TOOLS-911 mongostat uses sample time to calculate throughput

3 files changed, 18 insertions, 11 deletions

diff --git a/mongostat/mongostat.go b/mongostat/mongostat.go
index 16aaf2ecf15..4c9fe0f2d42 100644
--- a/mongostat/mongostat.go
+++ b/mongostat/mongostat.go
@@ -240,7 +240,7 @@ func NewNodeMonitor(opts options.ToolOptions, fullHost string, all bool) (*NodeM
 
 // Report collects the stat info for a single node, and sends the result on
 // the "out" channel. If it fails, the error is stored in the NodeMonitor Err field.
-func (node *NodeMonitor) Poll(discover chan string, all bool, checkShards bool, sampleSecs int64) *StatLine {
+func (node *NodeMonitor) Poll(discover chan string, all bool, checkShards bool) *StatLine {
 	result := &ServerStatus{}
 	log.Logf(log.DebugHigh, "getting session on server: %v", node.host)
 	s, err := node.sessionProvider.GetSession()
@@ -280,7 +280,7 @@ func (node *NodeMonitor) Poll(discover chan string, all bool, checkShards bool,
 
 	var statLine *StatLine
 	if node.LastStatus != nil && result != nil {
-		statLine = NewStatLine(*node.LastStatus, *result, node.host, all, sampleSecs)
+		statLine = NewStatLine(*node.LastStatus, *result, node.host, all)
 	}
 
 	if result.Repl != nil && discover != nil {
@@ -314,9 +314,9 @@ func (node *NodeMonitor) Watch(sleep time.Duration, discover chan string, cluste
 	go func() {
 		cycle := uint64(0)
 		for {
-			sampleDiff := int64(sleep / time.Second)
 			log.Logf(log.DebugHigh, "polling server: %v", node.host)
-			statLine := node.Poll(discover, node.All, cycle%10 == 1, sampleDiff)
+			statLine := node.Poll(discover, node.All, cycle%10 == 1)
+
 			if statLine != nil {
 				log.Logf(log.DebugHigh, "successfully got statline from host: %v", node.host)
 				cluster.Update(*statLine)
diff --git a/mongostat/mongostat_test.go b/mongostat/mongostat_test.go
index e0e30cbe842..d8896e478e5 100644
--- a/mongostat/mongostat_test.go
+++ b/mongostat/mongostat_test.go
@@ -12,8 +12,11 @@ func TestStatLine(t *testing.T) {
 
 	faultsOld := int64(10)
 	faultsNew := int64(15)
+	timeOld, _ := time.Parse("2006 Jan 02 15:04:05", "2015 Nov 30 4:25:30")
+	timeNew1, _ := time.Parse("2006 Jan 02 15:04:05", "2015 Nov 30 4:25:31")
+	timeNew3, _ := time.Parse("2006 Jan 02 15:04:05", "2015 Nov 30 4:25:33")
 	serverStatusOld := ServerStatus{
-		SampleTime:     time.Now(),
+		SampleTime:     timeOld,
 		Host:           "localhost",
 		Version:        "test-version",
 		Process:        "mongod",
@@ -100,7 +103,7 @@ func TestStatLine(t *testing.T) {
 	}
 
 	serverStatusNew := ServerStatus{
-		SampleTime:     time.Now(),
+		SampleTime:     timeNew1,
 		Host:           "localhost",
 		Version:        "test-version",
 		Process:        "mongod",
@@ -187,7 +190,7 @@ func TestStatLine(t *testing.T) {
 	}
 
 	Convey("StatsLine should accurately calculate opcounter diffs", t, func() {
-		statsLine := NewStatLine(serverStatusOld, serverStatusNew, "", false, 1)
+		statsLine := NewStatLine(serverStatusOld, serverStatusNew, "", false)
 		So(statsLine.Insert, ShouldEqual, 10)
 		So(statsLine.Query, ShouldEqual, 5)
 		So(statsLine.Update, ShouldEqual, 7)
@@ -207,8 +210,9 @@ func TestStatLine(t *testing.T) {
 		So(statsLine.NumConnections, ShouldEqual, 5)
 	})
 
+	serverStatusNew.SampleTime = timeNew3
 	Convey("StatsLine with non-default interval should calculate average diffs", t, func() {
-		statsLine := NewStatLine(serverStatusOld, serverStatusNew, "", false, 3)
+		statsLine := NewStatLine(serverStatusOld, serverStatusNew, "", false)
 		// Opcounters and faults are averaged over sample period
 		So(statsLine.Insert, ShouldEqual, 3)
 		So(statsLine.Query, ShouldEqual, 1)
diff --git a/mongostat/stat_types.go b/mongostat/stat_types.go
index 6602f795a1c..11d99ba6044 100644
--- a/mongostat/stat_types.go
+++ b/mongostat/stat_types.go
@@ -735,12 +735,12 @@ func (glf *GridLineFormatter) FormatLines(lines []StatLine, index int, discover
 	return returnVal
 }
 
-func diff(newVal, oldVal, sampleTime int64) int64 {
-	return (newVal - oldVal) / sampleTime
+func diff(newVal, oldVal int64, sampleSecs float64) int64 {
+	return int64(float64(newVal-oldVal) / sampleSecs)
 }
 
 // NewStatLine constructs a StatLine object from two ServerStatus objects.
-func NewStatLine(oldStat, newStat ServerStatus, key string, all bool, sampleSecs int64) *StatLine {
+func NewStatLine(oldStat, newStat ServerStatus, key string, all bool) *StatLine {
 	returnVal := &StatLine{
 		Key:       key,
 		Host:      newStat.Host,
@@ -758,6 +758,9 @@ func NewStatLine(oldStat, newStat ServerStatus, key string, all bool, sampleSecs
 		returnVal.StorageEngine = "mmapv1"
 	}
 
+	// Find the number of seconds that have elapsed since the last sample.
+	sampleSecs := float64(newStat.SampleTime.Sub(oldStat.SampleTime).Seconds())
+
 	if newStat.Opcounters != nil && oldStat.Opcounters != nil {
 		returnVal.Insert = diff(newStat.Opcounters.Insert, oldStat.Opcounters.Insert, sampleSecs)
 		returnVal.Query = diff(newStat.Opcounters.Query, oldStat.Opcounters.Query, sampleSecs)