From 7961599b2e41c71720a42b3bfde641f7529f05fe Mon Sep 17 00:00:00 2001
From: Corey Hulen <corey@hulen.com>
Date: Tue, 22 Nov 2016 11:05:54 -0800
Subject: PLT-4357 adding performance monitoring (#4622)

* WIP

* WIP

* Adding metrics collection

* updating vendor packages

* Adding metrics to config

* Adding admin console page for perf monitoring

* Updating glide

* switching to tylerb/graceful
---
 vendor/github.com/beorn7/perks/topk/topk.go      | 90 ++++++++++++++++++++++++
 vendor/github.com/beorn7/perks/topk/topk_test.go | 57 +++++++++++++++
 2 files changed, 147 insertions(+)
 create mode 100644 vendor/github.com/beorn7/perks/topk/topk.go
 create mode 100644 vendor/github.com/beorn7/perks/topk/topk_test.go

(limited to 'vendor/github.com/beorn7/perks/topk')

diff --git a/vendor/github.com/beorn7/perks/topk/topk.go b/vendor/github.com/beorn7/perks/topk/topk.go
new file mode 100644
index 000000000..5ac3d9904
--- /dev/null
+++ b/vendor/github.com/beorn7/perks/topk/topk.go
@@ -0,0 +1,90 @@
+package topk
+
+import (
+	"sort"
+)
+
+// http://www.cs.ucsb.edu/research/tech_reports/reports/2005-23.pdf
+
+type Element struct {
+	Value string
+	Count int
+}
+
+type Samples []*Element
+
+func (sm Samples) Len() int {
+	return len(sm)
+}
+
+func (sm Samples) Less(i, j int) bool {
+	return sm[i].Count < sm[j].Count
+}
+
+func (sm Samples) Swap(i, j int) {
+	sm[i], sm[j] = sm[j], sm[i]
+}
+
+type Stream struct {
+	k   int
+	mon map[string]*Element
+
+	// the minimum Element
+	min *Element
+}
+
+func New(k int) *Stream {
+	s := new(Stream)
+	s.k = k
+	s.mon = make(map[string]*Element)
+	s.min = &Element{}
+
+	// Track k+1 so that less frequenet items contended for that spot,
+	// resulting in k being more accurate.
+	return s
+}
+
+func (s *Stream) Insert(x string) {
+	s.insert(&Element{x, 1})
+}
+
+func (s *Stream) Merge(sm Samples) {
+	for _, e := range sm {
+		s.insert(e)
+	}
+}
+
+func (s *Stream) insert(in *Element) {
+	e := s.mon[in.Value]
+	if e != nil {
+		e.Count++
+	} else {
+		if len(s.mon) < s.k+1 {
+			e = &Element{in.Value, in.Count}
+			s.mon[in.Value] = e
+		} else {
+			e = s.min
+			delete(s.mon, e.Value)
+			e.Value = in.Value
+			e.Count += in.Count
+			s.min = e
+		}
+	}
+	if e.Count < s.min.Count {
+		s.min = e
+	}
+}
+
+func (s *Stream) Query() Samples {
+	var sm Samples
+	for _, e := range s.mon {
+		sm = append(sm, e)
+	}
+	sort.Sort(sort.Reverse(sm))
+
+	if len(sm) < s.k {
+		return sm
+	}
+
+	return sm[:s.k]
+}
diff --git a/vendor/github.com/beorn7/perks/topk/topk_test.go b/vendor/github.com/beorn7/perks/topk/topk_test.go
new file mode 100644
index 000000000..c24f0f727
--- /dev/null
+++ b/vendor/github.com/beorn7/perks/topk/topk_test.go
@@ -0,0 +1,57 @@
+package topk
+
+import (
+	"fmt"
+	"math/rand"
+	"sort"
+	"testing"
+)
+
+func TestTopK(t *testing.T) {
+	stream := New(10)
+	ss := []*Stream{New(10), New(10), New(10)}
+	m := make(map[string]int)
+	for _, s := range ss {
+		for i := 0; i < 1e6; i++ {
+			v := fmt.Sprintf("%x", int8(rand.ExpFloat64()))
+			s.Insert(v)
+			m[v]++
+		}
+		stream.Merge(s.Query())
+	}
+
+	var sm Samples
+	for x, s := range m {
+		sm = append(sm, &Element{x, s})
+	}
+	sort.Sort(sort.Reverse(sm))
+
+	g := stream.Query()
+	if len(g) != 10 {
+		t.Fatalf("got %d, want 10", len(g))
+	}
+	for i, e := range g {
+		if sm[i].Value != e.Value {
+			t.Errorf("at %d: want %q, got %q", i, sm[i].Value, e.Value)
+		}
+	}
+}
+
+func TestQuery(t *testing.T) {
+	queryTests := []struct {
+		value string
+		expected int
+	}{
+		{"a", 1},
+		{"b", 2},
+		{"c", 2},
+	}
+
+	stream := New(2)
+	for _, tt := range queryTests {
+		stream.Insert(tt.value)
+		if n := len(stream.Query()); n != tt.expected {
+			t.Errorf("want %d, got %d", tt.expected, n)
+		}
+	}
+}
-- 
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