mirror of
https://github.com/k3s-io/kubernetes.git
synced 2025-07-23 19:56:01 +00:00
Merge pull request #83665 from mars1024/feat/shuffle-sharding
shuffle sharding package for priority and fairness
This commit is contained in:
Kubernetes Prow Robot
GitHub
commit
cd274ff270
@ -44,6 +44,7 @@ filegroup(
|
||||
"//staging/src/k8s.io/apiserver/pkg/util/flushwriter:all-srcs",
|
||||
"//staging/src/k8s.io/apiserver/pkg/util/openapi:all-srcs",
|
||||
"//staging/src/k8s.io/apiserver/pkg/util/proxy:all-srcs",
|
||||
"//staging/src/k8s.io/apiserver/pkg/util/shufflesharding:all-srcs",
|
||||
"//staging/src/k8s.io/apiserver/pkg/util/term:all-srcs",
|
||||
"//staging/src/k8s.io/apiserver/pkg/util/webhook:all-srcs",
|
||||
"//staging/src/k8s.io/apiserver/pkg/util/wsstream:all-srcs",
|
||||
|
||||
29
staging/src/k8s.io/apiserver/pkg/util/shufflesharding/BUILD
Normal file
29
staging/src/k8s.io/apiserver/pkg/util/shufflesharding/BUILD
Normal file
@ -0,0 +1,29 @@
|
||||
load("@io_bazel_rules_go//go:def.bzl", "go_library", "go_test")
|
||||
|
||||
go_library(
|
||||
name = "go_default_library",
|
||||
srcs = ["shufflesharding.go"],
|
||||
importmap = "k8s.io/kubernetes/vendor/k8s.io/apiserver/pkg/util/shufflesharding",
|
||||
importpath = "k8s.io/apiserver/pkg/util/shufflesharding",
|
||||
visibility = ["//visibility:public"],
|
||||
)
|
||||
|
||||
go_test(
|
||||
name = "go_default_test",
|
||||
srcs = ["shufflesharding_test.go"],
|
||||
embed = [":go_default_library"],
|
||||
)
|
||||
|
||||
filegroup(
|
||||
name = "package-srcs",
|
||||
srcs = glob(["**"]),
|
||||
tags = ["automanaged"],
|
||||
visibility = ["//visibility:private"],
|
||||
)
|
||||
|
||||
filegroup(
|
||||
name = "all-srcs",
|
||||
srcs = [":package-srcs"],
|
||||
tags = ["automanaged"],
|
||||
visibility = ["//visibility:public"],
|
||||
)
|
||||
@ -0,0 +1,107 @@
|
||||
/*
|
||||
Copyright 2019 The Kubernetes Authors.
|
||||
|
||||
Licensed under the Apache License, Version 2.0 (the "License");
|
||||
you may not use this file except in compliance with the License.
|
||||
You may obtain a copy of the License at
|
||||
|
||||
http://www.apache.org/licenses/LICENSE-2.0
|
||||
|
||||
Unless required by applicable law or agreed to in writing, software
|
||||
distributed under the License is distributed on an "AS IS" BASIS,
|
||||
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
||||
See the License for the specific language governing permissions and
|
||||
limitations under the License.
|
||||
*/
|
||||
|
||||
package shufflesharding
|
||||
|
||||
import (
|
||||
"fmt"
|
||||
"math"
|
||||
)
|
||||
|
||||
// MaxHashBits is the max bit length which can be used from hash value.
|
||||
// If we use all bits of hash value, the critical(last) card shuffled by
|
||||
// Dealer will be uneven to 2:3 (first half:second half) at most,
|
||||
// in order to reduce this unevenness to 32:33, we set MaxHashBits to 60 here.
|
||||
const MaxHashBits = 60
|
||||
|
||||
// RequiredEntropyBits makes a quick and slightly conservative estimate of the number
|
||||
// of bits of hash value that are consumed in shuffle sharding a deck of the given size
|
||||
// to a hand of the given size. The result is meaningful only if
|
||||
// 1 <= handSize <= deckSize <= 1<<26.
|
||||
func RequiredEntropyBits(deckSize, handSize int) int {
|
||||
return int(math.Ceil(math.Log2(float64(deckSize)) * float64(handSize)))
|
||||
}
|
||||
|
||||
// Dealer contains some necessary parameters and provides some methods for shuffle sharding.
|
||||
// Dealer is thread-safe.
|
||||
type Dealer struct {
|
||||
deckSize int
|
||||
handSize int
|
||||
}
|
||||
|
||||
// NewDealer will create a Dealer with the given deckSize and handSize, will return error when
|
||||
// deckSize or handSize is invalid as below.
|
||||
// 1. deckSize or handSize is not positive
|
||||
// 2. handSize is greater than deckSize
|
||||
// 3. deckSize is impractically large (greater than 1<<26)
|
||||
// 4. required entropy bits of deckSize and handSize is greater than MaxHashBits
|
||||
func NewDealer(deckSize, handSize int) (*Dealer, error) {
|
||||
if deckSize <= 0 || handSize <= 0 {
|
||||
return nil, fmt.Errorf("deckSize %d or handSize %d is not positive", deckSize, handSize)
|
||||
}
|
||||
if handSize > deckSize {
|
||||
return nil, fmt.Errorf("handSize %d is greater than deckSize %d", handSize, deckSize)
|
||||
}
|
||||
if deckSize > 1<<26 {
|
||||
return nil, fmt.Errorf("deckSize %d is impractically large", deckSize)
|
||||
}
|
||||
if RequiredEntropyBits(deckSize, handSize) > MaxHashBits {
|
||||
return nil, fmt.Errorf("required entropy bits of deckSize %d and handSize %d is greater than %d", deckSize, handSize, MaxHashBits)
|
||||
}
|
||||
|
||||
return &Dealer{
|
||||
deckSize: deckSize,
|
||||
handSize: handSize,
|
||||
}, nil
|
||||
}
|
||||
|
||||
// Deal shuffles a card deck and deals a hand of cards, using the given hashValue as the source of entropy.
|
||||
// The deck size and hand size are properties of the Dealer.
|
||||
// This function synchronously makes sequential calls to pick, one for each dealt card.
|
||||
// Each card is identified by an integer in the range [0, deckSize).
|
||||
// For example, for deckSize=128 and handSize=4 this function might call pick(14); pick(73); pick(119); pick(26).
|
||||
func (d *Dealer) Deal(hashValue uint64, pick func(int)) {
|
||||
// 15 is the largest possible value of handSize
|
||||
var remainders [15]int
|
||||
|
||||
for i := 0; i < d.handSize; i++ {
|
||||
hashValueNext := hashValue / uint64(d.deckSize-i)
|
||||
remainders[i] = int(hashValue - uint64(d.deckSize-i)*hashValueNext)
|
||||
hashValue = hashValueNext
|
||||
}
|
||||
|
||||
for i := 0; i < d.handSize; i++ {
|
||||
card := remainders[i]
|
||||
for j := i; j > 0; j-- {
|
||||
if card >= remainders[j-1] {
|
||||
card++
|
||||
}
|
||||
}
|
||||
pick(card)
|
||||
}
|
||||
}
|
||||
|
||||
// DealIntoHand shuffles and deals according to the Dealer's parameters,
|
||||
// using the given hashValue as the source of entropy and then
|
||||
// returns the dealt cards as a slice of `int`.
|
||||
// If `hand` has the correct length as Dealer's handSize, it will be used as-is and no allocations will be made.
|
||||
// If `hand` is nil or too small, it will be extended (performing an allocation).
|
||||
// If `hand` is too large, a sub-slice will be returned.
|
||||
func (d *Dealer) DealIntoHand(hashValue uint64, hand []int) []int {
|
||||
h := hand[:0]
|
||||
d.Deal(hashValue, func(card int) { h = append(h, card) })
|
||||
return h
|
||||
}
|
||||
@ -0,0 +1,318 @@
|
||||
/*
|
||||
Copyright 2019 The Kubernetes Authors.
|
||||
|
||||
Licensed under the Apache License, Version 2.0 (the "License");
|
||||
you may not use this file except in compliance with the License.
|
||||
You may obtain a copy of the License at
|
||||
|
||||
http://www.apache.org/licenses/LICENSE-2.0
|
||||
|
||||
Unless required by applicable law or agreed to in writing, software
|
||||
distributed under the License is distributed on an "AS IS" BASIS,
|
||||
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
||||
See the License for the specific language governing permissions and
|
||||
limitations under the License.
|
||||
*/
|
||||
|
||||
package shufflesharding
|
||||
|
||||
import (
|
||||
"fmt"
|
||||
"math"
|
||||
"math/rand"
|
||||
"reflect"
|
||||
"sort"
|
||||
"testing"
|
||||
)
|
||||
|
||||
func TestRequiredEntropyBits(t *testing.T) {
|
||||
tests := []struct {
|
||||
name string
|
||||
deckSize int
|
||||
handSize int
|
||||
expectedBits int
|
||||
}{
|
||||
{
|
||||
"deckSize: 1024 handSize: 6",
|
||||
1024,
|
||||
6,
|
||||
60,
|
||||
},
|
||||
{
|
||||
"deckSize: 512 handSize: 8",
|
||||
512,
|
||||
8,
|
||||
72,
|
||||
},
|
||||
}
|
||||
|
||||
for _, test := range tests {
|
||||
bits := RequiredEntropyBits(test.deckSize, test.handSize)
|
||||
if bits != test.expectedBits {
|
||||
t.Errorf("test %s fails: expected %v but got %v", test.name, test.expectedBits, bits)
|
||||
return
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
func TestNewDealer(t *testing.T) {
|
||||
tests := []struct {
|
||||
name string
|
||||
deckSize int
|
||||
handSize int
|
||||
err error
|
||||
}{
|
||||
{
|
||||
"deckSize <= 0",
|
||||
-100,
|
||||
8,
|
||||
fmt.Errorf("deckSize -100 or handSize 8 is not positive"),
|
||||
},
|
||||
{
|
||||
"handSize <= 0",
|
||||
100,
|
||||
0,
|
||||
fmt.Errorf("deckSize 100 or handSize 0 is not positive"),
|
||||
},
|
||||
{
|
||||
"handSize is greater than deckSize",
|
||||
100,
|
||||
101,
|
||||
fmt.Errorf("handSize 101 is greater than deckSize 100"),
|
||||
},
|
||||
{
|
||||
"deckSize is impractically large",
|
||||
1 << 27,
|
||||
2,
|
||||
fmt.Errorf("deckSize 134217728 is impractically large"),
|
||||
},
|
||||
{
|
||||
"required entropy bits is greater than MaxHashBits",
|
||||
512,
|
||||
8,
|
||||
fmt.Errorf("required entropy bits of deckSize 512 and handSize 8 is greater than 60"),
|
||||
},
|
||||
{
|
||||
"deckSize: 1024 handSize: 6",
|
||||
1024,
|
||||
6,
|
||||
nil,
|
||||
},
|
||||
}
|
||||
for _, test := range tests {
|
||||
t.Run(test.name, func(t *testing.T) {
|
||||
_, err := NewDealer(test.deckSize, test.handSize)
|
||||
if !reflect.DeepEqual(err, test.err) {
|
||||
t.Errorf("test %s fails: expected %v but got %v", test.name, test.err, err)
|
||||
return
|
||||
}
|
||||
})
|
||||
}
|
||||
}
|
||||
|
||||
func TestCardDuplication(t *testing.T) {
|
||||
tests := []struct {
|
||||
name string
|
||||
deckSize int
|
||||
handSize int
|
||||
}{
|
||||
{
|
||||
"deckSize = handSize = 4",
|
||||
4,
|
||||
4,
|
||||
},
|
||||
{
|
||||
"deckSize = handSize = 8",
|
||||
8,
|
||||
8,
|
||||
},
|
||||
{
|
||||
"deckSize = handSize = 10",
|
||||
10,
|
||||
10,
|
||||
},
|
||||
{
|
||||
"deckSize = handSize = 12",
|
||||
12,
|
||||
12,
|
||||
},
|
||||
{
|
||||
"deckSize = 128, handSize = 8",
|
||||
128,
|
||||
8,
|
||||
},
|
||||
{
|
||||
"deckSize = 256, handSize = 7",
|
||||
256,
|
||||
7,
|
||||
},
|
||||
{
|
||||
"deckSize = 512, handSize = 6",
|
||||
512,
|
||||
6,
|
||||
},
|
||||
}
|
||||
for _, test := range tests {
|
||||
hashValue := rand.Uint64()
|
||||
t.Run(test.name, func(t *testing.T) {
|
||||
dealer, err := NewDealer(test.deckSize, test.handSize)
|
||||
if err != nil {
|
||||
t.Errorf("fail to create Dealer: %v", err)
|
||||
return
|
||||
}
|
||||
hand := make([]int, 0)
|
||||
hand = dealer.DealIntoHand(hashValue, hand)
|
||||
|
||||
// check cards number
|
||||
if len(hand) != int(test.handSize) {
|
||||
t.Errorf("test case %s fails in cards number", test.name)
|
||||
return
|
||||
}
|
||||
|
||||
// check cards range and duplication
|
||||
cardMap := make(map[int]struct{})
|
||||
for _, card := range hand {
|
||||
if card < 0 || card >= int(test.deckSize) {
|
||||
t.Errorf("test case %s fails in range check", test.name)
|
||||
return
|
||||
}
|
||||
cardMap[card] = struct{}{}
|
||||
}
|
||||
if len(cardMap) != int(test.handSize) {
|
||||
t.Errorf("test case %s fails in duplication check", test.name)
|
||||
return
|
||||
}
|
||||
|
||||
})
|
||||
}
|
||||
}
|
||||
|
||||
// ff computes the falling factorial `n!/(n-m)!` and requires n to be
|
||||
// positive and m to be in the range [0, n] and requires the answer to
|
||||
// fit in an int
|
||||
func ff(n, m int) int {
|
||||
ans := 1
|
||||
for f := n; f > n-m; f-- {
|
||||
ans *= f
|
||||
}
|
||||
return ans
|
||||
}
|
||||
|
||||
func TestUniformDistribution(t *testing.T) {
|
||||
const spare = 64 - MaxHashBits
|
||||
tests := []struct {
|
||||
deckSize, handSize int
|
||||
hashMax int
|
||||
}{
|
||||
{64, 3, 1 << uint(math.Ceil(math.Log2(float64(ff(64, 3))))+spare)},
|
||||
{128, 3, ff(128, 3)},
|
||||
{128, 3, 3 * ff(128, 3)},
|
||||
{70, 4, ff(70, 4)},
|
||||
}
|
||||
for _, test := range tests {
|
||||
dealer, err := NewDealer(test.deckSize, test.handSize)
|
||||
if err != nil {
|
||||
t.Errorf("fail to create Dealer: %v", err)
|
||||
return
|
||||
}
|
||||
handCoordinateMap := make(map[int]int) // maps coded hand to count of times seen
|
||||
|
||||
fallingFactorial := ff(test.deckSize, test.handSize)
|
||||
permutations := ff(test.handSize, test.handSize)
|
||||
allCoordinateCount := fallingFactorial / permutations
|
||||
nff := float64(test.hashMax) / float64(fallingFactorial)
|
||||
minCount := permutations * int(math.Floor(nff))
|
||||
maxCount := permutations * int(math.Ceil(nff))
|
||||
aHand := make([]int, test.handSize)
|
||||
for i := 0; i < test.hashMax; i++ {
|
||||
aHand = dealer.DealIntoHand(uint64(i), aHand)
|
||||
sort.IntSlice(aHand).Sort()
|
||||
handCoordinate := 0
|
||||
for _, card := range aHand {
|
||||
handCoordinate = handCoordinate<<7 + card
|
||||
}
|
||||
handCoordinateMap[handCoordinate]++
|
||||
}
|
||||
|
||||
t.Logf("Deck size = %v, hand size = %v, number of possible hands = %d, number of hands seen = %d, number of deals = %d, expected count range = [%v, %v]", test.deckSize, test.handSize, allCoordinateCount, len(handCoordinateMap), test.hashMax, minCount, maxCount)
|
||||
|
||||
// histogram maps (count of times a hand is seen) to (number of hands having that count)
|
||||
histogram := make(map[int]int)
|
||||
for _, count := range handCoordinateMap {
|
||||
histogram[count] = histogram[count] + 1
|
||||
}
|
||||
|
||||
var goodSum int
|
||||
for count := minCount; count <= maxCount; count++ {
|
||||
goodSum += histogram[count]
|
||||
}
|
||||
|
||||
goodPct := 100 * float64(goodSum) / float64(allCoordinateCount)
|
||||
|
||||
t.Logf("good percentage = %v, histogram = %v", goodPct, histogram)
|
||||
if goodSum != allCoordinateCount {
|
||||
t.Errorf("Only %v percent of the hands got a central count", goodPct)
|
||||
}
|
||||
}
|
||||
return
|
||||
}
|
||||
|
||||
func TestDealer_DealIntoHand(t *testing.T) {
|
||||
dealer, _ := NewDealer(6, 6)
|
||||
|
||||
tests := []struct {
|
||||
name string
|
||||
hand []int
|
||||
expectedSize int
|
||||
}{
|
||||
{
|
||||
"nil slice",
|
||||
nil,
|
||||
6,
|
||||
},
|
||||
{
|
||||
"empty slice",
|
||||
make([]int, 0),
|
||||
6,
|
||||
},
|
||||
{
|
||||
"size: 6 cap: 6 slice",
|
||||
make([]int, 6, 6),
|
||||
6,
|
||||
},
|
||||
{
|
||||
"size: 6 cap: 12 slice",
|
||||
make([]int, 6, 12),
|
||||
6,
|
||||
},
|
||||
{
|
||||
"size: 4 cap: 4 slice",
|
||||
make([]int, 4, 4),
|
||||
6,
|
||||
},
|
||||
{
|
||||
"size: 4 cap: 12 slice",
|
||||
make([]int, 4, 12),
|
||||
6,
|
||||
},
|
||||
{
|
||||
"size: 10 cap: 10 slice",
|
||||
make([]int, 10, 10),
|
||||
6,
|
||||
},
|
||||
{
|
||||
"size: 10 cap: 12 slice",
|
||||
make([]int, 10, 12),
|
||||
6,
|
||||
},
|
||||
}
|
||||
for _, test := range tests {
|
||||
t.Run(test.name, func(t *testing.T) {
|
||||
h := dealer.DealIntoHand(0, test.hand)
|
||||
if len(h) != test.expectedSize {
|
||||
t.Errorf("test %s fails: expetced size %d but got %d", test.name, test.expectedSize, len(h))
|
||||
return
|
||||
}
|
||||
})
|
||||
}
|
||||
}
|
||||
Loading…
Reference in New Issue
Block a user