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Commit 3a36dfb3 authored by Oleg Shaldybin's avatar Oleg Shaldybin Committed by Oleg Shaldibin
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Minor selectHost optimization in scheduler

Instead of sorting hosts by score, find max score and choose one of the hosts with max score directly. Saves a little time on sorting and avoids extra copying of HostPriorityList entries. Test had to be updated as one of the test cases relied on having a stable order from pre-sorting.
parent 0b044158
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Showing with 56 additions and 59 deletions
plugin/pkg/scheduler/generic_scheduler.go
View file @ 3a36dfb3
......@@ -20,7 +20,6 @@ import (
"bytes"
"fmt"
"math/rand"
"sort"
"strings"
"sync"
......@@ -101,20 +100,31 @@ func (g *genericScheduler) Schedule(pod *api.Pod, nodeLister algorithm.NodeListe
return g.selectHost(priorityList)
}
// This method takes a prioritized list of nodes and sorts them in reverse order based on scores
// and then picks one randomly from the nodes that had the highest score
// selectHost takes a prioritized list of nodes and then picks one
// randomly from the nodes that had the highest score.
func (g *genericScheduler) selectHost(priorityList schedulerapi.HostPriorityList) (string, error) {
if len(priorityList) == 0 {
return "", fmt.Errorf("empty priorityList")
}
sort.Sort(sort.Reverse(priorityList))
hosts := getBestHosts(priorityList)
maxScore := priorityList[0].Score
// idx contains indices of elements with score == maxScore.
idx := []int{}
for i, entry := range priorityList {
if entry.Score > maxScore {
maxScore = entry.Score
idx = []int{i}
} else if entry.Score == maxScore {
idx = append(idx, i)
}
}
g.randomLock.Lock()
defer g.randomLock.Unlock()
ix := g.random.Int() % len(idx)
g.randomLock.Unlock()
ix := g.random.Int() % len(hosts)
return hosts[ix], nil
return priorityList[idx[ix]].Host, nil
}
// Filters the nodes to find the ones that fit based on the given predicate functions
......@@ -258,18 +268,6 @@ func PrioritizeNodes(pod *api.Pod, machinesToPods map[string][]*api.Pod, podList
return result, nil
}
func getBestHosts(list schedulerapi.HostPriorityList) []string {
result := []string{}
for _, hostEntry := range list {
if hostEntry.Score == list[0].Score {
result = append(result, hostEntry.Host)
} else {
break
}
}
return result
}
// EqualPriority is a prioritizer function that gives an equal weight of one to all nodes
func EqualPriority(_ *api.Pod, machinesToPods map[string][]*api.Pod, podLister algorithm.PodLister, nodeLister algorithm.NodeLister) (schedulerapi.HostPriorityList, error) {
nodes, err := nodeLister.List()
......
plugin/pkg/scheduler/generic_scheduler_test.go
View file @ 3a36dfb3
......@@ -166,14 +166,14 @@ func TestSelectHost(t *testing.T) {
func TestGenericScheduler(t *testing.T) {
tests := []struct {
name string
predicates map[string]algorithm.FitPredicate
prioritizers []algorithm.PriorityConfig
nodes []string
pod *api.Pod
pods []*api.Pod
expectedHost string
expectsErr bool
name string
predicates map[string]algorithm.FitPredicate
prioritizers []algorithm.PriorityConfig
nodes []string
pod *api.Pod
pods []*api.Pod
expectedHosts sets.String
expectsErr bool
}{
{
predicates: map[string]algorithm.FitPredicate{"false": falsePredicate},
......@@ -183,44 +183,43 @@ func TestGenericScheduler(t *testing.T) {
name: "test 1",
},
{
predicates: map[string]algorithm.FitPredicate{"true": truePredicate},
prioritizers: []algorithm.PriorityConfig{{Function: EqualPriority, Weight: 1}},
nodes: []string{"machine1", "machine2"},
// Random choice between both, the rand seeded above with zero, chooses "machine1"
expectedHost: "machine1",
name: "test 2",
predicates: map[string]algorithm.FitPredicate{"true": truePredicate},
prioritizers: []algorithm.PriorityConfig{{Function: EqualPriority, Weight: 1}},
nodes: []string{"machine1", "machine2"},
expectedHosts: sets.NewString("machine1", "machine2"),
name: "test 2",
},
{
// Fits on a machine where the pod ID matches the machine name
predicates: map[string]algorithm.FitPredicate{"matches": matchesPredicate},
prioritizers: []algorithm.PriorityConfig{{Function: EqualPriority, Weight: 1}},
nodes: []string{"machine1", "machine2"},
pod: &api.Pod{ObjectMeta: api.ObjectMeta{Name: "machine2"}},
expectedHost: "machine2",
name: "test 3",
predicates: map[string]algorithm.FitPredicate{"matches": matchesPredicate},
prioritizers: []algorithm.PriorityConfig{{Function: EqualPriority, Weight: 1}},
nodes: []string{"machine1", "machine2"},
pod: &api.Pod{ObjectMeta: api.ObjectMeta{Name: "machine2"}},
expectedHosts: sets.NewString("machine2"),
name: "test 3",
},
{
predicates: map[string]algorithm.FitPredicate{"true": truePredicate},
prioritizers: []algorithm.PriorityConfig{{Function: numericPriority, Weight: 1}},
nodes: []string{"3", "2", "1"},
expectedHost: "3",
name: "test 4",
predicates: map[string]algorithm.FitPredicate{"true": truePredicate},
prioritizers: []algorithm.PriorityConfig{{Function: numericPriority, Weight: 1}},
nodes: []string{"3", "2", "1"},
expectedHosts: sets.NewString("3"),
name: "test 4",
},
{
predicates: map[string]algorithm.FitPredicate{"matches": matchesPredicate},
prioritizers: []algorithm.PriorityConfig{{Function: numericPriority, Weight: 1}},
nodes: []string{"3", "2", "1"},
pod: &api.Pod{ObjectMeta: api.ObjectMeta{Name: "2"}},
expectedHost: "2",
name: "test 5",
predicates: map[string]algorithm.FitPredicate{"matches": matchesPredicate},
prioritizers: []algorithm.PriorityConfig{{Function: numericPriority, Weight: 1}},
nodes: []string{"3", "2", "1"},
pod: &api.Pod{ObjectMeta: api.ObjectMeta{Name: "2"}},
expectedHosts: sets.NewString("2"),
name: "test 5",
},
{
predicates: map[string]algorithm.FitPredicate{"true": truePredicate},
prioritizers: []algorithm.PriorityConfig{{Function: numericPriority, Weight: 1}, {Function: reverseNumericPriority, Weight: 2}},
nodes: []string{"3", "2", "1"},
pod: &api.Pod{ObjectMeta: api.ObjectMeta{Name: "2"}},
expectedHost: "1",
name: "test 6",
predicates: map[string]algorithm.FitPredicate{"true": truePredicate},
prioritizers: []algorithm.PriorityConfig{{Function: numericPriority, Weight: 1}, {Function: reverseNumericPriority, Weight: 2}},
nodes: []string{"3", "2", "1"},
pod: &api.Pod{ObjectMeta: api.ObjectMeta{Name: "2"}},
expectedHosts: sets.NewString("1"),
name: "test 6",
},
{
predicates: map[string]algorithm.FitPredicate{"true": truePredicate, "false": falsePredicate},
......@@ -266,8 +265,8 @@ func TestGenericScheduler(t *testing.T) {
if err != nil {
t.Errorf("Unexpected error: %v", err)
}
if test.expectedHost != machine {
t.Errorf("Failed : %s, Expected: %s, Saw: %s", test.name, test.expectedHost, machine)
if !test.expectedHosts.Has(machine) {
t.Errorf("Failed : %s, Expected: %s, Saw: %s", test.name, test.expectedHosts, machine)
}
}
}
......
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