Vendor psutils and remove neko

plugins/system/ps/cpu/cpu_unix.go

@@ -0,0 +1,61 @@
+// +build linux freebsd darwin
+
+package cpu
+
+import "time"
+
+func init() {
+	lastCPUTimes, _ = CPUTimes(false)
+	lastPerCPUTimes, _ = CPUTimes(true)
+}
+
+func CPUPercent(interval time.Duration, percpu bool) ([]float64, error) {
+	getAllBusy := func(t CPUTimesStat) (float64, float64) {
+		busy := t.User + t.System + t.Nice + t.Iowait + t.Irq +
+			t.Softirq + t.Steal + t.Guest + t.GuestNice + t.Stolen
+		return busy + t.Idle, busy
+	}
+
+	calculate := func(t1, t2 CPUTimesStat) float64 {
+		t1All, t1Busy := getAllBusy(t1)
+		t2All, t2Busy := getAllBusy(t2)
+
+		if t2Busy <= t1Busy {
+			return 0
+		}
+		if t2All <= t1All {
+			return 1
+		}
+		return (t2Busy - t1Busy) / (t2All - t1All) * 100
+	}
+
+	cpuTimes, err := CPUTimes(percpu)
+	if err != nil {
+		return nil, err
+	}
+
+	if interval > 0 {
+		if !percpu {
+			lastCPUTimes = cpuTimes
+		} else {
+			lastPerCPUTimes = cpuTimes
+		}
+		time.Sleep(interval)
+		cpuTimes, err = CPUTimes(percpu)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	ret := make([]float64, len(cpuTimes))
+	if !percpu {
+		ret[0] = calculate(lastCPUTimes[0], cpuTimes[0])
+		lastCPUTimes = cpuTimes
+	} else {
+		for i, t := range cpuTimes {
+			ret[i] = calculate(lastPerCPUTimes[i], t)
+		}
+		lastPerCPUTimes = cpuTimes
+	}
+	return ret, nil
+}