Implement #2250: Add "isolated" label on cpu collector on linux

Signed-off-by: david <davidventura27@gmail.com>

collector/cpu_linux.go

@@ -18,9 +18,11 @@ package collector
 
 import (
 	"fmt"
+	"io/ioutil"
 	"path/filepath"
 	"regexp"
 	"strconv"
+	"strings"
 	"sync"
 
 	"github.com/go-kit/log"
@@ -42,6 +44,7 @@ type cpuCollector struct {
 	logger             log.Logger
 	cpuStats           []procfs.CPUStat
 	cpuStatsMutex      sync.Mutex
+	isolatedCpus       []uint16
 
 	cpuFlagsIncludeRegexp *regexp.Regexp
 	cpuBugsIncludeRegexp  *regexp.Regexp
@@ -62,15 +65,69 @@ func init() {
 	registerCollector("cpu", defaultEnabled, NewCPUCollector)
 }
 
+func parseIsolCpus(data []byte) ([]uint16, error) {
+	isolcpus_str := strings.TrimRight(string(data), "\n")
+
+	var isolcpus_int = []uint16{}
+
+	for _, cpu := range strings.Split(isolcpus_str, ",") {
+		if cpu == "" {
+			continue
+		}
+		if strings.Contains(cpu, "-") {
+			ranges := strings.Split(cpu, "-")
+			startRange, err := strconv.Atoi(ranges[0])
+			if err != nil {
+				return nil, err
+			}
+			endRange, err := strconv.Atoi(ranges[1])
+			if err != nil {
+				return nil, err
+			}
+
+			for i := startRange; i <= endRange; i++ {
+				isolcpus_int = append(isolcpus_int, uint16(i))
+			}
+			continue
+		}
+
+		_cpu, err := strconv.Atoi(cpu)
+		if err != nil {
+			return nil, err
+		}
+		isolcpus_int = append(isolcpus_int, uint16(_cpu))
+	}
+	return isolcpus_int, nil
+}
+
+func readIsolCpus() ([]uint16, error) {
+	isolcpus, err := ioutil.ReadFile(sysFilePath("devices/system/cpu/isolated"))
+	if err != nil {
+		return nil, fmt.Errorf("failed to read isolcpus from sysfs: %w", err)
+	}
+
+	return parseIsolCpus(isolcpus)
+}
+
 // NewCPUCollector returns a new Collector exposing kernel/system statistics.
 func NewCPUCollector(logger log.Logger) (Collector, error) {
 	fs, err := procfs.NewFS(*procPath)
 	if err != nil {
 		return nil, fmt.Errorf("failed to open procfs: %w", err)
 	}
+
+	isolcpus, err := readIsolCpus()
+	if err != nil {
+		return nil, fmt.Errorf("failed to open procfs: %w", err)
+	}
+
 	c := &cpuCollector{
 		fs: fs,
-		cpu: nodeCPUSecondsDesc,
+		cpu: prometheus.NewDesc(
+			prometheus.BuildFQName(namespace, cpuCollectorSubsystem, "seconds_total"),
+			"Seconds the CPUs spent in each mode.",
+			[]string{"cpu", "mode", "isolated"}, nil,
+		),
 		cpuInfo: prometheus.NewDesc(
 			prometheus.BuildFQName(namespace, cpuCollectorSubsystem, "info"),
 			"CPU information from /proc/cpuinfo.",
@@ -89,7 +146,7 @@ func NewCPUCollector(logger log.Logger) (Collector, error) {
 		cpuGuest: prometheus.NewDesc(
 			prometheus.BuildFQName(namespace, cpuCollectorSubsystem, "guest_seconds_total"),
 			"Seconds the CPUs spent in guests (VMs) for each mode.",
-			[]string{"cpu", "mode"}, nil,
+			[]string{"cpu", "mode", "isolated"}, nil,
 		),
 		cpuCoreThrottle: prometheus.NewDesc(
 			prometheus.BuildFQName(namespace, cpuCollectorSubsystem, "core_throttles_total"),
@@ -102,6 +159,7 @@ func NewCPUCollector(logger log.Logger) (Collector, error) {
 			[]string{"package"}, nil,
 		),
 		logger:       logger,
+		isolatedCpus: isolcpus,
 	}
 	err = c.compileIncludeFlags(flagsInclude, bugsInclude)
 	if err != nil {
@@ -276,6 +334,15 @@ func (c *cpuCollector) updateThermalThrottle(ch chan<- prometheus.Metric) error
 	return nil
 }
 
+func contains(s []uint16, e uint16) bool {
+	for _, a := range s {
+		if a == e {
+			return true
+		}
+	}
+	return false
+}
+
 // updateStat reads /proc/stat through procfs and exports CPU-related metrics.
 func (c *cpuCollector) updateStat(ch chan<- prometheus.Metric) error {
 	stats, err := c.fs.Stat()
@@ -290,19 +357,23 @@ func (c *cpuCollector) updateStat(ch chan<- prometheus.Metric) error {
 	defer c.cpuStatsMutex.Unlock()
 	for cpuID, cpuStat := range c.cpuStats {
 		cpuNum := strconv.Itoa(cpuID)
-		ch <- prometheus.MustNewConstMetric(c.cpu, prometheus.CounterValue, cpuStat.User, cpuNum, "user")
+		isIsolated := "0"
-		ch <- prometheus.MustNewConstMetric(c.cpu, prometheus.CounterValue, cpuStat.Nice, cpuNum, "nice")
+		if contains(c.isolatedCpus, uint16(cpuID)) {
-		ch <- prometheus.MustNewConstMetric(c.cpu, prometheus.CounterValue, cpuStat.System, cpuNum, "system")
+			isIsolated = "1"
-		ch <- prometheus.MustNewConstMetric(c.cpu, prometheus.CounterValue, cpuStat.Idle, cpuNum, "idle")
+		}
-		ch <- prometheus.MustNewConstMetric(c.cpu, prometheus.CounterValue, cpuStat.Iowait, cpuNum, "iowait")
+		ch <- prometheus.MustNewConstMetric(c.cpu, prometheus.CounterValue, cpuStat.User, cpuNum, "user", isIsolated)
-		ch <- prometheus.MustNewConstMetric(c.cpu, prometheus.CounterValue, cpuStat.IRQ, cpuNum, "irq")
+		ch <- prometheus.MustNewConstMetric(c.cpu, prometheus.CounterValue, cpuStat.Nice, cpuNum, "nice", isIsolated)
-		ch <- prometheus.MustNewConstMetric(c.cpu, prometheus.CounterValue, cpuStat.SoftIRQ, cpuNum, "softirq")
+		ch <- prometheus.MustNewConstMetric(c.cpu, prometheus.CounterValue, cpuStat.System, cpuNum, "system", isIsolated)
-		ch <- prometheus.MustNewConstMetric(c.cpu, prometheus.CounterValue, cpuStat.Steal, cpuNum, "steal")
+		ch <- prometheus.MustNewConstMetric(c.cpu, prometheus.CounterValue, cpuStat.Idle, cpuNum, "idle", isIsolated)
+		ch <- prometheus.MustNewConstMetric(c.cpu, prometheus.CounterValue, cpuStat.Iowait, cpuNum, "iowait", isIsolated)
+		ch <- prometheus.MustNewConstMetric(c.cpu, prometheus.CounterValue, cpuStat.IRQ, cpuNum, "irq", isIsolated)
+		ch <- prometheus.MustNewConstMetric(c.cpu, prometheus.CounterValue, cpuStat.SoftIRQ, cpuNum, "softirq", isIsolated)
+		ch <- prometheus.MustNewConstMetric(c.cpu, prometheus.CounterValue, cpuStat.Steal, cpuNum, "steal", isIsolated)
 
 		if *enableCPUGuest {
 			// Guest CPU is also accounted for in cpuStat.User and cpuStat.Nice, expose these as separate metrics.
-			ch <- prometheus.MustNewConstMetric(c.cpuGuest, prometheus.CounterValue, cpuStat.Guest, cpuNum, "user")
+			ch <- prometheus.MustNewConstMetric(c.cpuGuest, prometheus.CounterValue, cpuStat.Guest, cpuNum, "user", isIsolated)
-			ch <- prometheus.MustNewConstMetric(c.cpuGuest, prometheus.CounterValue, cpuStat.GuestNice, cpuNum, "nice")
+			ch <- prometheus.MustNewConstMetric(c.cpuGuest, prometheus.CounterValue, cpuStat.GuestNice, cpuNum, "nice", isIsolated)
 		}
 	}
 

collector/cpu_linux_test.go

@@ -104,3 +104,31 @@ func TestCPU(t *testing.T) {
 		t.Fatalf("should have %v CPU Stat: got %v", resetIdle, got)
 	}
 }
+func TestIsolatedParsingCPU(t *testing.T) {
+	var testParams = []struct {
+		in  []byte
+		res []uint16
+		err error
+	}{
+		{[]byte(""), []uint16{}, nil},
+		{[]byte("1\n"), []uint16{1}, nil},
+		{[]byte("1"), []uint16{1}, nil},
+		{[]byte("1,2"), []uint16{1, 2}, nil},
+		{[]byte("1-2"), []uint16{1, 2}, nil},
+		{[]byte("1-3"), []uint16{1, 2, 3}, nil},
+		{[]byte("1,2-4"), []uint16{1, 2, 3, 4}, nil},
+		{[]byte("1,3-4"), []uint16{1, 3, 4}, nil},
+		{[]byte("1,3-4,7,20-21"), []uint16{1, 3, 4, 7, 20, 21}, nil},
+	}
+	for _, params := range testParams {
+		t.Run("blabla", func(t *testing.T) {
+			res, err := parseIsolCpus(params.in)
+			if !reflect.DeepEqual(res, params.res) {
+				t.Fatalf("should have %v result: got %v", params.res, res)
+			}
+			if err != params.err {
+				t.Fatalf("should have %v error: got %v", params.err, err)
+			}
+		})
+	}
+}