, // in 1.5 format it was {"p", "seq", "ticks"}
EvFrequency: {"Frequency", 1005, false, []string{"freq"}, nil}, // in 1.5 format it was {"freq", "unused"}
EvStack: {"Stack", 1005, false, []string{"id", "siz"}, nil},
EvGomaxprocs: {"Gomaxprocs", 1005, true, []string{"procs"}, nil},
EvProcStart: {"ProcStart", 1005, false, []string{"thread"}, nil},
EvProcStop: {"ProcStop", 1005, false, []string{}, nil},
EvGCStart: {"GCStart", 1005, true, []string{"seq"}, nil}, // in 1.5 format it was {}
EvGCDone: {"GCDone", 1005, false, []string{}, nil},
EvGCSTWStart: {"GCSTWStart", 1005, false, []string{"kindid"}, []string{"kind"}}, // <= 1.9, args was {} (implicitly {0})
EvGCSTWDone: {"GCSTWDone", 1005, false, []string{}, nil},
EvGCSweepStart: {"GCSweepStart", 1005, true, []string{}, nil},
EvGCSweepDone: {"GCSweepDone", 1005, false, []string{"swept", "reclaimed"}, nil}, // before 1.9, format was {}
EvGoCreate: {"GoCreate", 1005, true, []string{"g", "stack"}, nil},
EvGoStart: {"GoStart", 1005, false, []string{"g", "seq"}, nil}, // in 1.5 format it was {"g"}
EvGoEnd: {"GoEnd", 1005, false, []string{}, nil},
EvGoStop: {"GoStop", 1005, true, []string{}, nil},
EvGoSched: {"GoSched", 1005, true, []string{}, nil},
EvGoPreempt: {"GoPreempt", 1005, true, []string{}, nil},
EvGoSleep: {"GoSleep", 1005, true, []string{}, nil},
EvGoBlock: {"GoBlock", 1005, true, []string{}, nil},
EvGoUnblock: {"GoUnblock", 1005, true, []string{"g", "seq"}, nil}, // in 1.5 format it was {"g"}
EvGoBlockSend: {"GoBlockSend", 1005, true, []string{}, nil},
EvGoBlockRecv: {"GoBlockRecv", 1005, true, []string{}, nil},
EvGoBlockSelect: {"GoBlockSelect", 1005, true, []string{}, nil},
EvGoBlockSync: {"GoBlockSync", 1005, true, []string{}, nil},
EvGoBlockCond: {"GoBlockCond", 1005, true, []string{}, nil},
EvGoBlockNet: {"GoBlockNet", 1005, true, []string{}, nil},
EvGoSysCall: {"GoSysCall", 1005, true, []string{}, nil},
EvGoSysExit: {"GoSysExit", 1005, false, []string{"g", "seq", "ts"}, nil},
EvGoSysBlock: {"GoSysBlock", 1005, false, []string{}, nil},
EvGoWaiting: {"GoWaiting", 1005, false, []string{"g"}, nil},
EvGoInSyscall: {"GoInSyscall", 1005, false, []string{"g"}, nil},
EvHeapAlloc: {"HeapAlloc", 1005, false, []string{"mem"}, nil},
EvHeapGoal: {"HeapGoal", 1005, false, []string{"mem"}, nil},
EvTimerGoroutine: {"TimerGoroutine", 1005, false, []string{"g"}, nil}, // in 1.5 format it was {"g", "unused"}
EvFutileWakeup: {"FutileWakeup", 1005, false, []string{}, nil},
EvString: {"String", 1007, false, []string{}, nil},
EvGoStartLocal: {"GoStartLocal", 1007, false, []string{"g"}, nil},
EvGoUnblockLocal: {"GoUnblockLocal", 1007, true, []string{"g"}, nil},
EvGoSysExitLocal: {"GoSysExitLocal", 1007, false, []string{"g", "ts"}, nil},
EvGoStartLabel: {"GoStartLabel", 1008, false, []string{"g", "seq", "labelid"}, []string{"label"}},
EvGoBlockGC: {"GoBlockGC", 1008, true, []string{}, nil},
EvGCMarkAssistStart: {"GCMarkAssistStart", 1009, true, []string{}, nil},
EvGCMarkAssistDone: {"GCMarkAssistDone", 1009, false, []string{}, nil},
EvUserTaskCreate: {"UserTaskCreate", 1011, true, []string{"taskid", "pid", "typeid"}, []string{"name"}},
EvUserTaskEnd: {"UserTaskEnd", 1011, true, []string{"taskid"}, nil},
EvUserRegion: {"UserRegion", 1011, true, []string{"taskid", "mode", "typeid"}, []string{"name"}},
EvUserLog: {"UserLog", 1011, true, []string{"id", "keyid"}, []string{"category", "message"}},
EvCPUSample: {"CPUSample", 1019, true, []string{"ts", "p", "g"}, nil},
}