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76 lines
1.8 KiB
Go
76 lines
1.8 KiB
Go
//go:build !windows
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// +build !windows
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package stats // import "github.com/docker/docker/daemon/stats"
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import (
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"fmt"
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"os"
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"strconv"
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"strings"
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"golang.org/x/sys/unix"
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)
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const (
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// The value comes from `C.sysconf(C._SC_CLK_TCK)`, and
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// on Linux it's a constant which is safe to be hard coded,
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// so we can avoid using cgo here. For details, see:
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// https://github.com/containerd/cgroups/pull/12
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clockTicksPerSecond = 100
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nanoSecondsPerSecond = 1e9
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)
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// getSystemCPUUsage returns the host system's cpu usage in
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// nanoseconds. An error is returned if the format of the underlying
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// file does not match.
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//
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// Uses /proc/stat defined by POSIX. Looks for the cpu
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// statistics line and then sums up the first seven fields
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// provided. See `man 5 proc` for details on specific field
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// information.
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func (s *Collector) getSystemCPUUsage() (uint64, error) {
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f, err := os.Open("/proc/stat")
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if err != nil {
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return 0, err
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}
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defer func() {
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s.bufReader.Reset(nil)
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f.Close()
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}()
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s.bufReader.Reset(f)
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for {
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line, err := s.bufReader.ReadString('\n')
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if err != nil {
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break
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}
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parts := strings.Fields(line)
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switch parts[0] {
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case "cpu":
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if len(parts) < 8 {
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return 0, fmt.Errorf("invalid number of cpu fields")
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}
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var totalClockTicks uint64
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for _, i := range parts[1:8] {
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v, err := strconv.ParseUint(i, 10, 64)
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if err != nil {
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return 0, fmt.Errorf("Unable to convert value %s to int: %s", i, err)
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}
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totalClockTicks += v
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}
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return (totalClockTicks * nanoSecondsPerSecond) /
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clockTicksPerSecond, nil
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}
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}
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return 0, fmt.Errorf("invalid stat format. Error trying to parse the '/proc/stat' file")
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}
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func (s *Collector) getNumberOnlineCPUs() (uint32, error) {
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var cpuset unix.CPUSet
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err := unix.SchedGetaffinity(0, &cpuset)
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if err != nil {
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return 0, err
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}
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return uint32(cpuset.Count()), nil
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}
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