Parallel iteration

parallel.diff

diff --git a/pkg/scheduler/algorithm/priorities/even_pods_spread.go b/pkg/scheduler/algorithm/priorities/even_pods_spread.go
index 31d84c6727..0cbd1b908a 100644
--- a/pkg/scheduler/algorithm/priorities/even_pods_spread.go
+++ b/pkg/scheduler/algorithm/priorities/even_pods_spread.go
@@ -38,14 +38,14 @@ type topologyPair struct {
 
 type topologySpreadConstraintsMap struct {
 	// nodeNameToPodCounts is keyed with node name, and valued with the number of matching pods.
-	nodeNameToPodCounts map[string]int64
+	nodeNameToPodCounts map[string]*int64
 	// topologyPairToPodCounts is keyed with topologyPair, and valued with the number of matching pods.
 	topologyPairToPodCounts map[topologyPair]*int64
 }
 
 func newTopologySpreadConstraintsMap() *topologySpreadConstraintsMap {
 	return &topologySpreadConstraintsMap{
-		nodeNameToPodCounts:     make(map[string]int64),
+		nodeNameToPodCounts:     make(map[string]*int64),
 		topologyPairToPodCounts: make(map[topologyPair]*int64),
 	}
 }
@@ -67,7 +67,7 @@ func (t *topologySpreadConstraintsMap) initialize(pod *v1.Pod, nodes []*v1.Node)
 				t.topologyPairToPodCounts[pair] = new(int64)
 			}
 		}
-		t.nodeNameToPodCounts[node.Name] = 0
+		t.nodeNameToPodCounts[node.Name] = new(int64)
 		// For those nodes which don't have all required topologyKeys present, it's intentional to keep
 		// those entries absent in nodeNameToPodCounts, so that we're able to score them to 0 afterwards.
 	}
@@ -144,9 +144,10 @@ func CalculateEvenPodsSpreadPriority(pod *v1.Pod, nodeNameToInfo map[string]*sch
 	var minCount int64 = math.MaxInt64
 	// <total> sums up the number of matching pods on each qualified topology pair
 	var total int64
-	for _, node := range nodes {
-		if _, ok := t.nodeNameToPodCounts[node.Name]; !ok {
-			continue
+	processCandidateNode := func(i int) {
+		node := nodes[i]
+		if t.nodeNameToPodCounts[node.Name] == nil {
+			return
 		}
 
 		// For each present <pair>, current node gets a credit of <matchSum>.
@@ -155,14 +156,25 @@ func CalculateEvenPodsSpreadPriority(pod *v1.Pod, nodeNameToInfo map[string]*sch
 			if tpVal, ok := node.Labels[constraint.TopologyKey]; ok {
 				pair := topologyPair{key: constraint.TopologyKey, value: tpVal}
 				matchSum := atomic.LoadInt64(t.topologyPairToPodCounts[pair])
-				t.nodeNameToPodCounts[node.Name] += matchSum
+				atomic.AddInt64(t.nodeNameToPodCounts[node.Name], matchSum)
 				atomic.AddInt64(&total, matchSum)
 			}
 		}
-		if t.nodeNameToPodCounts[node.Name] < minCount {
-			minCount = t.nodeNameToPodCounts[node.Name]
+		// if t.nodeNameToPodCounts[node.Name] < minCount {
+		// 	minCount = t.nodeNameToPodCounts[node.Name]
+		// }
+		for {
+			swapped := true
+			_minCount := atomic.LoadInt64(&minCount)
+			if *t.nodeNameToPodCounts[node.Name] < _minCount {
+				swapped = swapped && atomic.CompareAndSwapInt64(&minCount, _minCount, *t.nodeNameToPodCounts[node.Name])
+			}
+			if swapped {
+				return
+			}
 		}
 	}
+	workqueue.ParallelizeUntil(ctx, 16, len(nodes), processCandidateNode)
 
 	// calculate final priority score for each node
 	// TODO(Huang-Wei): in alpha version, we keep the formula as simple as possible.
@@ -189,7 +201,7 @@ func CalculateEvenPodsSpreadPriority(pod *v1.Pod, nodeNameToInfo map[string]*sch
 			result[i].Score = schedulerapi.MaxPriority
 			continue
 		}
-		fScore := float64(schedulerapi.MaxPriority) * (float64(total-t.nodeNameToPodCounts[node.Name]) / float64(maxMinDiff))
+		fScore := float64(schedulerapi.MaxPriority) * (float64(total-*t.nodeNameToPodCounts[node.Name]) / float64(maxMinDiff))
 		result[i].Score = int(fScore)
 	}
 
diff --git a/pkg/scheduler/algorithm/priorities/even_pods_spread_test.go b/pkg/scheduler/algorithm/priorities/even_pods_spread_test.go
index b7da0dbe69..fdc2fdd625 100644
--- a/pkg/scheduler/algorithm/priorities/even_pods_spread_test.go
+++ b/pkg/scheduler/algorithm/priorities/even_pods_spread_test.go
@@ -32,7 +32,7 @@ func Test_topologySpreadConstraintsMap_initialize(t *testing.T) {
 		name                string
 		pod                 *v1.Pod
 		nodes               []*v1.Node
-		wantNodeNameMap     map[string]int64
+		wantNodeNameMap     map[string]*int64
 		wantTopologyPairMap map[topologyPair]*int64
 	}{
 		{
@@ -46,10 +46,10 @@ func Test_topologySpreadConstraintsMap_initialize(t *testing.T) {
 				st.MakeNode().Name("node-b").Label("zone", "zone1").Label("node", "node-b").Obj(),
 				st.MakeNode().Name("node-x").Label("zone", "zone2").Label("node", "node-x").Obj(),
 			},
-			wantNodeNameMap: map[string]int64{
-				"node-a": 0,
-				"node-b": 0,
-				"node-x": 0,
+			wantNodeNameMap: map[string]*int64{
+				"node-a": new(int64),
+				"node-b": new(int64),
+				"node-x": new(int64),
 			},
 			wantTopologyPairMap: map[topologyPair]*int64{
 				{key: "zone", value: "zone1"}:  new(int64),
@@ -70,9 +70,9 @@ func Test_topologySpreadConstraintsMap_initialize(t *testing.T) {
 				st.MakeNode().Name("node-b").Label("zone", "zone1").Label("node", "node-b").Obj(),
 				st.MakeNode().Name("node-x").Label("node", "node-x").Obj(),
 			},
-			wantNodeNameMap: map[string]int64{
-				"node-a": 0,
-				"node-b": 0,
+			wantNodeNameMap: map[string]*int64{
+				"node-a": new(int64),
+				"node-b": new(int64),
 			},
 			wantTopologyPairMap: map[topologyPair]*int64{
 				{key: "zone", value: "zone1"}:  new(int64),