func NewSchedulerLoadReader() (SchedulerLoadReader, error) {
schedDebug, err := fs.Open("/proc/sched_debug")
if err != nil {
return nil, err
}
scanner := bufio.NewScanner(schedDebug)
stateMachine := newSchedDebugReader()
for scanner.Scan() {
line := scanner.Text()
err = stateMachine.ProcessLine(line)
if err != nil {
return nil, err
}
}
if err = scanner.Err(); err != nil {
return nil, err
}
return stateMachine.Load()
}
// Given a container name, returns the parent and name of the container to be fed to libcontainer.
func SplitName(containerName string) (string, string, error) {
parent, id := path.Split(containerName)
cgroupSelf, err := fs.Open("/proc/1/cgroup")
if err != nil {
return "", "", err
}
scanner := bufio.NewScanner(cgroupSelf)
// Find how nested we are. Libcontainer takes container names relative to the current process.
subsys := []string{"memory", "cpu"}
nestedLevels := 0
for scanner.Scan() {
line := scanner.Text()
elems := strings.Split(line, ":")
if len(elems) < 3 {
continue
}
for _, s := range subsys {
if elems[1] == s {
if elems[2] == "/" {
// We're running at root, no nesting.
nestedLevels = 0
} else {
// Count how deeply nested we are.
nestedLevels = strings.Count(elems[2], "/")
}
break
}
}
}
if nestedLevels > 0 {
// we are running inside a docker container
upperLevel := strings.Repeat("../", nestedLevels)
parent = filepath.Join(upperLevel, parent)
}
// Strip the last "/"
if parent[len(parent)-1] == '/' {
parent = parent[:len(parent)-1]
}
return parent, id, nil
}
// Add() read the schedstat of pid, and add stat to the fields
// in self parameters. This function is useful if one wants to read stats of
// a group of processes.
func (self *ProcessSchedStat) Add(pid int) error {
if self == nil {
return fmt.Errorf("nil stat")
}
path := fmt.Sprintf("/proc/%d/schedstat", pid)
f, err := fs.Open(path)
if err != nil {
return err
}
defer f.Close()
v, err := readUint64List(f)
if err != nil {
return err
}
if len(v) < 3 {
return fmt.Errorf("only %v fields read from %v: %v", len(v), path, v)
}
self.Running += v[0]
self.RunWait += v[1]
self.NumTimeSlices += v[2]
self.NumProcesses++
return nil
}