Avoid creating NodeInfoMap from scratch on every scheduling.

plugin/pkg/scheduler/generic_scheduler.go

@@ -62,6 +62,8 @@ type genericScheduler struct {
 	pods              algorithm.PodLister
 	lastNodeIndexLock sync.Mutex
 	lastNodeIndex     uint64
+
+	cachedNodeInfoMap map[string]*schedulercache.NodeInfo
 }
 
 // Schedule tries to schedule the given pod to one of node in the node list.
@@ -85,13 +87,13 @@ func (g *genericScheduler) Schedule(pod *api.Pod, nodeLister algorithm.NodeListe
 	}
 
 	// Used for all fit and priority funcs.
-	nodeNameToInfo, err := g.cache.GetNodeNameToInfoMap()
+	err = g.cache.UpdateNodeNameToInfoMap(g.cachedNodeInfoMap)
 	if err != nil {
 		return "", err
 	}
 
 	trace.Step("Computing predicates")
-	filteredNodes, failedPredicateMap, err := findNodesThatFit(pod, nodeNameToInfo, g.predicates, nodes, g.extenders)
+	filteredNodes, failedPredicateMap, err := findNodesThatFit(pod, g.cachedNodeInfoMap, g.predicates, nodes, g.extenders)
 	if err != nil {
 		return "", err
 	}
@@ -104,7 +106,7 @@ func (g *genericScheduler) Schedule(pod *api.Pod, nodeLister algorithm.NodeListe
 	}
 
 	trace.Step("Prioritizing")
-	priorityList, err := PrioritizeNodes(pod, nodeNameToInfo, g.prioritizers, algorithm.FakeNodeLister(filteredNodes), g.extenders)
+	priorityList, err := PrioritizeNodes(pod, g.cachedNodeInfoMap, g.prioritizers, algorithm.FakeNodeLister(filteredNodes), g.extenders)
 	if err != nil {
 		return "", err
 	}
@@ -329,9 +331,10 @@ func EqualPriority(_ *api.Pod, nodeNameToInfo map[string]*schedulercache.NodeInf
 
 func NewGenericScheduler(cache schedulercache.Cache, predicates map[string]algorithm.FitPredicate, prioritizers []algorithm.PriorityConfig, extenders []algorithm.SchedulerExtender) algorithm.ScheduleAlgorithm {
 	return &genericScheduler{
-		cache:        cache,
-		predicates:   predicates,
-		prioritizers: prioritizers,
-		extenders:    extenders,
+		cache:             cache,
+		predicates:        predicates,
+		prioritizers:      prioritizers,
+		extenders:         extenders,
+		cachedNodeInfoMap: make(map[string]*schedulercache.NodeInfo),
 	}
 }

plugin/pkg/scheduler/schedulercache/cache.go

@@ -74,14 +74,20 @@ func newSchedulerCache(ttl, period time.Duration, stop <-chan struct{}) *schedul
 	}
 }
 
-func (cache *schedulerCache) GetNodeNameToInfoMap() (map[string]*NodeInfo, error) {
-	nodeNameToInfo := make(map[string]*NodeInfo)
+func (cache *schedulerCache) UpdateNodeNameToInfoMap(nodeNameToInfo map[string]*NodeInfo) error {
 	cache.mu.Lock()
 	defer cache.mu.Unlock()
 	for name, info := range cache.nodes {
-		nodeNameToInfo[name] = info.Clone()
+		if current, ok := nodeNameToInfo[name]; !ok || current.generation != info.generation {
+			nodeNameToInfo[name] = info.Clone()
+		}
+	}
+	for name := range nodeNameToInfo {
+		if _, ok := cache.nodes[name]; !ok {
+			delete(nodeNameToInfo, name)
+		}
 	}
-	return nodeNameToInfo, nil
+	return nil
 }
 
 func (cache *schedulerCache) List(selector labels.Selector) ([]*api.Pod, error) {

plugin/pkg/scheduler/schedulercache/cache_test.go

@@ -28,6 +28,16 @@ import (
 	priorityutil "k8s.io/kubernetes/plugin/pkg/scheduler/algorithm/priorities/util"
 )
 
+func deepEqualWithoutGeneration(t *testing.T, testcase int, actual, expected *NodeInfo) {
+	// Ignore generation field.
+	if actual != nil {
+		actual.generation = 0
+	}
+	if !reflect.DeepEqual(actual, expected) {
+		t.Errorf("#%d: node info get=%s, want=%s", testcase, actual, expected)
+	}
+}
+
 // TestAssumePodScheduled tests that after a pod is assumed, its information is aggregated
 // on node level.
 func TestAssumePodScheduled(t *testing.T) {
@@ -92,9 +102,7 @@ func TestAssumePodScheduled(t *testing.T) {
 			}
 		}
 		n := cache.nodes[nodeName]
-		if !reflect.DeepEqual(n, tt.wNodeInfo) {
-			t.Errorf("#%d: node info get=%s, want=%s", i, n, tt.wNodeInfo)
-		}
+		deepEqualWithoutGeneration(t, i, n, tt.wNodeInfo)
 	}
 }
 
@@ -154,9 +162,7 @@ func TestExpirePod(t *testing.T) {
 		// pods that have assumedTime + ttl < cleanupTime will get expired and removed
 		cache.cleanupAssumedPods(tt.cleanupTime)
 		n := cache.nodes[nodeName]
-		if !reflect.DeepEqual(n, tt.wNodeInfo) {
-			t.Errorf("#%d: node info get=%s, want=%s", i, n, tt.wNodeInfo)
-		}
+		deepEqualWithoutGeneration(t, i, n, tt.wNodeInfo)
 	}
 }
 
@@ -207,9 +213,7 @@ func TestAddPodWillConfirm(t *testing.T) {
 		cache.cleanupAssumedPods(now.Add(2 * ttl))
 		// check after expiration. confirmed pods shouldn't be expired.
 		n := cache.nodes[nodeName]
-		if !reflect.DeepEqual(n, tt.wNodeInfo) {
-			t.Errorf("#%d: node info get=%s, want=%s", i, n, tt.wNodeInfo)
-		}
+		deepEqualWithoutGeneration(t, i, n, tt.wNodeInfo)
 	}
 }
 
@@ -254,9 +258,7 @@ func TestAddPodAfterExpiration(t *testing.T) {
 		}
 		// check after expiration. confirmed pods shouldn't be expired.
 		n = cache.nodes[nodeName]
-		if !reflect.DeepEqual(n, tt.wNodeInfo) {
-			t.Errorf("#%d: node info get=%s, want=%s", i, n, tt.wNodeInfo)
-		}
+		deepEqualWithoutGeneration(t, i, n, tt.wNodeInfo)
 	}
 }
 
@@ -317,9 +319,7 @@ func TestUpdatePod(t *testing.T) {
 			}
 			// check after expiration. confirmed pods shouldn't be expired.
 			n := cache.nodes[nodeName]
-			if !reflect.DeepEqual(n, tt.wNodeInfo[i-1]) {
-				t.Errorf("#%d: node info get=%s, want=%s", i-1, n, tt.wNodeInfo)
-			}
+			deepEqualWithoutGeneration(t, i, n, tt.wNodeInfo[i-1])
 		}
 	}
 }
@@ -390,9 +390,7 @@ func TestExpireAddUpdatePod(t *testing.T) {
 			}
 			// check after expiration. confirmed pods shouldn't be expired.
 			n := cache.nodes[nodeName]
-			if !reflect.DeepEqual(n, tt.wNodeInfo[i-1]) {
-				t.Errorf("#%d: node info get=%s, want=%s", i-1, n, tt.wNodeInfo)
-			}
+			deepEqualWithoutGeneration(t, i, n, tt.wNodeInfo[i-1])
 		}
 	}
 }
@@ -426,9 +424,7 @@ func TestRemovePod(t *testing.T) {
 			t.Fatalf("AddPod failed: %v", err)
 		}
 		n := cache.nodes[nodeName]
-		if !reflect.DeepEqual(n, tt.wNodeInfo) {
-			t.Errorf("#%d: node info get=%s, want=%s", i, n, tt.wNodeInfo)
-		}
+		deepEqualWithoutGeneration(t, i, n, tt.wNodeInfo)
 
 		if err := cache.RemovePod(tt.pod); err != nil {
 			t.Fatalf("RemovePod failed: %v", err)
@@ -441,14 +437,6 @@ func TestRemovePod(t *testing.T) {
 	}
 }
 
-func BenchmarkGetNodeNameToInfoMap1kNodes30kPods(b *testing.B) {
-	cache := setupCacheOf1kNodes30kPods(b)
-	b.ResetTimer()
-	for n := 0; n < b.N; n++ {
-		cache.GetNodeNameToInfoMap()
-	}
-}
-
 func BenchmarkList1kNodes30kPods(b *testing.B) {
 	cache := setupCacheOf1kNodes30kPods(b)
 	b.ResetTimer()

plugin/pkg/scheduler/schedulercache/interface.go

@@ -80,9 +80,10 @@ type Cache interface {
 	// RemoveNode removes overall information about node.
 	RemoveNode(node *api.Node) error
 
-	// GetNodeNameToInfoMap returns a map of node names to node info. The node info contains
-	// aggregated information of pods scheduled (including assumed to be) on this node.
-	GetNodeNameToInfoMap() (map[string]*NodeInfo, error)
+	// UpdateNodeNameToInfoMap updates the passed infoMap to the current contents of Cache.
+	// The node info contains aggregated information of pods scheduled (including assumed to be)
+	// on this node.
+	UpdateNodeNameToInfoMap(infoMap map[string]*NodeInfo) error
 
 	// List lists all cached pods (including assumed ones).
 	List(labels.Selector) ([]*api.Pod, error)

plugin/pkg/scheduler/schedulercache/node_info.go

@@ -39,6 +39,10 @@ type NodeInfo struct {
 	requestedResource *Resource
 	pods              []*api.Pod
 	nonzeroRequest    *Resource
+
+	// Whenever NodeInfo changes, generation is bumped.
+	// This is used to avoid cloning it if the object didn't change.
+	generation int64
 }
 
 // Resource is a collection of compute resource.
@@ -55,6 +59,7 @@ func NewNodeInfo(pods ...*api.Pod) *NodeInfo {
 	ni := &NodeInfo{
 		requestedResource: &Resource{},
 		nonzeroRequest:    &Resource{},
+		generation:        0,
 	}
 	for _, pod := range pods {
 		ni.addPod(pod)
@@ -101,6 +106,7 @@ func (n *NodeInfo) Clone() *NodeInfo {
 		requestedResource: &(*n.requestedResource),
 		nonzeroRequest:    &(*n.nonzeroRequest),
 		pods:              pods,
+		generation:        n.generation,
 	}
 	return clone
 }
@@ -123,6 +129,7 @@ func (n *NodeInfo) addPod(pod *api.Pod) {
 	n.nonzeroRequest.MilliCPU += non0_cpu
 	n.nonzeroRequest.Memory += non0_mem
 	n.pods = append(n.pods, pod)
+	n.generation++
 }
 
 // removePod subtracts pod information to this NodeInfo.
@@ -149,6 +156,7 @@ func (n *NodeInfo) removePod(pod *api.Pod) error {
 			n.requestedResource.NvidiaGPU -= nvidia_gpu
 			n.nonzeroRequest.MilliCPU -= non0_cpu
 			n.nonzeroRequest.Memory -= non0_mem
+			n.generation++
 			return nil
 		}
 	}
@@ -173,6 +181,7 @@ func calculateResource(pod *api.Pod) (cpu int64, mem int64, nvidia_gpu int64, no
 // Sets the overall node information.
 func (n *NodeInfo) SetNode(node *api.Node) error {
 	n.node = node
+	n.generation++
 	return nil
 }
 
@@ -183,6 +192,7 @@ func (n *NodeInfo) RemoveNode(node *api.Node) error {
 	// and thus can potentially be observed later, even though they happened before
 	// node removal. This is handled correctly in cache.go file.
 	n.node = nil
+	n.generation++
 	return nil
 }
 

plugin/pkg/scheduler/testing/fake_cache.go

@@ -44,8 +44,8 @@ func (f *FakeCache) UpdateNode(oldNode, newNode *api.Node) error { return nil }
 
 func (f *FakeCache) RemoveNode(node *api.Node) error { return nil }
 
-func (f *FakeCache) GetNodeNameToInfoMap() (map[string]*schedulercache.NodeInfo, error) {
-	return nil, nil
+func (f *FakeCache) UpdateNodeNameToInfoMap(infoMap map[string]*schedulercache.NodeInfo) error {
+	return nil
 }
 
 func (f *FakeCache) List(s labels.Selector) ([]*api.Pod, error) { return nil, nil }

plugin/pkg/scheduler/testing/pods_to_cache.go

@@ -41,8 +41,9 @@ func (p PodsToCache) UpdateNode(oldNode, newNode *api.Node) error { return nil }
 
 func (p PodsToCache) RemoveNode(node *api.Node) error { return nil }
 
-func (p PodsToCache) GetNodeNameToInfoMap() (map[string]*schedulercache.NodeInfo, error) {
-	return schedulercache.CreateNodeNameToInfoMap(p), nil
+func (p PodsToCache) UpdateNodeNameToInfoMap(infoMap map[string]*schedulercache.NodeInfo) error {
+	infoMap = schedulercache.CreateNodeNameToInfoMap(p)
+	return nil
 }
 
 func (p PodsToCache) List(s labels.Selector) (selected []*api.Pod, err error) {