mirror of
https://github.com/prometheus/node_exporter.git
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3565316d7e
Cache CPU metrics to avoid counters (ie iowait) jumping backwards. Fixes: https://github.com/prometheus/node_exporter/issues/1686 Signed-off-by: Ben Kochie <superq@gmail.com>
307 lines
11 KiB
Go
307 lines
11 KiB
Go
// Copyright 2015 The Prometheus Authors
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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// +build !nocpu
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package collector
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import (
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"fmt"
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"path/filepath"
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"strconv"
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"sync"
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"github.com/go-kit/kit/log"
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"github.com/go-kit/kit/log/level"
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"github.com/prometheus/client_golang/prometheus"
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"github.com/prometheus/procfs"
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"gopkg.in/alecthomas/kingpin.v2"
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)
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type cpuCollector struct {
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fs procfs.FS
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cpu *prometheus.Desc
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cpuInfo *prometheus.Desc
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cpuGuest *prometheus.Desc
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cpuCoreThrottle *prometheus.Desc
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cpuPackageThrottle *prometheus.Desc
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logger log.Logger
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cpuStats []procfs.CPUStat
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cpuStatsMutex sync.Mutex
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}
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var (
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enableCPUInfo = kingpin.Flag("collector.cpu.info", "Enables metric cpu_info").Bool()
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)
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func init() {
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registerCollector("cpu", defaultEnabled, NewCPUCollector)
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}
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// NewCPUCollector returns a new Collector exposing kernel/system statistics.
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func NewCPUCollector(logger log.Logger) (Collector, error) {
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fs, err := procfs.NewFS(*procPath)
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if err != nil {
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return nil, fmt.Errorf("failed to open procfs: %w", err)
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}
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return &cpuCollector{
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fs: fs,
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cpu: nodeCPUSecondsDesc,
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cpuInfo: prometheus.NewDesc(
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prometheus.BuildFQName(namespace, cpuCollectorSubsystem, "info"),
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"CPU information from /proc/cpuinfo.",
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[]string{"package", "core", "cpu", "vendor", "family", "model", "model_name", "microcode", "stepping", "cachesize"}, nil,
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),
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cpuGuest: prometheus.NewDesc(
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prometheus.BuildFQName(namespace, cpuCollectorSubsystem, "guest_seconds_total"),
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"Seconds the cpus spent in guests (VMs) for each mode.",
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[]string{"cpu", "mode"}, nil,
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),
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cpuCoreThrottle: prometheus.NewDesc(
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prometheus.BuildFQName(namespace, cpuCollectorSubsystem, "core_throttles_total"),
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"Number of times this cpu core has been throttled.",
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[]string{"package", "core"}, nil,
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),
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cpuPackageThrottle: prometheus.NewDesc(
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prometheus.BuildFQName(namespace, cpuCollectorSubsystem, "package_throttles_total"),
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"Number of times this cpu package has been throttled.",
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[]string{"package"}, nil,
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),
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logger: logger,
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}, nil
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}
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// Update implements Collector and exposes cpu related metrics from /proc/stat and /sys/.../cpu/.
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func (c *cpuCollector) Update(ch chan<- prometheus.Metric) error {
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if *enableCPUInfo {
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if err := c.updateInfo(ch); err != nil {
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return err
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}
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}
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if err := c.updateStat(ch); err != nil {
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return err
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}
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if err := c.updateThermalThrottle(ch); err != nil {
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return err
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}
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return nil
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}
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// updateInfo reads /proc/cpuinfo
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func (c *cpuCollector) updateInfo(ch chan<- prometheus.Metric) error {
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info, err := c.fs.CPUInfo()
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if err != nil {
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return err
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}
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for _, cpu := range info {
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ch <- prometheus.MustNewConstMetric(c.cpuInfo,
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prometheus.GaugeValue,
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1,
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cpu.PhysicalID,
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cpu.CoreID,
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strconv.Itoa(int(cpu.Processor)),
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cpu.VendorID,
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cpu.CPUFamily,
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cpu.Model,
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cpu.ModelName,
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cpu.Microcode,
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cpu.Stepping,
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cpu.CacheSize)
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}
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return nil
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}
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// updateThermalThrottle reads /sys/devices/system/cpu/cpu* and expose thermal throttle statistics.
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func (c *cpuCollector) updateThermalThrottle(ch chan<- prometheus.Metric) error {
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cpus, err := filepath.Glob(sysFilePath("devices/system/cpu/cpu[0-9]*"))
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if err != nil {
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return err
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}
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packageThrottles := make(map[uint64]uint64)
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packageCoreThrottles := make(map[uint64]map[uint64]uint64)
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// cpu loop
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for _, cpu := range cpus {
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// See
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// https://www.kernel.org/doc/Documentation/x86/topology.txt
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// https://www.kernel.org/doc/Documentation/cputopology.txt
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// https://www.kernel.org/doc/Documentation/ABI/testing/sysfs-devices-system-cpu
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var err error
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var physicalPackageID, coreID uint64
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// topology/physical_package_id
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if physicalPackageID, err = readUintFromFile(filepath.Join(cpu, "topology", "physical_package_id")); err != nil {
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level.Debug(c.logger).Log("msg", "CPU is missing physical_package_id", "cpu", cpu)
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continue
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}
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// topology/core_id
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if coreID, err = readUintFromFile(filepath.Join(cpu, "topology", "core_id")); err != nil {
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level.Debug(c.logger).Log("msg", "CPU is missing core_id", "cpu", cpu)
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continue
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}
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// metric node_cpu_core_throttles_total
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//
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// We process this metric before the package throttles as there
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// are cpu+kernel combinations that only present core throttles
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// but no package throttles.
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// Seen e.g. on an Intel Xeon E5472 system with RHEL 6.9 kernel.
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if _, present := packageCoreThrottles[physicalPackageID]; !present {
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packageCoreThrottles[physicalPackageID] = make(map[uint64]uint64)
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}
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if _, present := packageCoreThrottles[physicalPackageID][coreID]; !present {
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// Read thermal_throttle/core_throttle_count only once
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if coreThrottleCount, err := readUintFromFile(filepath.Join(cpu, "thermal_throttle", "core_throttle_count")); err == nil {
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packageCoreThrottles[physicalPackageID][coreID] = coreThrottleCount
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} else {
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level.Debug(c.logger).Log("msg", "CPU is missing core_throttle_count", "cpu", cpu)
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}
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}
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// metric node_cpu_package_throttles_total
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if _, present := packageThrottles[physicalPackageID]; !present {
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// Read thermal_throttle/package_throttle_count only once
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if packageThrottleCount, err := readUintFromFile(filepath.Join(cpu, "thermal_throttle", "package_throttle_count")); err == nil {
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packageThrottles[physicalPackageID] = packageThrottleCount
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} else {
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level.Debug(c.logger).Log("msg", "CPU is missing package_throttle_count", "cpu", cpu)
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}
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}
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}
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for physicalPackageID, packageThrottleCount := range packageThrottles {
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ch <- prometheus.MustNewConstMetric(c.cpuPackageThrottle,
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prometheus.CounterValue,
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float64(packageThrottleCount),
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strconv.FormatUint(physicalPackageID, 10))
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}
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for physicalPackageID, coreMap := range packageCoreThrottles {
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for coreID, coreThrottleCount := range coreMap {
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ch <- prometheus.MustNewConstMetric(c.cpuCoreThrottle,
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prometheus.CounterValue,
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float64(coreThrottleCount),
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strconv.FormatUint(physicalPackageID, 10),
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strconv.FormatUint(coreID, 10))
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}
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}
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return nil
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}
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// updateStat reads /proc/stat through procfs and exports cpu related metrics.
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func (c *cpuCollector) updateStat(ch chan<- prometheus.Metric) error {
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stats, err := c.fs.Stat()
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if err != nil {
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return err
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}
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c.updateCPUStats(stats.CPU)
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// Acquire a lock to read the stats.
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c.cpuStatsMutex.Lock()
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defer c.cpuStatsMutex.Unlock()
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for cpuID, cpuStat := range c.cpuStats {
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cpuNum := strconv.Itoa(cpuID)
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ch <- prometheus.MustNewConstMetric(c.cpu, prometheus.CounterValue, cpuStat.User, cpuNum, "user")
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ch <- prometheus.MustNewConstMetric(c.cpu, prometheus.CounterValue, cpuStat.Nice, cpuNum, "nice")
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ch <- prometheus.MustNewConstMetric(c.cpu, prometheus.CounterValue, cpuStat.System, cpuNum, "system")
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ch <- prometheus.MustNewConstMetric(c.cpu, prometheus.CounterValue, cpuStat.Idle, cpuNum, "idle")
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ch <- prometheus.MustNewConstMetric(c.cpu, prometheus.CounterValue, cpuStat.Iowait, cpuNum, "iowait")
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ch <- prometheus.MustNewConstMetric(c.cpu, prometheus.CounterValue, cpuStat.IRQ, cpuNum, "irq")
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ch <- prometheus.MustNewConstMetric(c.cpu, prometheus.CounterValue, cpuStat.SoftIRQ, cpuNum, "softirq")
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ch <- prometheus.MustNewConstMetric(c.cpu, prometheus.CounterValue, cpuStat.Steal, cpuNum, "steal")
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// Guest CPU is also accounted for in cpuStat.User and cpuStat.Nice, expose these as separate metrics.
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ch <- prometheus.MustNewConstMetric(c.cpuGuest, prometheus.CounterValue, cpuStat.Guest, cpuNum, "user")
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ch <- prometheus.MustNewConstMetric(c.cpuGuest, prometheus.CounterValue, cpuStat.GuestNice, cpuNum, "nice")
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}
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return nil
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}
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// updateCPUStats updates the internal cache of CPU stats.
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func (c *cpuCollector) updateCPUStats(newStats []procfs.CPUStat) {
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// Acquire a lock to update the stats.
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c.cpuStatsMutex.Lock()
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defer c.cpuStatsMutex.Unlock()
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// Reset the cache if the list of CPUs has changed.
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if len(c.cpuStats) != len(newStats) {
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c.cpuStats = make([]procfs.CPUStat, len(newStats))
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}
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for i, n := range newStats {
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// If idle jumps backwards, assume we had a hotplug event and reset the stats for this CPU.
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if n.Idle < c.cpuStats[i].Idle {
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level.Warn(c.logger).Log("msg", "CPU Idle counter jumped backwards, possible hotplug event, resetting CPU stats", "cpu", i, "old_value", c.cpuStats[i].Idle, "new_value", n.Idle)
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c.cpuStats[i] = procfs.CPUStat{}
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}
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c.cpuStats[i].Idle = n.Idle
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if n.User >= c.cpuStats[i].User {
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c.cpuStats[i].User = n.User
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} else {
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level.Warn(c.logger).Log("msg", "CPU User counter jumped backwards", "cpu", i, "old_value", c.cpuStats[i].User, "new_value", n.User)
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}
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if n.Nice >= c.cpuStats[i].Nice {
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c.cpuStats[i].Nice = n.Nice
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} else {
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level.Warn(c.logger).Log("msg", "CPU Nice counter jumped backwards", "cpu", i, "old_value", c.cpuStats[i].Nice, "new_value", n.Nice)
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}
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if n.System >= c.cpuStats[i].System {
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c.cpuStats[i].System = n.System
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} else {
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level.Warn(c.logger).Log("msg", "CPU System counter jumped backwards", "cpu", i, "old_value", c.cpuStats[i].System, "new_value", n.System)
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}
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if n.Iowait >= c.cpuStats[i].Iowait {
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c.cpuStats[i].Iowait = n.Iowait
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} else {
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level.Warn(c.logger).Log("msg", "CPU Iowait counter jumped backwards", "cpu", i, "old_value", c.cpuStats[i].Iowait, "new_value", n.Iowait)
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}
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if n.IRQ >= c.cpuStats[i].IRQ {
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c.cpuStats[i].IRQ = n.IRQ
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} else {
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level.Warn(c.logger).Log("msg", "CPU IRQ counter jumped backwards", "cpu", i, "old_value", c.cpuStats[i].IRQ, "new_value", n.IRQ)
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}
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if n.SoftIRQ >= c.cpuStats[i].SoftIRQ {
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c.cpuStats[i].SoftIRQ = n.SoftIRQ
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} else {
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level.Warn(c.logger).Log("msg", "CPU SoftIRQ counter jumped backwards", "cpu", i, "old_value", c.cpuStats[i].SoftIRQ, "new_value", n.SoftIRQ)
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}
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if n.Steal >= c.cpuStats[i].Steal {
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c.cpuStats[i].Steal = n.Steal
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} else {
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level.Warn(c.logger).Log("msg", "CPU Steal counter jumped backwards", "cpu", i, "old_value", c.cpuStats[i].Steal, "new_value", n.Steal)
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}
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if n.Guest >= c.cpuStats[i].Guest {
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c.cpuStats[i].Guest = n.Guest
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} else {
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level.Warn(c.logger).Log("msg", "CPU Guest counter jumped backwards", "cpu", i, "old_value", c.cpuStats[i].Guest, "new_value", n.Guest)
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}
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if n.GuestNice >= c.cpuStats[i].GuestNice {
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c.cpuStats[i].GuestNice = n.GuestNice
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} else {
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level.Warn(c.logger).Log("msg", "CPU GuestNice counter jumped backwards", "cpu", i, "old_value", c.cpuStats[i].GuestNice, "new_value", n.GuestNice)
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}
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}
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}
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