Add CPU frequency collector

collectors/cpufreqMetric.go

@@ -0,0 +1,189 @@
+package collectors
+
+import (
+	"bufio"
+	"encoding/json"
+	"fmt"
+	"log"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"time"
+
+	lp "github.com/influxdata/line-protocol"
+	"golang.org/x/sys/unix"
+)
+
+var warnLog *log.Logger = log.New(os.Stderr, "Warning: ", log.LstdFlags)
+
+//
+// readOneLine reads one line from a file.
+// It returns ok when file was successfully read.
+// In this case text contains the first line of the files contents.
+//
+func readOneLine(filename string) (text string, ok bool) {
+	file, err := os.Open(filename)
+	if err != nil {
+		return
+	}
+	defer file.Close()
+	scanner := bufio.NewScanner(file)
+	ok = scanner.Scan()
+	text = scanner.Text()
+	return
+}
+
+type CPUFreqCollectorCPU struct {
+	// coreID, packageID, num_cores, num_package
+	tagSet             map[string]string
+	scalingCurFreqFile string
+}
+
+//
+// CPUFreqCollector
+// a metric collector to measure the current frequency of the CPUs
+// as obtained from the hardware (in KHz)
+// Only measure on the first hyper thread
+//
+// See: https://www.kernel.org/doc/html/latest/admin-guide/pm/cpufreq.html
+//
+type CPUFreqCollector struct {
+	MetricCollector
+	config struct {
+		ExcludeMetrics []string `json:"exclude_metrics,omitempty"`
+	}
+	cpus []CPUFreqCollectorCPU
+}
+
+func (m *CPUFreqCollector) Init(config []byte) error {
+	m.name = "CPUFreqCollector"
+	m.setup()
+	if len(config) > 0 {
+		err := json.Unmarshal(config, &m.config)
+		if err != nil {
+			return err
+		}
+	}
+
+	// Initialize CPU list
+	m.cpus = make([]CPUFreqCollectorCPU, 0)
+
+	// Loop for all CPU directories
+	baseDir := "/sys/devices/system/cpu"
+	globPattern := filepath.Join(baseDir, "cpu[0-9]*")
+	cpuDirs, err := filepath.Glob(globPattern)
+	if err != nil {
+		return fmt.Errorf("CPUFreqCollector.Init() unable to glob files with pattern %s: %v", globPattern, err)
+	}
+	if cpuDirs == nil {
+		return fmt.Errorf("CPUFreqCollector.Init() unable to find any files with pattern %s", globPattern)
+	}
+
+	maxPackageID := 0
+	maxCoreID := 0
+	for _, cpuDir := range cpuDirs {
+		cpuID := strings.TrimPrefix(cpuDir, "/sys/devices/system/cpu/cpu")
+
+		// Read thread sibling list
+		threadSiblingListFile := filepath.Join(cpuDir, "topology", "thread_siblings_list")
+		threadSiblingList, ok := readOneLine(threadSiblingListFile)
+		if !ok {
+			return fmt.Errorf("CPUFreqCollector.Init() unable to read thread siblings list from %s", threadSiblingListFile)
+		}
+
+		// Read frequency only from first hardware thread
+		// Ignore Simultaneous Multithreading (SMT) / Hyper-Threading
+		if strings.Split(threadSiblingList, ",")[0] == cpuID {
+			// Read package ID
+			packageIDFile := filepath.Join(cpuDir, "topology", "physical_package_id")
+			packageID, ok := readOneLine(packageIDFile)
+			if !ok {
+				return fmt.Errorf("CPUFreqCollector.Init() unable to read physical package ID from %s", packageIDFile)
+			}
+			packageID_int, err := strconv.Atoi(packageID)
+			if err != nil {
+				return fmt.Errorf("CPUFreqCollector.Init() unable to convert packageID to int: %v", err)
+			}
+
+			// Update maxPackageID
+			if packageID_int > maxPackageID {
+				maxPackageID = packageID_int
+			}
+
+			// Read core ID
+			coreIDFile := filepath.Join(cpuDir, "topology", "core_id")
+			coreID, ok := readOneLine(coreIDFile)
+			if !ok {
+				return fmt.Errorf("CPUFreqCollector.Init() unable to read core ID from %s", coreIDFile)
+			}
+			coreID_int, err := strconv.Atoi(coreID)
+			if err != nil {
+				return fmt.Errorf("CPUFreqCollector.Init() unable to convert coreID to int: %v", err)
+			}
+
+			// Update maxCoreID
+			if coreID_int > maxCoreID {
+				maxCoreID = coreID_int
+			}
+
+			// Check access to current frequency file
+			scalingCurFreqFile := filepath.Join(cpuDir, "cpufreq", "scaling_cur_freq")
+			err = unix.Access(scalingCurFreqFile, unix.R_OK)
+			if err != nil {
+				return fmt.Errorf("CPUFreqCollector.Init() unable to access %s: %v", scalingCurFreqFile, err)
+			}
+
+			m.cpus = append(
+				m.cpus,
+				CPUFreqCollectorCPU{
+					tagSet: map[string]string{
+						"coreID":    strings.TrimSpace(coreID),
+						"packageID": strings.TrimSpace(packageID),
+					},
+					scalingCurFreqFile: scalingCurFreqFile,
+				})
+		}
+	}
+
+	// Add num packages and num cores as tags
+	numPackages := strconv.Itoa(maxPackageID + 1)
+	numCores := strconv.Itoa(maxCoreID + 1)
+	for i := range m.cpus {
+		m.cpus[i].tagSet["num_core"] = numCores
+		m.cpus[i].tagSet["num_package"] = numPackages
+	}
+
+	m.init = true
+	return nil
+}
+
+func (m *CPUFreqCollector) Read(interval time.Duration, out *[]lp.MutableMetric) {
+	if !m.init {
+		return
+	}
+
+	for _, cpu := range m.cpus {
+		// Read current frequency
+		line, ok := readOneLine(cpu.scalingCurFreqFile)
+		if !ok {
+			warnLog.Printf("CPUFreqCollector.Read(): Failed to read one line from file '%s'", cpu.scalingCurFreqFile)
+			continue
+		}
+		cpuFreq, err := strconv.Atoi(line)
+		if err != nil {
+			warnLog.Printf("CPUFreqCollector.Read(): Failed to convert CPU frequency '%s': %v", line, err)
+			continue
+		}
+
+		value := map[string]interface{}{"value": cpuFreq}
+		y, err := lp.New("cpufreq", cpu.tagSet, value, time.Now())
+		if err == nil {
+			*out = append(*out, y)
+		}
+	}
+}
+
+func (m *CPUFreqCollector) Close() {
+	m.init = false
+}