144 lines
3.9 KiB
Go
144 lines
3.9 KiB
Go
package brutal
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import (
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"time"
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"github.com/apernet/quic-go/congestion"
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"github.com/apernet/quic-go/monotime"
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"github.com/niko/qcc/internal/congestion/common"
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)
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const (
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pktInfoSlotCount = 5
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minSampleCount = 50
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minAckRate = 0.8
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congestionWindowMultiplier = 2
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)
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var _ congestion.CongestionControl = &BrutalSender{}
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type BrutalSender struct {
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rttStats congestion.RTTStatsProvider
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bps congestion.ByteCount
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maxDatagramSize congestion.ByteCount
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pacer *common.Pacer
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pktInfoSlots [pktInfoSlotCount]pktInfo
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ackRate float64
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}
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type pktInfo struct {
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Timestamp int64
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AckCount uint64
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LossCount uint64
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}
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func NewBrutalSender(bps uint64) *BrutalSender {
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bs := &BrutalSender{
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bps: congestion.ByteCount(bps),
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maxDatagramSize: congestion.InitialPacketSize,
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ackRate: 1,
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}
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bs.pacer = common.NewPacer(func() congestion.ByteCount {
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return congestion.ByteCount(float64(bs.bps) / bs.ackRate)
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})
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return bs
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}
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func (b *BrutalSender) SetRTTStatsProvider(rttStats congestion.RTTStatsProvider) {
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b.rttStats = rttStats
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}
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func (b *BrutalSender) TimeUntilSend(bytesInFlight congestion.ByteCount) monotime.Time {
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return b.pacer.TimeUntilSend()
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}
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func (b *BrutalSender) HasPacingBudget(now monotime.Time) bool {
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return b.pacer.Budget(now) >= b.maxDatagramSize
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}
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func (b *BrutalSender) CanSend(bytesInFlight congestion.ByteCount) bool {
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return bytesInFlight <= b.GetCongestionWindow()
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}
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func (b *BrutalSender) GetCongestionWindow() congestion.ByteCount {
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rtt := b.rttStats.SmoothedRTT()
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if rtt <= 0 {
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return 10240
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}
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cwnd := congestion.ByteCount(float64(b.bps) * rtt.Seconds() * congestionWindowMultiplier / b.ackRate)
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if cwnd < b.maxDatagramSize {
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cwnd = b.maxDatagramSize
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}
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return cwnd
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}
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func (b *BrutalSender) OnPacketSent(sentTime monotime.Time, bytesInFlight congestion.ByteCount,
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packetNumber congestion.PacketNumber, bytes congestion.ByteCount, isRetransmittable bool,
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) {
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b.pacer.SentPacket(sentTime, bytes)
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}
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func (b *BrutalSender) OnPacketAcked(number congestion.PacketNumber, ackedBytes congestion.ByteCount,
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priorInFlight congestion.ByteCount, eventTime monotime.Time,
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) {
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}
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func (b *BrutalSender) OnCongestionEvent(number congestion.PacketNumber, lostBytes congestion.ByteCount,
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priorInFlight congestion.ByteCount,
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) {
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}
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func (b *BrutalSender) OnCongestionEventEx(priorInFlight congestion.ByteCount, eventTime monotime.Time, ackedPackets []congestion.AckedPacketInfo, lostPackets []congestion.LostPacketInfo) {
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currentTimestamp := int64(time.Duration(eventTime) / time.Second)
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slot := currentTimestamp % pktInfoSlotCount
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if b.pktInfoSlots[slot].Timestamp == currentTimestamp {
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b.pktInfoSlots[slot].LossCount += uint64(len(lostPackets))
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b.pktInfoSlots[slot].AckCount += uint64(len(ackedPackets))
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} else {
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b.pktInfoSlots[slot].Timestamp = currentTimestamp
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b.pktInfoSlots[slot].AckCount = uint64(len(ackedPackets))
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b.pktInfoSlots[slot].LossCount = uint64(len(lostPackets))
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}
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b.updateAckRate(currentTimestamp)
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}
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func (b *BrutalSender) SetMaxDatagramSize(size congestion.ByteCount) {
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b.maxDatagramSize = size
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b.pacer.SetMaxDatagramSize(size)
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}
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func (b *BrutalSender) updateAckRate(currentTimestamp int64) {
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minTimestamp := currentTimestamp - pktInfoSlotCount
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var ackCount, lossCount uint64
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for _, info := range b.pktInfoSlots {
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if info.Timestamp < minTimestamp {
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continue
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}
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ackCount += info.AckCount
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lossCount += info.LossCount
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}
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if ackCount+lossCount < minSampleCount {
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b.ackRate = 1
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return
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}
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rate := float64(ackCount) / float64(ackCount+lossCount)
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if rate < minAckRate {
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b.ackRate = minAckRate
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return
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}
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b.ackRate = rate
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}
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func (b *BrutalSender) InSlowStart() bool {
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return false
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}
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func (b *BrutalSender) InRecovery() bool {
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return false
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}
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func (b *BrutalSender) MaybeExitSlowStart() {}
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func (b *BrutalSender) OnRetransmissionTimeout(packetsRetransmitted bool) {}
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