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|
package sync
import (
"runtime"
"sync"
"time"
)
type Mutex struct {
mu sync.Mutex
hold *int // Unique value for passing to pprof.
stack [32]uintptr // The stack for the current holder.
start time.Time // When the lock was obtained.
entries int // Number of entries returned from runtime.Callers.
}
func (m *Mutex) Lock() {
if contentionOn {
v := new(int)
lockBlockers.Add(v, 0)
m.mu.Lock()
lockBlockers.Remove(v)
m.hold = v
lockHolders.Add(v, 0)
} else {
m.mu.Lock()
}
if lockTimesOn {
m.entries = runtime.Callers(2, m.stack[:])
m.start = time.Now()
}
}
func (m *Mutex) Unlock() {
if lockTimesOn {
d := time.Since(m.start)
var key [32]uintptr
copy(key[:], m.stack[:m.entries])
lockStatsMu.Lock()
v, ok := lockStatsByStack[key]
if !ok {
v.Init()
}
v.Add(d)
lockStatsByStack[key] = v
lockStatsMu.Unlock()
}
if contentionOn {
lockHolders.Remove(m.hold)
}
m.mu.Unlock()
}
|
