Merge pull request #32298 from wojtek-t/hwm_in_cacher

Automatic merge from submit-queue

Log water mark for incoming queue in cacher

Ref #32257

pkg/storage/cacher.go

@@ -162,7 +162,8 @@ type Cacher struct {
 	watchers   indexedWatchers
 
 	// Incoming events that should be dispatched to watchers.
-	incoming chan watchCacheEvent
+	incoming    chan watchCacheEvent
+	incomingHWM HighWaterMark
 
 	// Handling graceful termination.
 	stopLock sync.RWMutex
@@ -410,6 +411,10 @@ func (c *Cacher) triggerValues(event *watchCacheEvent) ([]string, bool) {
 }
 
 func (c *Cacher) processEvent(event watchCacheEvent) {
+	if curLen := int64(len(c.incoming)); c.incomingHWM.Update(curLen) {
+		// Monitor if this gets backed up, and how much.
+		glog.V(1).Infof("cacher (%v): %v objects queued in incoming channel.", c.objectType.String(), curLen)
+	}
 	c.incoming <- event
 }
 

pkg/storage/etcd/etcd_watcher.go

@@ -21,7 +21,6 @@ import (
 	"net/http"
 	"reflect"
 	"sync"
-	"sync/atomic"
 	"time"
 
 	"k8s.io/kubernetes/pkg/api/unversioned"
@@ -47,23 +46,6 @@ const (
 	EtcdExpire = "expire"
 )
 
-// HighWaterMark is a thread-safe object for tracking the maximum value seen
-// for some quantity.
-type HighWaterMark int64
-
-// Update returns true if and only if 'current' is the highest value ever seen.
-func (hwm *HighWaterMark) Update(current int64) bool {
-	for {
-		old := atomic.LoadInt64((*int64)(hwm))
-		if current <= old {
-			return false
-		}
-		if atomic.CompareAndSwapInt64((*int64)(hwm), old, current) {
-			return true
-		}
-	}
-}
-
 // TransformFunc attempts to convert an object to another object for use with a watcher.
 type TransformFunc func(runtime.Object) (runtime.Object, error)
 
@@ -109,8 +91,8 @@ type etcdWatcher struct {
 	emit func(watch.Event)
 
 	// HighWaterMarks for performance debugging.
-	incomingHWM HighWaterMark
-	outgoingHWM HighWaterMark
+	incomingHWM storage.HighWaterMark
+	outgoingHWM storage.HighWaterMark
 
 	cache etcdCache
 }

pkg/storage/etcd/etcd_watcher_test.go

@@ -17,9 +17,7 @@ limitations under the License.
 package etcd
 
 import (
-	"math/rand"
 	rt "runtime"
-	"sync"
 	"testing"
 
 	"k8s.io/kubernetes/pkg/api"
@@ -557,34 +555,3 @@ func TestWatchPurposefulShutdown(t *testing.T) {
 		t.Errorf("Unexpected event from stopped watcher: %#v", event)
 	}
 }
-
-func TestHighWaterMark(t *testing.T) {
-	var h HighWaterMark
-
-	for i := int64(10); i < 20; i++ {
-		if !h.Update(i) {
-			t.Errorf("unexpected false for %v", i)
-		}
-		if h.Update(i - 1) {
-			t.Errorf("unexpected true for %v", i-1)
-		}
-	}
-
-	m := int64(0)
-	wg := sync.WaitGroup{}
-	for i := 0; i < 300; i++ {
-		wg.Add(1)
-		v := rand.Int63()
-		go func(v int64) {
-			defer wg.Done()
-			h.Update(v)
-		}(v)
-		if v > m {
-			m = v
-		}
-	}
-	wg.Wait()
-	if m != int64(h) {
-		t.Errorf("unexpected value, wanted %v, got %v", m, int64(h))
-	}
-}

pkg/storage/util.go

@@ -20,6 +20,7 @@ import (
 	"fmt"
 	"strconv"
 	"strings"
+	"sync/atomic"
 
 	"k8s.io/kubernetes/pkg/api/meta"
 	"k8s.io/kubernetes/pkg/api/validation/path"
@@ -149,3 +150,20 @@ func hasPathPrefix(s, pathPrefix string) bool {
 	}
 	return false
 }
+
+// HighWaterMark is a thread-safe object for tracking the maximum value seen
+// for some quantity.
+type HighWaterMark int64
+
+// Update returns true if and only if 'current' is the highest value ever seen.
+func (hwm *HighWaterMark) Update(current int64) bool {
+	for {
+		old := atomic.LoadInt64((*int64)(hwm))
+		if current <= old {
+			return false
+		}
+		if atomic.CompareAndSwapInt64((*int64)(hwm), old, current) {
+			return true
+		}
+	}
+}

pkg/storage/util_test.go

@@ -16,7 +16,11 @@ limitations under the License.
 
 package storage
 
-import "testing"
+import (
+	"math/rand"
+	"sync"
+	"testing"
+)
 
 func TestEtcdParseWatchResourceVersion(t *testing.T) {
 	testCases := []struct {
@@ -99,3 +103,34 @@ func TestHasPathPrefix(t *testing.T) {
 		}
 	}
 }
+
+func TestHighWaterMark(t *testing.T) {
+	var h HighWaterMark
+
+	for i := int64(10); i < 20; i++ {
+		if !h.Update(i) {
+			t.Errorf("unexpected false for %v", i)
+		}
+		if h.Update(i - 1) {
+			t.Errorf("unexpected true for %v", i-1)
+		}
+	}
+
+	m := int64(0)
+	wg := sync.WaitGroup{}
+	for i := 0; i < 300; i++ {
+		wg.Add(1)
+		v := rand.Int63()
+		go func(v int64) {
+			defer wg.Done()
+			h.Update(v)
+		}(v)
+		if v > m {
+			m = v
+		}
+	}
+	wg.Wait()
+	if m != int64(h) {
+		t.Errorf("unexpected value, wanted %v, got %v", m, int64(h))
+	}
+}