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UDT: Remove ackInterval which was never set anyway. Instead, send ACK every few packets depending on congestion window and count of sent packets.

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Removing LightACK. The implementation of it was confusing (it competed with ACK in a race condition) and rather pointless. LightACKs will be ditched completely to get to a working version.
This commit is contained in:
Kleissner
2021-11-04 20:47:34 +01:00
parent d9bbdf573e
commit b728b939ec
3 changed files with 4 additions and 41 deletions
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3
udt/congestion.go
View File

@@ -38,9 +38,6 @@ type CongestionControlParms interface {
// SetACKPerid sets the time between ACKs sent to the peer
SetACKPeriod(time.Duration)
// SetACKInterval sets the number of packets sent to the peer before sending an ACK
SetACKInterval(uint)
// SetRTOPeriod overrides the default EXP timeout calculations waiting for data from the peer
SetRTOPeriod(time.Duration)
}

5
udt/udtsocket_cc.go
View File

@@ -216,11 +216,6 @@ func (s *udtSocketCc) SetACKPeriod(ack time.Duration) {
s.socket.recv.ackPeriod.set(ack)
}
// SetACKInterval sets the number of packets sent to the peer before sending an ACK
func (s *udtSocketCc) SetACKInterval(ack uint) {
s.socket.recv.ackInterval.set(uint32(ack))
}
// SetRTOPeriod overrides the default EXP timeout calculations waiting for data from the peer
func (s *udtSocketCc) SetRTOPeriod(rto time.Duration) {
s.socket.send.rtoPeriod.set(rto)

37
udt/udtsocket_recv.go
View File

@@ -8,10 +8,6 @@ import (
"github.com/PeernetOfficial/core/udt/packet"
)
const (
ackSelfClockInterval = 64
)
type udtSocketRecv struct {
// channels
sockClosed <-chan struct{} // closed when socket is closed
@@ -32,9 +28,7 @@ type udtSocketRecv struct {
recvLastArrival time.Time // time of the most recent data packet arrival
recvLastProbe time.Time // time of the most recent data packet probe packet
ackPeriod atomicDuration // (set by congestion control) delay between sending ACKs
ackInterval atomicUint32 // (set by congestion control) number of data packets to send before sending an ACK
unackPktCount uint // number of packets we've received that we haven't sent an ACK for
lightAckCount uint // number of "light ACK" packets we've sent since the last ACK
recvPktHistory []time.Duration // list of recently received packets.
recvPktPairHistory []time.Duration // probing packet window.
@@ -351,16 +345,12 @@ func (s *udtSocketRecv) attemptProcessPacket(p *packet.DataPacket, isNew bool) b
}
}
// we've received a data packet, do we need to send an ACK for it?
// Acknowledge the packet if the threshold is reached. This used to be a parameter s.ackInterval supposed to be set by congestion control, but never was.
// Before, there was both the (unused) ACK interval s.ackInterval and s.ackTimerEvent which fired at SynTime, which was way too often and basically a ddos.
// It makes more sense to just send the ACK x split of the congestion window.
s.unackPktCount++
ackInterval := uint(s.ackInterval.get())
if (ackInterval > 0) && (ackInterval <= s.unackPktCount) {
// ACK interval is reached
if s.unackPktCount >= s.socket.cong.GetCongestionWindowSize()/4 {
s.ackEvent()
} else if ackSelfClockInterval*s.lightAckCount <= s.unackPktCount {
//send a "light" ACK
s.sendLightACK()
s.lightAckCount++
}
if cannotContinue {
@@ -394,24 +384,6 @@ func (s *udtSocketRecv) attemptProcessPacket(p *packet.DataPacket, isNew bool) b
return true
}
func (s *udtSocketRecv) sendLightACK() {
var ack packet.PacketID
// If there is no loss, the ACK is the current largest sequence number plus 1;
// Otherwise it is the smallest sequence number in the receiver loss list.
if s.recvLossList == nil {
ack = s.farNextPktSeq
} else {
ack = s.farRecdPktSeq.Add(1)
}
if ack != s.recvAck2 {
// send out a lite ACK
// to save time on buffer processing and bandwidth/AS measurement, a lite ACK only feeds back an ACK number
s.sendPacket <- &packet.LightAckPacket{PktSeqHi: ack}
}
}
func (s *udtSocketRecv) getRcvSpeeds() (recvSpeed, bandwidth int) {
// get median value, but cannot change the original value order in the window
@@ -576,5 +548,4 @@ func (s *udtSocketRecv) ingestError(p *packet.ErrPacket) {
func (s *udtSocketRecv) ackEvent() {
s.sendACK()
s.unackPktCount = 0
s.lightAckCount = 1
}