From 6d89279115a1a06817450753029510ed74ea6883 Mon Sep 17 00:00:00 2001
From: Wei Huang <wei.huang1@ibm.com>
Date: Sat, 13 Apr 2019 09:09:22 -0700
Subject: [PATCH] Revert "scheduler: performance improvement on PodAffinity"

This reverts commit 28730919a69d0a1518853fcc91ba54231919f7ed.
---
 .../algorithm/priorities/interpod_affinity.go | 43 ++++++++++---------
 1 file changed, 23 insertions(+), 20 deletions(-)

diff --git a/pkg/scheduler/algorithm/priorities/interpod_affinity.go b/pkg/scheduler/algorithm/priorities/interpod_affinity.go
index 2872dd9ac2..62540a5941 100644
--- a/pkg/scheduler/algorithm/priorities/interpod_affinity.go
+++ b/pkg/scheduler/algorithm/priorities/interpod_affinity.go
@@ -19,7 +19,6 @@ package priorities
 import (
 	"context"
 	"sync"
-	"sync/atomic"
 
 	"k8s.io/api/core/v1"
 	apierrors "k8s.io/apimachinery/pkg/api/errors"
@@ -64,7 +63,7 @@ type podAffinityPriorityMap struct {
 	nodes []*v1.Node
 	// counts store the mapping from node name to so-far computed score of
 	// the node.
-	counts map[string]*int64
+	counts map[string]float64
 	// The first error that we faced.
 	firstError error
 }
@@ -72,7 +71,7 @@ type podAffinityPriorityMap struct {
 func newPodAffinityPriorityMap(nodes []*v1.Node) *podAffinityPriorityMap {
 	return &podAffinityPriorityMap{
 		nodes:  nodes,
-		counts: make(map[string]*int64, len(nodes)),
+		counts: make(map[string]float64, len(nodes)),
 	}
 }
 
@@ -84,7 +83,7 @@ func (p *podAffinityPriorityMap) setError(err error) {
 	}
 }
 
-func (p *podAffinityPriorityMap) processTerm(term *v1.PodAffinityTerm, podDefiningAffinityTerm, podToCheck *v1.Pod, fixedNode *v1.Node, weight int64) {
+func (p *podAffinityPriorityMap) processTerm(term *v1.PodAffinityTerm, podDefiningAffinityTerm, podToCheck *v1.Pod, fixedNode *v1.Node, weight float64) {
 	namespaces := priorityutil.GetNamespacesFromPodAffinityTerm(podDefiningAffinityTerm, term)
 	selector, err := metav1.LabelSelectorAsSelector(term.LabelSelector)
 	if err != nil {
@@ -93,18 +92,22 @@ func (p *podAffinityPriorityMap) processTerm(term *v1.PodAffinityTerm, podDefini
 	}
 	match := priorityutil.PodMatchesTermsNamespaceAndSelector(podToCheck, namespaces, selector)
 	if match {
-		for _, node := range p.nodes {
-			if priorityutil.NodesHaveSameTopologyKey(node, fixedNode, term.TopologyKey) {
-				atomic.AddInt64(p.counts[node.Name], weight)
+		func() {
+			p.Lock()
+			defer p.Unlock()
+			for _, node := range p.nodes {
+				if priorityutil.NodesHaveSameTopologyKey(node, fixedNode, term.TopologyKey) {
+					p.counts[node.Name] += weight
+				}
 			}
-		}
+		}()
 	}
 }
 
 func (p *podAffinityPriorityMap) processTerms(terms []v1.WeightedPodAffinityTerm, podDefiningAffinityTerm, podToCheck *v1.Pod, fixedNode *v1.Node, multiplier int) {
 	for i := range terms {
 		term := &terms[i]
-		p.processTerm(&term.PodAffinityTerm, podDefiningAffinityTerm, podToCheck, fixedNode, int64(term.Weight*int32(multiplier)))
+		p.processTerm(&term.PodAffinityTerm, podDefiningAffinityTerm, podToCheck, fixedNode, float64(term.Weight*int32(multiplier)))
 	}
 }
 
@@ -118,17 +121,17 @@ func (ipa *InterPodAffinity) CalculateInterPodAffinityPriority(pod *v1.Pod, node
 	hasAffinityConstraints := affinity != nil && affinity.PodAffinity != nil
 	hasAntiAffinityConstraints := affinity != nil && affinity.PodAntiAffinity != nil
 
-	// priorityMap stores the mapping from node name to so-far computed score of
-	// the node.
-	pm := newPodAffinityPriorityMap(nodes)
 	allNodeNames := make([]string, 0, len(nodeNameToInfo))
 	for name := range nodeNameToInfo {
 		allNodeNames = append(allNodeNames, name)
-		pm.counts[name] = new(int64)
 	}
 
 	// convert the topology key based weights to the node name based weights
-	var maxCount, minCount int64
+	var maxCount float64
+	var minCount float64
+	// priorityMap stores the mapping from node name to so-far computed score of
+	// the node.
+	pm := newPodAffinityPriorityMap(nodes)
 
 	processPod := func(existingPod *v1.Pod) error {
 		existingPodNode, err := ipa.info.GetNodeInfo(existingPod.Spec.NodeName)
@@ -169,7 +172,7 @@ func (ipa *InterPodAffinity) CalculateInterPodAffinityPriority(pod *v1.Pod, node
 				//	terms = append(terms, existingPodAffinity.PodAffinity.RequiredDuringSchedulingRequiredDuringExecution...)
 				//}
 				for _, term := range terms {
-					pm.processTerm(&term, existingPod, pod, existingPodNode, int64(ipa.hardPodAffinityWeight))
+					pm.processTerm(&term, existingPod, pod, existingPodNode, float64(ipa.hardPodAffinityWeight))
 				}
 			}
 			// For every soft pod affinity term of <existingPod>, if <pod> matches the term,
@@ -214,11 +217,11 @@ func (ipa *InterPodAffinity) CalculateInterPodAffinityPriority(pod *v1.Pod, node
 	}
 
 	for _, node := range nodes {
-		if *pm.counts[node.Name] > maxCount {
-			maxCount = *pm.counts[node.Name]
+		if pm.counts[node.Name] > maxCount {
+			maxCount = pm.counts[node.Name]
 		}
-		if *pm.counts[node.Name] < minCount {
-			minCount = *pm.counts[node.Name]
+		if pm.counts[node.Name] < minCount {
+			minCount = pm.counts[node.Name]
 		}
 	}
 
@@ -227,7 +230,7 @@ func (ipa *InterPodAffinity) CalculateInterPodAffinityPriority(pod *v1.Pod, node
 	for _, node := range nodes {
 		fScore := float64(0)
 		if (maxCount - minCount) > 0 {
-			fScore = float64(schedulerapi.MaxPriority) * (float64(*pm.counts[node.Name]-minCount) / float64(maxCount-minCount))
+			fScore = float64(schedulerapi.MaxPriority) * ((pm.counts[node.Name] - minCount) / (maxCount - minCount))
 		}
 		result = append(result, schedulerapi.HostPriority{Host: node.Name, Score: int(fScore)})
 		if klog.V(10) {