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Make all tests send number of reqs which is close to predefined const…
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…ant (#2867)

Signed-off-by: Roman Zavodskikh <[email protected]>
Co-authored-by: Roman Zavodskikh <[email protected]>
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@RomanZavodskikh
RomanZavodskikh and Roman Zavodskikh authored Jan 16, 2024
1 parent e8c099f commit e44f2b8
Showing 1 changed file with 58 additions and 27 deletions.
85 changes: 58 additions & 27 deletions loadbalancer/fadein_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -14,10 +14,12 @@ import (
)

const (
fadeInDuration = 500 * time.Millisecond
fadeInDurationHuge = 24 * time.Hour // we need this to be sure we're at the very beginning of fading in
fadeInRequestCount = 300_000
bucketCount = 20
monotonyTolerance = 0.4 // we need to use a high tolerance for CI testing

defaultFadeInDuration = 500 * time.Millisecond
defaultFadeInDurationHuge = 24 * time.Hour // we need this to be sure we're at the very beginning of fading in
)

func absint(i int) int {
Expand All @@ -44,16 +46,22 @@ func checkMonotony(direction, prev, next int) bool {
}
}

func initializeEndpoints(endpointAges []time.Duration, fadeInDuration time.Duration) (*routing.LBContext, []string) {
func multiply(k float64, d time.Duration) time.Duration {
return time.Duration(k * float64(d))
}

func initializeEndpoints(endpointAges []float64, fadeInDuration time.Duration) (*routing.LBContext, []string) {
var detectionTimes []time.Time
now := time.Now()
for _, ea := range endpointAges {
detectionTimes = append(detectionTimes, now.Add(-ea))
endpointAgeDuration := multiply(ea, fadeInDuration)
detectionTimes = append(detectionTimes, now.Add(-endpointAgeDuration))
}

var eps []string
for i := range endpointAges {
eps = append(eps, fmt.Sprintf("ep-%d-%s.test", i, endpointAges[i]))
for i, ea := range endpointAges {
endpointAgeDuration := multiply(ea, fadeInDuration)
eps = append(eps, fmt.Sprintf("ep-%d-%s.test", i, endpointAgeDuration))
}

ctx := &routing.LBContext{
Expand All @@ -77,17 +85,40 @@ func initializeEndpoints(endpointAges []time.Duration, fadeInDuration time.Durat
return ctx, eps
}

// This function is needed to calculate the duration needed to send fadeInRequestCount requests.
// It is needed to send number of requests close to fadeInRequestCount on one hand and to have them sent exactly
// in the fade-in duration returned on the other hand.
func calculateFadeInDuration(t *testing.T, algorithm func([]string) routing.LBAlgorithm, endpointAges []float64) time.Duration {
const precalculateRatio = 10

ctx, eps := initializeEndpoints(endpointAges, defaultFadeInDuration)
a := algorithm(eps)
rnd := rand.New(rand.NewSource(time.Now().UnixNano()))

t.Log("preemulation start", time.Now())
// Preemulate the load balancer loop to find out the approximate amount of RPS
begin := time.Now()
for i := 0; i < fadeInRequestCount/precalculateRatio; i++ {
ctx.Params[ConsistentHashKey] = strconv.Itoa(rnd.Intn(100000))
_ = a.Apply(ctx)
}
preemulationDuration := time.Since(begin)

return preemulationDuration * precalculateRatio
}

func testFadeIn(
t *testing.T,
name string,
algorithm func([]string) routing.LBAlgorithm,
endpointAges ...time.Duration,
endpointAges ...float64,
) {
t.Run(name, func(t *testing.T) {
fadeInDuration := calculateFadeInDuration(t, algorithm, endpointAges)
ctx, eps := initializeEndpoints(endpointAges, fadeInDuration)

a := algorithm(eps)
rnd := rand.New(rand.NewSource(time.Now().UnixNano()))

t.Log("test start", time.Now())
var stats []string
stop := time.After(fadeInDuration)
Expand Down Expand Up @@ -172,7 +203,7 @@ func newConsistentHashForTest(endpoints []string) routing.LBAlgorithm {
// Those tests check that the amount of requests per period for each endpoint is monotonical over the time.
// For every endpoint, it could increase, decrease or stay the same.
func TestFadeIn(t *testing.T) {
old := 2 * fadeInDuration
old := 2.0
testFadeIn(t, "power-of-n-random-choices, 0", newPowerOfRandomNChoices, old, old)
testFadeIn(t, "power-of-n-random-choices, 1", newPowerOfRandomNChoices, 0, old)
testFadeIn(t, "power-of-n-random-choices, 2", newPowerOfRandomNChoices, 0, 0)
Expand All @@ -182,7 +213,7 @@ func TestFadeIn(t *testing.T) {
testFadeIn(t, "power-of-n-random-choices, 6", newPowerOfRandomNChoices, old, 0, 0, 0)
testFadeIn(t, "power-of-n-random-choices, 7", newPowerOfRandomNChoices, old, 0, 0, 0, 0, 0, 0)
testFadeIn(t, "power-of-n-random-choices, 8", newPowerOfRandomNChoices, 0, 0, 0, 0, 0, 0)
testFadeIn(t, "power-of-n-random-choices, 9", newPowerOfRandomNChoices, fadeInDuration/2, fadeInDuration/3, fadeInDuration/4)
testFadeIn(t, "power-of-n-random-choices, 9", newPowerOfRandomNChoices, 1.0/2.0, 1.0/3.0, 1.0/4.0)

testFadeIn(t, "round-robin, 0", newRoundRobin, old, old)
testFadeIn(t, "round-robin, 1", newRoundRobin, 0, old)
Expand All @@ -193,7 +224,7 @@ func TestFadeIn(t *testing.T) {
testFadeIn(t, "round-robin, 6", newRoundRobin, old, 0, 0, 0)
testFadeIn(t, "round-robin, 7", newRoundRobin, old, 0, 0, 0, 0, 0, 0)
testFadeIn(t, "round-robin, 8", newRoundRobin, 0, 0, 0, 0, 0, 0)
testFadeIn(t, "round-robin, 9", newRoundRobin, fadeInDuration/2, fadeInDuration/3, fadeInDuration/4)
testFadeIn(t, "round-robin, 9", newRoundRobin, 1.0/2.0, 1.0/3.0, 1.0/4.0)

testFadeIn(t, "random, 0", newRandom, old, old)
testFadeIn(t, "random, 1", newRandom, 0, old)
Expand All @@ -204,7 +235,7 @@ func TestFadeIn(t *testing.T) {
testFadeIn(t, "random, 6", newRandom, old, 0, 0, 0)
testFadeIn(t, "random, 7", newRandom, old, 0, 0, 0, 0, 0, 0)
testFadeIn(t, "random, 8", newRandom, 0, 0, 0, 0, 0, 0)
testFadeIn(t, "random, 9", newRandom, fadeInDuration/2, fadeInDuration/3, fadeInDuration/4)
testFadeIn(t, "random, 9", newRandom, 1.0/2.0, 1.0/3.0, 1.0/4.0)

testFadeIn(t, "consistent-hash, 0", newConsistentHashForTest, old, old)
testFadeIn(t, "consistent-hash, 1", newConsistentHashForTest, 0, old)
Expand All @@ -215,7 +246,7 @@ func TestFadeIn(t *testing.T) {
testFadeIn(t, "consistent-hash, 6", newConsistentHashForTest, old, 0, 0, 0)
testFadeIn(t, "consistent-hash, 7", newConsistentHashForTest, old, 0, 0, 0, 0, 0, 0)
testFadeIn(t, "consistent-hash, 8", newConsistentHashForTest, 0, 0, 0, 0, 0, 0)
testFadeIn(t, "consistent-hash, 9", newConsistentHashForTest, fadeInDuration/2, fadeInDuration/3, fadeInDuration/4)
testFadeIn(t, "consistent-hash, 9", newConsistentHashForTest, 1.0/2.0, 1.0/3.0, 1.0/4.0)
}

func testFadeInLoadBetweenOldAndNewEps(
Expand All @@ -228,18 +259,18 @@ func testFadeInLoadBetweenOldAndNewEps(
const (
numberOfReqs = 100000
acceptableErrorNearZero = 10
old = fadeInDurationHuge
new = time.Duration(0)
old = 1.0
new = 0.0
)
endpointAges := []time.Duration{}
endpointAges := []float64{}
for i := 0; i < nOld; i++ {
endpointAges = append(endpointAges, old)
endpointAges = append(endpointAges, 1.0)
}
for i := 0; i < nNew; i++ {
endpointAges = append(endpointAges, new)
endpointAges = append(endpointAges, 0.0)
}

ctx, eps := initializeEndpoints(endpointAges, fadeInDurationHuge)
ctx, eps := initializeEndpoints(endpointAges, defaultFadeInDurationHuge)

a := algorithm(eps)
rnd := rand.New(rand.NewSource(time.Now().UnixNano()))
Expand Down Expand Up @@ -301,9 +332,9 @@ func testApplyEndsWhenAllEndpointsAreFading(
) {
t.Run(name, func(t *testing.T) {
// Initialize every endpoint with zero: every endpoint is new
endpointAges := make([]time.Duration, nEndpoints)
endpointAges := make([]float64, nEndpoints)

ctx, eps := initializeEndpoints(endpointAges, fadeInDurationHuge)
ctx, eps := initializeEndpoints(endpointAges, defaultFadeInDurationHuge)

a := algorithm(eps)
ctx.Params[ConsistentHashKey] = "someConstantString"
Expand Down Expand Up @@ -336,13 +367,13 @@ func benchmarkFadeIn(
name string,
algorithm func([]string) routing.LBAlgorithm,
clients int,
endpointAges ...time.Duration,
endpointAges ...float64,
) {
b.Run(name, func(b *testing.B) {
var detectionTimes []time.Time
now := time.Now()
for _, ea := range endpointAges {
detectionTimes = append(detectionTimes, now.Add(-ea))
detectionTimes = append(detectionTimes, now.Add(-defaultFadeInDuration*time.Duration(ea)))
}

var eps []string
Expand All @@ -353,7 +384,7 @@ func benchmarkFadeIn(
a := algorithm(eps)

route := &routing.Route{
LBFadeInDuration: fadeInDuration,
LBFadeInDuration: defaultFadeInDuration,
LBFadeInExponent: 1,
}
registry := routing.NewEndpointRegistry(routing.RegistryOptions{})
Expand Down Expand Up @@ -393,16 +424,16 @@ func benchmarkFadeIn(
})
}

func repeatedSlice(v time.Duration, n int) []time.Duration {
var s []time.Duration
func repeatedSlice(v float64, n int) []float64 {
var s []float64
for i := 0; i < n; i++ {
s = append(s, v)
}
return s
}

func BenchmarkFadeIn(b *testing.B) {
old := 2 * fadeInDuration
old := 2.0
clients := []int{1, 4, 16, 64, 256}
for _, c := range clients {
benchmarkFadeIn(b, fmt.Sprintf("random, 11, %d clients", c), newRandom, c, repeatedSlice(old, 200)...)
Expand Down

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