monitor: Remove Distribution() method and test.

Follow up to #939. Fixes #1586.

monitor/metrics/store.go

@@ -175,25 +175,6 @@ func (mtrs *Store) PeerLatest(name string, pid peer.ID) *api.Metric {
 	return m
 }
 
-// Distribution returns the distribution of a particular metrics
-// for a particular peer.
-func (mtrs *Store) Distribution(name string, pid peer.ID) []float64 {
-	mtrs.mux.RLock()
-	defer mtrs.mux.RUnlock()
-
-	byPeer, ok := mtrs.byName[name]
-	if !ok {
-		return nil
-	}
-
-	window, ok := byPeer[pid]
-	if !ok {
-		return nil
-	}
-
-	return window.Distribution()
-}
-
 // MetricNames returns all the known metric names
 func (mtrs *Store) MetricNames() []string {
 	mtrs.mux.RLock()

monitor/metrics/window.go

@@ -91,20 +91,3 @@ func (mw *Window) All() []*api.Metric {
 
 	return values
 }
-
-// Distribution returns the deltas between all the current
-// values contained in the current window. This will
-// only return values if the api.Metric.Type() is "ping",
-// which are used for accural failure detection.
-func (mw *Window) Distribution() []float64 {
-	ms := mw.All()
-	dist := make([]float64, 0, len(ms)-1)
-	// the last value can't be used to calculate a delta
-	for i, v := range ms[:len(ms)-1] {
-		// All() provides an order slice, where ms[i] is younger than ms[i+1]
-		delta := v.ReceivedAt - ms[i+1].ReceivedAt
-		dist = append(dist, float64(delta))
-	}
-
-	return dist
-}

monitor/metrics/window_test.go

@@ -2,7 +2,6 @@ package metrics
 
 import (
 	"fmt"
-	"strconv"
 	"testing"
 	"time"
 
@@ -83,20 +82,6 @@ func TestWindow_Race(t *testing.T) {
 		}
 	}()
 
-	// go routine to query distribution at regular interval
-	distributionTicker := time.NewTicker(100 * time.Millisecond)
-	go func() {
-		<-start
-		for {
-			select {
-			case <-distributionTicker.C:
-				log <- fmt.Sprintf("dist: %v", w.Distribution())
-			case <-done:
-				return
-			}
-		}
-	}()
-
 	go func() {
 		<-start
 		<-done
@@ -342,103 +327,3 @@ func BenchmarkWindow_All(b *testing.B) {
 		}
 	})
 }
-
-func TestWindow_Distribution(t *testing.T) {
-	var tests = []struct {
-		name       string
-		heartbeats []float64
-		want       []float64
-	}{
-		{
-			"even 1 sec distribution",
-			[]float64{1, 1, 1, 1},
-			[]float64{1, 1, 1, 1},
-		},
-		{
-			"increasing latency distribution",
-			[]float64{1, 1, 2, 2, 3, 3, 4},
-			[]float64{4, 3, 3, 2, 2, 1, 1},
-		},
-		{
-			"random latency distribution",
-			[]float64{4, 1, 3, 9, 7, 8, 11, 18},
-			[]float64{18, 11, 8, 7, 9, 3, 1, 4},
-		},
-	}
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			mw := NewWindow(len(tt.heartbeats) + 1)
-			for i, v := range tt.heartbeats {
-				mw.Add(makeMetric(strconv.Itoa(int(v * 10))))
-				// time.Sleep on the 1s of milliseconds level is
-				// susceptible to scheduler variance. Hence we
-				// multiple the input by 10 and this combined with
-				// truncating the result to just seconds, we should
-				// get stable distribution of timings between
-				// window.Adds.
-				time.Sleep(time.Duration(v*10) * time.Millisecond)
-				if i == len(tt.heartbeats)-1 {
-					mw.Add(makeMetric("last"))
-				}
-			}
-
-			got := mw.Distribution()
-
-			if len(got) != len(tt.want) {
-				t.Errorf("want len: %v, got len: %v", len(tt.want), len(got))
-			}
-
-			var gotseconds []float64
-			for _, v := range got {
-				// truncate nanoseconds to seconds for testing purposes
-				// also truncate decimal places by converting to int and then back
-				gotseconds = append(gotseconds, float64(int64(v/10000000)))
-			}
-
-			for i, s := range gotseconds {
-				if s != tt.want[i] {
-					t.Fatalf("want: %v, got: %v", tt.want, gotseconds)
-					break
-				}
-			}
-		})
-	}
-}
-
-func BenchmarkWindow_Distribution(b *testing.B) {
-	b.Run("window size 10", func(b *testing.B) {
-		mw := NewWindow(10)
-		for i := 0; i < 10; i++ {
-			mw.Add(makeMetric("1"))
-		}
-
-		b.ResetTimer()
-		for i := 0; i < b.N; i++ {
-			mw.Distribution()
-		}
-	})
-
-	b.Run("window size 25", func(b *testing.B) {
-		mw := NewWindow(25)
-		for i := 0; i < 25; i++ {
-			mw.Add(makeMetric("1"))
-		}
-
-		b.ResetTimer()
-		for i := 0; i < b.N; i++ {
-			mw.Distribution()
-		}
-	})
-
-	b.Run("window size 1000", func(b *testing.B) {
-		mw := NewWindow(1000)
-		for i := 0; i < 1000; i++ {
-			mw.Add(makeMetric("1"))
-		}
-
-		b.ResetTimer()
-		for i := 0; i < b.N; i++ {
-			mw.Distribution()
-		}
-	})
-}