Source: stat.go in package github.com/prometheus/procfs

Copyright 2018 The Prometheus Authors Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.


package procfs

import (
	"bufio"
	"bytes"
	"fmt"
	"io"
	"strconv"
	"strings"

	"github.com/prometheus/procfs/internal/fs"
	"github.com/prometheus/procfs/internal/util"
)

CPUStat shows how much time the cpu spend in various stages.

type CPUStat struct {
	User      float64
	Nice      float64
	System    float64
	Idle      float64
	Iowait    float64
	IRQ       float64
	SoftIRQ   float64
	Steal     float64
	Guest     float64
	GuestNice float64
}

SoftIRQStat represent the softirq statistics as exported in the procfs stat file. A nice introduction can be found at https://0xax.gitbooks.io/linux-insides/content/interrupts/interrupts-9.html It is possible to get per-cpu stats by reading /proc/softirqs

type SoftIRQStat struct {
	Hi          uint64
	Timer       uint64
	NetTx       uint64
	NetRx       uint64
	Block       uint64
	BlockIoPoll uint64
	Tasklet     uint64
	Sched       uint64
	Hrtimer     uint64
	Rcu         uint64
}

Stat represents kernel/system statistics.

Boot time in seconds since the Epoch.

Summed up cpu statistics.

Per-CPU statistics.

Number of times interrupts were handled, which contains numbered and unnumbered IRQs.

Number of times a numbered IRQ was triggered.

Number of times a context switch happened.

Number of times a process was created.

Number of processes currently running.

Number of processes currently blocked (waiting for IO).

Number of times a softirq was scheduled.

Detailed softirq statistics.

	SoftIRQ SoftIRQStat
}

Parse a cpu statistics line and returns the CPUStat struct plus the cpu id (or -1 for the overall sum).

func parseCPUStat(line string) (CPUStat, int64, error) {
	cpuStat := CPUStat{}
	var cpu string

	count, err := fmt.Sscanf(line, "%s %f %f %f %f %f %f %f %f %f %f",
		&cpu,
		&cpuStat.User, &cpuStat.Nice, &cpuStat.System, &cpuStat.Idle,
		&cpuStat.Iowait, &cpuStat.IRQ, &cpuStat.SoftIRQ, &cpuStat.Steal,
		&cpuStat.Guest, &cpuStat.GuestNice)

	if err != nil && err != io.EOF {
		return CPUStat{}, -1, fmt.Errorf("couldn't parse %s (cpu): %s", line, err)
	}
	if count == 0 {
		return CPUStat{}, -1, fmt.Errorf("couldn't parse %s (cpu): 0 elements parsed", line)
	}

	cpuStat.User /= userHZ
	cpuStat.Nice /= userHZ
	cpuStat.System /= userHZ
	cpuStat.Idle /= userHZ
	cpuStat.Iowait /= userHZ
	cpuStat.IRQ /= userHZ
	cpuStat.SoftIRQ /= userHZ
	cpuStat.Steal /= userHZ
	cpuStat.Guest /= userHZ
	cpuStat.GuestNice /= userHZ

	if cpu == "cpu" {
		return cpuStat, -1, nil
	}

	cpuID, err := strconv.ParseInt(cpu[3:], 10, 64)
	if err != nil {
		return CPUStat{}, -1, fmt.Errorf("couldn't parse %s (cpu/cpuid): %s", line, err)
	}

	return cpuStat, cpuID, nil
}

Parse a softirq line.

func parseSoftIRQStat(line string) (SoftIRQStat, uint64, error) {
	softIRQStat := SoftIRQStat{}
	var total uint64
	var prefix string

	_, err := fmt.Sscanf(line, "%s %d %d %d %d %d %d %d %d %d %d %d",
		&prefix, &total,
		&softIRQStat.Hi, &softIRQStat.Timer, &softIRQStat.NetTx, &softIRQStat.NetRx,
		&softIRQStat.Block, &softIRQStat.BlockIoPoll,
		&softIRQStat.Tasklet, &softIRQStat.Sched,
		&softIRQStat.Hrtimer, &softIRQStat.Rcu)

	if err != nil {
		return SoftIRQStat{}, 0, fmt.Errorf("couldn't parse %s (softirq): %s", line, err)
	}

	return softIRQStat, total, nil
}

NewStat returns information about current cpu/process statistics. See https://www.kernel.org/doc/Documentation/filesystems/proc.txt Deprecated: use fs.Stat() instead

func NewStat() (Stat, error) {
	fs, err := NewFS(fs.DefaultProcMountPoint)
	if err != nil {
		return Stat{}, err
	}
	return fs.Stat()
}

NewStat returns information about current cpu/process statistics. See https://www.kernel.org/doc/Documentation/filesystems/proc.txt Deprecated: use fs.Stat() instead

func (fs FS) NewStat() (Stat, error) {
	return fs.Stat()
}

Stat returns information about current cpu/process statistics. See https://www.kernel.org/doc/Documentation/filesystems/proc.txt

func (fs FS) Stat() (Stat, error) {
	fileName := fs.proc.Path("stat")
	data, err := util.ReadFileNoStat(fileName)
	if err != nil {
		return Stat{}, err
	}

	stat := Stat{}

	scanner := bufio.NewScanner(bytes.NewReader(data))
	for scanner.Scan() {
		line := scanner.Text()

require at least <key> <value>

		if len(parts) < 2 {
			continue
		}
		switch {
		case parts[0] == "btime":
			if stat.BootTime, err = strconv.ParseUint(parts[1], 10, 64); err != nil {
				return Stat{}, fmt.Errorf("couldn't parse %s (btime): %s", parts[1], err)
			}
		case parts[0] == "intr":
			if stat.IRQTotal, err = strconv.ParseUint(parts[1], 10, 64); err != nil {
				return Stat{}, fmt.Errorf("couldn't parse %s (intr): %s", parts[1], err)
			}
			numberedIRQs := parts[2:]
			stat.IRQ = make([]uint64, len(numberedIRQs))
			for i, count := range numberedIRQs {
				if stat.IRQ[i], err = strconv.ParseUint(count, 10, 64); err != nil {
					return Stat{}, fmt.Errorf("couldn't parse %s (intr%d): %s", count, i, err)
				}
			}
		case parts[0] == "ctxt":
			if stat.ContextSwitches, err = strconv.ParseUint(parts[1], 10, 64); err != nil {
				return Stat{}, fmt.Errorf("couldn't parse %s (ctxt): %s", parts[1], err)
			}
		case parts[0] == "processes":
			if stat.ProcessCreated, err = strconv.ParseUint(parts[1], 10, 64); err != nil {
				return Stat{}, fmt.Errorf("couldn't parse %s (processes): %s", parts[1], err)
			}
		case parts[0] == "procs_running":
			if stat.ProcessesRunning, err = strconv.ParseUint(parts[1], 10, 64); err != nil {
				return Stat{}, fmt.Errorf("couldn't parse %s (procs_running): %s", parts[1], err)
			}
		case parts[0] == "procs_blocked":
			if stat.ProcessesBlocked, err = strconv.ParseUint(parts[1], 10, 64); err != nil {
				return Stat{}, fmt.Errorf("couldn't parse %s (procs_blocked): %s", parts[1], err)
			}
		case parts[0] == "softirq":
			softIRQStats, total, err := parseSoftIRQStat(line)
			if err != nil {
				return Stat{}, err
			}
			stat.SoftIRQTotal = total
			stat.SoftIRQ = softIRQStats
		case strings.HasPrefix(parts[0], "cpu"):
			cpuStat, cpuID, err := parseCPUStat(line)
			if err != nil {
				return Stat{}, err
			}
			if cpuID == -1 {
				stat.CPUTotal = cpuStat
			} else {
				for int64(len(stat.CPU)) <= cpuID {
					stat.CPU = append(stat.CPU, CPUStat{})
				}
				stat.CPU[cpuID] = cpuStat
			}
		}
	}

	if err := scanner.Err(); err != nil {
		return Stat{}, fmt.Errorf("couldn't parse %s: %s", fileName, err)
	}

	return stat, nil