metrics: optimize resetting timer, make influx resetting-timer span type use integer format

metrics/influxdb/influxdb.go

@@ -109,9 +109,9 @@ func readMeter(namespace, name string, i interface{}) (string, map[string]interf
 			"max":   t.Max(),
 			"mean":  t.Mean(),
 			"min":   t.Min(),
-			"p50":   ps[0],
+			"p50":   int(ps[0]),
-			"p95":   ps[1],
+			"p95":   int(ps[1]),
-			"p99":   ps[2],
+			"p99":   int(ps[2]),
 		}
 		return measurement, fields
 	}

metrics/influxdb/testdata/influxdbv1.want

@@ -5,5 +5,5 @@ goth.test/gauge_float64.gauge value=34567.89 978307200000000000
 goth.test/gauge_info.gauge value="{\"arch\":\"amd64\",\"commit\":\"7caa2d8163ae3132c1c2d6978c76610caee2d949\",\"os\":\"linux\",\"protocol_versions\":\"64 65 66\",\"version\":\"1.10.18-unstable\"}" 978307200000000000
 goth.test/histogram.histogram count=3i,max=3i,mean=2,min=1i,p25=1,p50=2,p75=3,p95=3,p99=3,p999=3,p9999=3,stddev=0.816496580927726,variance=0.6666666666666666 978307200000000000
 goth.test/meter.meter count=0i,m1=0,m15=0,m5=0,mean=0 978307200000000000
-goth.test/resetting_timer.span count=6i,max=120000000i,mean=30000000,min=10000000i,p50=12500000,p95=120000000,p99=120000000 978307200000000000
+goth.test/resetting_timer.span count=6i,max=120000000i,mean=30000000,min=10000000i,p50=12500000i,p95=120000000i,p99=120000000i 978307200000000000
 goth.test/timer.timer count=6i,m1=0,m15=0,m5=0,max=120000000i,mean=38333333.333333336,meanrate=0,min=20000000i,p50=22500000,p75=48000000,p95=120000000,p99=120000000,p999=120000000,p9999=120000000,stddev=36545253.529775314,variance=1335555555555555.2 978307200000000000

metrics/influxdb/testdata/influxdbv2.want

@@ -5,5 +5,5 @@ goth.test/gauge_float64.gauge value=34567.89 978307200000000000
 goth.test/gauge_info.gauge value="{\"arch\":\"amd64\",\"commit\":\"7caa2d8163ae3132c1c2d6978c76610caee2d949\",\"os\":\"linux\",\"protocol_versions\":\"64 65 66\",\"version\":\"1.10.18-unstable\"}" 978307200000000000
 goth.test/histogram.histogram count=3i,max=3i,mean=2,min=1i,p25=1,p50=2,p75=3,p95=3,p99=3,p999=3,p9999=3,stddev=0.816496580927726,variance=0.6666666666666666 978307200000000000
 goth.test/meter.meter count=0i,m1=0,m15=0,m5=0,mean=0 978307200000000000
-goth.test/resetting_timer.span count=6i,max=120000000i,mean=30000000,min=10000000i,p50=12500000,p95=120000000,p99=120000000 978307200000000000
+goth.test/resetting_timer.span count=6i,max=120000000i,mean=30000000,min=10000000i,p50=12500000i,p95=120000000i,p99=120000000i 978307200000000000
 goth.test/timer.timer count=6i,m1=0,m15=0,m5=0,max=120000000i,mean=38333333.333333336,meanrate=0,min=20000000i,p50=22500000,p75=48000000,p95=120000000,p99=120000000,p999=120000000,p9999=120000000,stddev=36545253.529775314,variance=1335555555555555.2 978307200000000000

metrics/resetting_timer.go

@@ -71,19 +71,22 @@ func (NilResettingTimer) Count() int                         { return 0 }
 // and Meter.
 type StandardResettingTimer struct {
 	values []int64
-	mutex  sync.Mutex
+	sum    int64 // sum is a running count of the total sum, used later to calculate mean
+
+	mutex sync.Mutex
 }
 
 // Snapshot resets the timer and returns a read-only copy of its contents.
 func (t *StandardResettingTimer) Snapshot() ResettingTimerSnapshot {
 	t.mutex.Lock()
 	defer t.mutex.Unlock()
-	currentValues := t.values
+	snapshot := &resettingTimerSnapshot{
-	t.values = make([]int64, 0, InitialResettingTimerSliceCap)
+		values: t.values,
-
+		mean:   float64(t.sum) / float64(len(t.values)),
-	return &resettingTimerSnapshot{
-		values: currentValues,
 	}
+	t.values = make([]int64, 0, InitialResettingTimerSliceCap)
+	t.sum = 0
+	return snapshot
 }
 
 // Record the duration of the execution of the given function.
@@ -98,13 +101,12 @@ func (t *StandardResettingTimer) Update(d time.Duration) {
 	t.mutex.Lock()
 	defer t.mutex.Unlock()
 	t.values = append(t.values, int64(d))
+	t.sum += int64(d)
 }
 
 // Record the duration of an event that started at a time and ends now.
 func (t *StandardResettingTimer) UpdateSince(ts time.Time) {
-	t.mutex.Lock()
+	t.Update(time.Since(ts))
-	defer t.mutex.Unlock()
-	t.values = append(t.values, int64(time.Since(ts)))
 }
 
 // resettingTimerSnapshot is a point-in-time copy of another ResettingTimer.
@@ -165,9 +167,4 @@ func (t *resettingTimerSnapshot) calc(percentiles []float64) {
 	}
 	t.min = t.values[0]
 	t.max = t.values[len(t.values)-1]
-	var sum int64
-	for _, v := range t.values {
-		sum += v
-	}
-	t.mean = float64(sum) / float64(len(t.values))
 }