From 9c51995cc43860128734621f576359931cfef0d3 Mon Sep 17 00:00:00 2001 From: Haruue Date: Sun, 10 Mar 2024 22:41:26 +0800 Subject: [PATCH] fix: cwnd undersize in extremely-low rtt scenarios Prevent the congestion window from falling below the size of single packet in scenarios with extremely low RTT, which previously led to transmission stalls. --- core/internal/congestion/brutal/brutal.go | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/core/internal/congestion/brutal/brutal.go b/core/internal/congestion/brutal/brutal.go index a9eabe8..4edd45d 100644 --- a/core/internal/congestion/brutal/brutal.go +++ b/core/internal/congestion/brutal/brutal.go @@ -69,7 +69,7 @@ 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 { @@ -77,7 +77,11 @@ func (b *BrutalSender) GetCongestionWindow() congestion.ByteCount { 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,