Cache AllowedPodNumber to avoid conversions.

plugin/pkg/scheduler/algorithm/predicates/predicates.go

@@ -472,11 +472,10 @@ func PodFitsResources(pod *api.Pod, meta interface{}, nodeInfo *schedulercache.N
 	if node == nil {
 		return false, fmt.Errorf("node not found")
 	}
-	allocatable := node.Status.Allocatable
+	allowedPodNumber := nodeInfo.AllowedPodNumber()
-	allowedPodNumber := allocatable.Pods().Value()
+	if len(nodeInfo.Pods())+1 > allowedPodNumber {
-	if int64(len(nodeInfo.Pods()))+1 > allowedPodNumber {
 		return false,
-			newInsufficientResourceError(podCountResourceName, 1, int64(len(nodeInfo.Pods())), allowedPodNumber)
+			newInsufficientResourceError(podCountResourceName, 1, int64(len(nodeInfo.Pods())), int64(allowedPodNumber))
 	}
 
 	var podRequest *resourceRequest
@@ -491,6 +490,7 @@ func PodFitsResources(pod *api.Pod, meta interface{}, nodeInfo *schedulercache.N
 		return true, nil
 	}
 
+	allocatable := node.Status.Allocatable
 	totalMilliCPU := allocatable.Cpu().MilliValue()
 	totalMemory := allocatable.Memory().Value()
 	totalNvidiaGPU := allocatable.NvidiaGPU().Value()
@@ -507,8 +507,12 @@ func PodFitsResources(pod *api.Pod, meta interface{}, nodeInfo *schedulercache.N
 		return false,
 			newInsufficientResourceError(nvidiaGpuResourceName, podRequest.nvidiaGPU, nodeInfo.RequestedResource().NvidiaGPU, totalNvidiaGPU)
 	}
-	glog.V(10).Infof("Schedule Pod %+v on Node %+v is allowed, Node is running only %v out of %v Pods.",
+	if glog.V(10) {
+		// We explicitly don't do glog.V(10).Infof() to avoid computing all the parameters if this is
+		// not logged. There is visible performance gain from it.
+		glog.Infof("Schedule Pod %+v on Node %+v is allowed, Node is running only %v out of %v Pods.",
 			podName(pod), node.Name, len(nodeInfo.Pods()), allowedPodNumber)
+	}
 	return true, nil
 }
 

plugin/pkg/scheduler/schedulercache/node_info.go

@@ -39,6 +39,9 @@ type NodeInfo struct {
 	requestedResource *Resource
 	pods              []*api.Pod
 	nonzeroRequest    *Resource
+	// We store allowedPodNumber (which is Node.Status.Allocatable.Pods().Value())
+	// explicitly as int, to avoid conversions and improve performance.
+	allowedPodNumber int
 
 	// Whenever NodeInfo changes, generation is bumped.
 	// This is used to avoid cloning it if the object didn't change.
@@ -59,6 +62,7 @@ func NewNodeInfo(pods ...*api.Pod) *NodeInfo {
 	ni := &NodeInfo{
 		requestedResource: &Resource{},
 		nonzeroRequest:    &Resource{},
+		allowedPodNumber:  0,
 		generation:        0,
 	}
 	for _, pod := range pods {
@@ -83,6 +87,13 @@ func (n *NodeInfo) Pods() []*api.Pod {
 	return n.pods
 }
 
+func (n *NodeInfo) AllowedPodNumber() int {
+	if n == nil {
+		return 0
+	}
+	return n.allowedPodNumber
+}
+
 // RequestedResource returns aggregated resource request of pods on this node.
 func (n *NodeInfo) RequestedResource() Resource {
 	if n == nil {
@@ -105,6 +116,7 @@ func (n *NodeInfo) Clone() *NodeInfo {
 		node:              n.node,
 		requestedResource: &(*n.requestedResource),
 		nonzeroRequest:    &(*n.nonzeroRequest),
+		allowedPodNumber:  n.allowedPodNumber,
 		pods:              pods,
 		generation:        n.generation,
 	}
@@ -181,6 +193,7 @@ 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.allowedPodNumber = int(node.Status.Allocatable.Pods().Value())
 	n.generation++
 	return nil
 }
@@ -192,6 +205,7 @@ 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.allowedPodNumber = 0
 	n.generation++
 	return nil
 }