Merge pull request #973 from apernet/fix-cwnd-undersize

fix: cwnd undersize in extremely-low rtt scenarios
apernet · Mar 11, 2024 · 16ec455 · 16ec455
2 parents 02baab1 + 9c51995
commit 16ec455
Showing 1 changed file with 6 additions and 2 deletions.
diff --git a/core/internal/congestion/brutal/brutal.go b/core/internal/congestion/brutal/brutal.go
@@ -69,15 +69,19 @@ func (b *BrutalSender) HasPacingBudget(now time.Time) bool {
 }
 
 func (b *BrutalSender) CanSend(bytesInFlight congestion.ByteCount) bool {
-	return bytesInFlight < b.GetCongestionWindow()
+	return bytesInFlight <= b.GetCongestionWindow()
 }
 
 func (b *BrutalSender) GetCongestionWindow() congestion.ByteCount {
 	rtt := b.rttStats.SmoothedRTT()
 	if rtt <= 0 {
 		return 10240
 	}
-	return congestion.ByteCount(float64(b.bps) * rtt.Seconds() * congestionWindowMultiplier / b.ackRate)
+	cwnd := congestion.ByteCount(float64(b.bps) * rtt.Seconds() * congestionWindowMultiplier / b.ackRate)
+	if cwnd < b.maxDatagramSize {
+		cwnd = b.maxDatagramSize
+	}
+	return cwnd
 }
 
 func (b *BrutalSender) OnPacketSent(sentTime time.Time, bytesInFlight congestion.ByteCount,