// writeMutex writes the current mutex profile to w.
func writeMutex(w io.Writer, debug int) error {
// TODO(pjw): too much common code with writeBlock. FIX!
var p []runtime.BlockProfileRecord
n, ok := runtime.MutexProfile(nil)
for {
p = make([]runtime.BlockProfileRecord, n+50)
n, ok = runtime.MutexProfile(p)
if ok {
p = p[:n]
break
}
}
sort.Slice(p, func(i, j int) bool { return p[i].Cycles > p[j].Cycles })
b := bufio.NewWriter(w)
var tw *tabwriter.Writer
w = b
if debug > 0 {
tw = tabwriter.NewWriter(w, 1, 8, 1, '\t', 0)
w = tw
}
fmt.Fprintf(w, "--- mutex:\n")
fmt.Fprintf(w, "cycles/second=%v\n", runtime_cyclesPerSecond())
fmt.Fprintf(w, "sampling period=%d\n", runtime.SetMutexProfileFraction(-1))
for i := range p {
r := &p[i]
fmt.Fprintf(w, "%v %v @", r.Cycles, r.Count)
for _, pc := range r.Stack() {
fmt.Fprintf(w, " %#x", pc)
}
fmt.Fprint(w, "\n")
if debug > 0 {
printStackRecord(w, r.Stack(), true)
}
}
if tw != nil {
tw.Flush()
}
return b.Flush()
}
// countMutex returns the number of records in the mutex profile.
func countMutex() int {
n, _ := runtime.MutexProfile(nil)
return n
}