53 lines
1.5 KiB
Go
53 lines
1.5 KiB
Go
package main
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import (
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"sync"
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"github.com/lifenjoiner/ewma"
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)
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const (
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SizeEstimatorEwmaDecay = 100.0
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)
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type QuestionSizeEstimator struct {
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sync.RWMutex
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minQuestionSize int
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ewma *ewma.EWMA
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}
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func NewQuestionSizeEstimator() QuestionSizeEstimator {
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return QuestionSizeEstimator{
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minQuestionSize: InitialMinQuestionSize,
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ewma: ewma.NewMovingAverage(SizeEstimatorEwmaDecay),
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}
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}
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func (questionSizeEstimator *QuestionSizeEstimator) MinQuestionSize() int {
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questionSizeEstimator.RLock()
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minQuestionSize := questionSizeEstimator.minQuestionSize
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questionSizeEstimator.RUnlock()
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return minQuestionSize
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}
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func (questionSizeEstimator *QuestionSizeEstimator) blindAdjust() {
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questionSizeEstimator.Lock()
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if MaxDNSUDPPacketSize-questionSizeEstimator.minQuestionSize < questionSizeEstimator.minQuestionSize {
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questionSizeEstimator.minQuestionSize = MaxDNSUDPPacketSize
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} else {
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questionSizeEstimator.minQuestionSize *= 2
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}
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questionSizeEstimator.ewma.Set(float64(questionSizeEstimator.minQuestionSize))
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questionSizeEstimator.Unlock()
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}
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func (questionSizeEstimator *QuestionSizeEstimator) adjust(packetSize int) {
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questionSizeEstimator.Lock()
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questionSizeEstimator.ewma.Add(float64(packetSize))
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ma, minQuestionSize := int(questionSizeEstimator.ewma.Value()), questionSizeEstimator.minQuestionSize
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if ma > InitialMinQuestionSize && ma < minQuestionSize/2 {
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questionSizeEstimator.minQuestionSize = Max(InitialMinQuestionSize, minQuestionSize/2)
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}
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questionSizeEstimator.Unlock()
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}
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