lib/sync: Log everything...

This commit is contained in:
Audrius Butkevicius 2016-11-03 21:33:33 +00:00
parent e408f1061a
commit 3418497f3d
3 changed files with 99 additions and 43 deletions

View File

@ -12,8 +12,8 @@ import (
"time"
)
type Holder interface {
Holder() (string, int)
type Holdable interface {
Holders() string
}
func newDeadlockDetector(timeout time.Duration) *deadlockDetector {
@ -49,9 +49,8 @@ func (d *deadlockDetector) Watch(name string, mut sync.Locker) {
if r := <-ok; !r {
msg := fmt.Sprintf("deadlock detected at %s", name)
for otherName, otherMut := range d.lockers {
if otherHolder, ok := otherMut.(Holder); ok {
holder, goid := otherHolder.Holder()
msg += fmt.Sprintf("\n %s = current holder: %s at routine %d", otherName, holder, goid)
if otherHolder, ok := otherMut.(Holdable); ok {
msg += "\n===" + otherName + "===\n" + otherHolder.Holders()
}
}
panic(msg)

View File

@ -36,16 +36,21 @@ type WaitGroup interface {
func NewMutex() Mutex {
if debug {
return &loggedMutex{}
mutex := &loggedMutex{}
mutex.holder.Store(holder{})
return mutex
}
return &sync.Mutex{}
}
func NewRWMutex() RWMutex {
if debug {
return &loggedRWMutex{
unlockers: make([]string, 0),
mutex := &loggedRWMutex{
readHolders: make(map[int][]holder),
unlockers: make(chan holder, 1024),
}
mutex.holder.Store(holder{})
return mutex
}
return &sync.RWMutex{}
}
@ -57,81 +62,129 @@ func NewWaitGroup() WaitGroup {
return &sync.WaitGroup{}
}
type holder struct {
at string
time time.Time
goid int
}
func (h holder) String() string {
if h.at == "" {
return "not held"
}
return fmt.Sprintf("at %s goid: %d for %s", h.at, h.goid, time.Now().Sub(h.time))
}
type loggedMutex struct {
sync.Mutex
start time.Time
lockedAt string
goid int
start time.Time
holder atomic.Value
}
func (m *loggedMutex) Lock() {
m.Mutex.Lock()
m.start = time.Now()
m.lockedAt = getCaller()
m.goid = goid()
m.holder.Store(getHolder())
}
func (m *loggedMutex) Unlock() {
duration := time.Now().Sub(m.start)
currentHolder := m.holder.Load().(holder)
duration := time.Now().Sub(currentHolder.time)
if duration >= threshold {
l.Debugf("Mutex held for %v. Locked at %s unlocked at %s", duration, m.lockedAt, getCaller())
l.Debugf("Mutex held for %v. Locked at %s unlocked at %s", duration, currentHolder.at, getHolder().at)
}
m.holder.Store(holder{})
m.Mutex.Unlock()
}
func (m *loggedMutex) Holder() (string, int) {
return m.lockedAt, m.goid
func (m *loggedMutex) Holders() string {
return m.holder.Load().(holder).String()
}
type loggedRWMutex struct {
sync.RWMutex
start time.Time
lockedAt string
goid int
holder atomic.Value
logUnlockers uint32
readHolders map[int][]holder
readHoldersMut sync.Mutex
unlockers []string
unlockersMut sync.Mutex
logUnlockers int32
unlockers chan holder
}
func (m *loggedRWMutex) Lock() {
start := time.Now()
atomic.StoreUint32(&m.logUnlockers, 1)
atomic.StoreInt32(&m.logUnlockers, 1)
m.RWMutex.Lock()
m.logUnlockers = 0
m.start = time.Now()
duration := m.start.Sub(start)
holder := getHolder()
m.holder.Store(holder)
duration := holder.time.Sub(start)
m.lockedAt = getCaller()
m.goid = goid()
if duration > threshold {
l.Debugf("RWMutex took %v to lock. Locked at %s. RUnlockers while locking: %s", duration, m.lockedAt, strings.Join(m.unlockers, ", "))
var unlockerStrings []string
loop:
for {
select {
case holder := <-m.unlockers:
unlockerStrings = append(unlockerStrings, holder.String())
default:
break loop
}
}
l.Debugf("RWMutex took %v to lock. Locked at %s. RUnlockers while locking:\n%s", duration, holder.at, strings.Join(unlockerStrings, "\n"))
}
m.unlockers = m.unlockers[0:]
}
func (m *loggedRWMutex) Unlock() {
duration := time.Now().Sub(m.start)
currentHolder := m.holder.Load().(holder)
duration := time.Now().Sub(currentHolder.time)
if duration >= threshold {
l.Debugf("RWMutex held for %v. Locked at %s: unlocked at %s", duration, m.lockedAt, getCaller())
l.Debugf("RWMutex held for %v. Locked at %s unlocked at %s", duration, currentHolder.at, getHolder().at)
}
m.holder.Store(holder{})
m.RWMutex.Unlock()
}
func (m *loggedRWMutex) RLock() {
m.RWMutex.RLock()
holder := getHolder()
m.readHoldersMut.Lock()
m.readHolders[holder.goid] = append(m.readHolders[holder.goid], holder)
m.readHoldersMut.Unlock()
}
func (m *loggedRWMutex) RUnlock() {
if atomic.LoadUint32(&m.logUnlockers) == 1 {
m.unlockersMut.Lock()
m.unlockers = append(m.unlockers, getCaller())
m.unlockersMut.Unlock()
id := goid()
m.readHoldersMut.Lock()
current := m.readHolders[id]
if len(current) > 0 {
m.readHolders[id] = current[:len(current)-1]
}
m.readHoldersMut.Unlock()
if atomic.LoadInt32(&m.logUnlockers) == 1 {
holder := getHolder()
select {
case m.unlockers <- holder:
default:
l.Debugf("Dropped holder %s as channel full", holder)
}
}
m.RWMutex.RUnlock()
}
func (m *loggedRWMutex) Holder() (string, int) {
return m.lockedAt, m.goid
func (m *loggedRWMutex) Holders() string {
output := m.holder.Load().(holder).String() + " (writer)"
m.readHoldersMut.Lock()
for _, holders := range m.readHolders {
for _, holder := range holders {
output += "\n" + holder.String() + " (reader)"
}
}
m.readHoldersMut.Unlock()
return output
}
type loggedWaitGroup struct {
@ -143,14 +196,18 @@ func (wg *loggedWaitGroup) Wait() {
wg.WaitGroup.Wait()
duration := time.Now().Sub(start)
if duration >= threshold {
l.Debugf("WaitGroup took %v at %s", duration, getCaller())
l.Debugf("WaitGroup took %v at %s", duration, getHolder())
}
}
func getCaller() string {
func getHolder() holder {
_, file, line, _ := runtime.Caller(2)
file = filepath.Join(filepath.Base(filepath.Dir(file)), filepath.Base(file))
return fmt.Sprintf("%s:%d", file, line)
return holder{
at: fmt.Sprintf("%s:%d", file, line),
goid: goid(),
time: time.Now(),
}
}
func goid() int {

View File

@ -162,7 +162,7 @@ func TestRWMutex(t *testing.T) {
if len(messages) != 2 {
t.Errorf("Unexpected message count")
}
if !strings.Contains(messages[1], "RUnlockers while locking: sync") || !strings.Contains(messages[1], "sync_test.go:") {
if !strings.Contains(messages[1], "RUnlockers while locking:\nat sync") || !strings.Contains(messages[1], "sync_test.go:") {
t.Error("Unexpected message")
}