initial import

core/stat/internal/cpu_linux.go

@@ -0,0 +1,148 @@
+package internal
+
+import (
+	"errors"
+	"fmt"
+	"strings"
+	"time"
+
+	"zero/core/iox"
+	"zero/core/lang"
+)
+
+const (
+	cpuTicks  = 100
+	cpuFields = 8
+)
+
+var (
+	preSystem uint64
+	preTotal  uint64
+	quota     float64
+	cores     uint64
+)
+
+func init() {
+	cpus, err := perCpuUsage()
+	lang.Must(err)
+	cores = uint64(len(cpus))
+
+	sets, err := cpuSets()
+	lang.Must(err)
+	quota = float64(len(sets))
+	cq, err := cpuQuota()
+	if err == nil {
+		if cq != -1 {
+			period, err := cpuPeriod()
+			lang.Must(err)
+
+			limit := float64(cq) / float64(period)
+			if limit < quota {
+				quota = limit
+			}
+		}
+	}
+
+	preSystem, err = systemCpuUsage()
+	lang.Must(err)
+
+	preTotal, err = totalCpuUsage()
+	lang.Must(err)
+}
+
+func RefreshCpu() uint64 {
+	total, err := totalCpuUsage()
+	if err != nil {
+		return 0
+	}
+	system, err := systemCpuUsage()
+	if err != nil {
+		return 0
+	}
+
+	var usage uint64
+	cpuDelta := total - preTotal
+	systemDelta := system - preSystem
+	if cpuDelta > 0 && systemDelta > 0 {
+		usage = uint64(float64(cpuDelta*cores*1e3) / (float64(systemDelta) * quota))
+	}
+	preSystem = system
+	preTotal = total
+
+	return usage
+}
+
+func cpuQuota() (int64, error) {
+	cg, err := currentCgroup()
+	if err != nil {
+		return 0, err
+	}
+
+	return cg.cpuQuotaUs()
+}
+
+func cpuPeriod() (uint64, error) {
+	cg, err := currentCgroup()
+	if err != nil {
+		return 0, err
+	}
+
+	return cg.cpuPeriodUs()
+}
+
+func cpuSets() ([]uint64, error) {
+	cg, err := currentCgroup()
+	if err != nil {
+		return nil, err
+	}
+
+	return cg.cpus()
+}
+
+func perCpuUsage() ([]uint64, error) {
+	cg, err := currentCgroup()
+	if err != nil {
+		return nil, err
+	}
+
+	return cg.acctUsagePerCpu()
+}
+
+func systemCpuUsage() (uint64, error) {
+	lines, err := iox.ReadTextLines("/proc/stat", iox.WithoutBlank())
+	if err != nil {
+		return 0, err
+	}
+
+	for _, line := range lines {
+		fields := strings.Fields(line)
+		if fields[0] == "cpu" {
+			if len(fields) < cpuFields {
+				return 0, fmt.Errorf("bad format of cpu stats")
+			}
+
+			var totalClockTicks uint64
+			for _, i := range fields[1:cpuFields] {
+				v, err := parseUint(i)
+				if err != nil {
+					return 0, err
+				}
+
+				totalClockTicks += v
+			}
+
+			return (totalClockTicks * uint64(time.Second)) / cpuTicks, nil
+		}
+	}
+
+	return 0, errors.New("bad stats format")
+}
+
+func totalCpuUsage() (usage uint64, err error) {
+	var cg *cgroup
+	if cg, err = currentCgroup(); err != nil {
+		return
+	}
+
+	return cg.acctUsageAllCpus()
+}