source: code/trunk/vendor/github.com/prometheus/procfs/stat.go@ 822

// 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.
type Stat struct {
        // Boot time in seconds since the Epoch.
        BootTime uint64
        // Summed up cpu statistics.
        CPUTotal CPUStat
        // Per-CPU statistics.
        CPU []CPUStat
        // Number of times interrupts were handled, which contains numbered and unnumbered IRQs.
        IRQTotal uint64
        // Number of times a numbered IRQ was triggered.
        IRQ []uint64
        // Number of times a context switch happened.
        ContextSwitches uint64
        // Number of times a process was created.
        ProcessCreated uint64
        // Number of processes currently running.
        ProcessesRunning uint64
        // Number of processes currently blocked (waiting for IO).
        ProcessesBlocked uint64
        // Number of times a softirq was scheduled.
        SoftIRQTotal uint64
        // 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 %q (cpu): %w", line, err)
        }
        if count == 0 {
                return CPUStat{}, -1, fmt.Errorf("couldn't parse %q (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 %q (cpu/cpuid): %w", 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 %q (softirq): %w", 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()
                parts := strings.Fields(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 %q (btime): %w", 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 %q (intr): %w", 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 %q (intr%d): %w", 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 %q (ctxt): %w", 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 %q (processes): %w", 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 %q (procs_running): %w", 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 %q (procs_blocked): %w", 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 %q: %w", fileName, err)
        }

        return stat, nil
}