Function parseThread

profile/legacy_profile.go:840–920

parseThread parses a Threadz profile and returns a new Profile.

(b []byte)

// parseThread parses a Threadz profile and returns a new Profile.
func parseThread(b []byte) (*Profile, error) {
	s := bufio.NewScanner(bytes.NewBuffer(b))
	// Skip past comments and empty lines seeking a real header.
	for s.Scan() && isSpaceOrComment(s.Text()) {
	}

	line := s.Text()
	if m := threadzStartRE.FindStringSubmatch(line); m != nil {
		// Advance over initial comments until first stack trace.
		for s.Scan() {
			if line = s.Text(); isMemoryMapSentinel(line) || strings.HasPrefix(line, "-") {
				break
			}
		}
	} else if t := threadStartRE.FindStringSubmatch(line); len(t) != 4 {
		return nil, errUnrecognized
	}

	p := &Profile{
		SampleType: []*ValueType{{Type: "thread", Unit: "count"}},
		PeriodType: &ValueType{Type: "thread", Unit: "count"},
		Period:     1,
	}

	locs := make(map[uint64]*Location)
	// Recognize each thread and populate profile samples.
	for !isMemoryMapSentinel(line) {
		if strings.HasPrefix(line, "---- no stack trace for") {
			break
		}
		if t := threadStartRE.FindStringSubmatch(line); len(t) != 4 {
			return nil, errUnrecognized
		}

		var addrs []uint64
		var err error
		line, addrs, err = parseThreadSample(s)
		if err != nil {
			return nil, err
		}
		if len(addrs) == 0 {
			// We got a --same as previous threads--. Bump counters.
			if len(p.Sample) > 0 {
				s := p.Sample[len(p.Sample)-1]
				s.Value[0]++
			}
			continue
		}

		var sloc []*Location
		for i, addr := range addrs {
			// Addresses from stack traces point to the next instruction after
			// each call. Adjust by -1 to land somewhere on the actual call
			// (except for the leaf, which is not a call).
			if i > 0 {
				addr--
			}
			loc := locs[addr]