Rebase and fixups for PR #111

CHANGELOG.md

@@ -15,6 +15,8 @@
 - [#103](https://github.com/influxdb/telegraf/pull/103): Filter by metric tags. Thanks @srfraser!
 - [#106](https://github.com/influxdb/telegraf/pull/106): Options to filter plugins on startup. Thanks @zepouet!
 - [#107](https://github.com/influxdb/telegraf/pull/107): Multiple outputs beyong influxdb. Thanks @jipperinbham!
+- [#108](https://github.com/influxdb/telegraf/issues/108): Support setting per-CPU and total-CPU gathering.
+- [#111](https://github.com/influxdb/telegraf/pull/111): Report CPU Usage in cpu plugin. Thanks @jpalay!
 
 ### Bugfixes
 - [#85](https://github.com/influxdb/telegraf/pull/85): Fix GetLocalHost testutil function for mac users

plugins/system/cpu.go

@@ -10,19 +10,9 @@ import (
 type CPUStats struct {
 	ps        PS
 	lastStats []cpu.CPUTimesStat
-
-    PerCPU   bool `toml:"percpu"`
-    TotalCPU bool `toml:"totalcpu"`
-}
-
-func NewCPUStats(ps PS) *CPUStats {
-	times, _ := ps.CPUTimes()
-	stats := CPUStats{
-		ps:        ps,
-		lastStats: times,
-	}
 
-	return &stats
+	PerCPU   bool `toml:"percpu"`
+	TotalCPU bool `toml:"totalcpu"`
 }
 
 func (_ *CPUStats) Description() string {
@@ -67,6 +57,10 @@ func (s *CPUStats) Gather(acc plugins.Accumulator) error {
 		add(acc, "busy", busy, tags)
 
 		// Add in percentage
+		if len(s.lastStats) == 0 {
+			// If it's the 1st gather, can't get CPU stats yet
+			continue
+		}
 		lastCts := s.lastStats[i]
 		lastBusy, lastTotal := busyAndTotalCpuTime(lastCts)
 		busyDelta := busy - lastBusy
@@ -77,7 +71,7 @@ func (s *CPUStats) Gather(acc plugins.Accumulator) error {
 		}
 
 		if totalDelta == 0 {
-			return nil
+			continue
 		}
 
 		add(acc, "percentageUser", 100*(cts.User-lastCts.User)/totalDelta, tags)
@@ -110,7 +104,6 @@ func busyAndTotalCpuTime(t cpu.CPUTimesStat) (float64, float64) {
 
 func init() {
 	plugins.Add("cpu", func() plugins.Plugin {
-		realPS := &systemPS{}
-		return NewCPUStats(realPS)
+		return &CPUStats{ps: &systemPS{}}
 	})
 }