From 569e289555c48b2adff6606ea66d650b6620de66 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Viktor=20Tigerstr=C3=B6m?= Date: Tue, 7 Nov 2023 14:50:11 +0100 Subject: [PATCH] gbn: increase NACK wait time by 2X --- gbn/gbn_conn.go | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/gbn/gbn_conn.go b/gbn/gbn_conn.go index 08a6db12..6350b65a 100644 --- a/gbn/gbn_conn.go +++ b/gbn/gbn_conn.go @@ -579,8 +579,18 @@ func (g *GoBackNConn) receivePacketsForever() error { // nolint:gocyclo // If we recently sent a NACK for the same // sequence number then back off. - if lastNackSeq == g.recvSeq && - time.Since(lastNackTime) < g.resendTimeout { + // We wait 2 times the resendTimeout before + // sending a new nack, as this case is likely + // hit if the sender is currently resending + // the queue, and therefore the threads that + // are resending the queue is likely busy with + // the resend, and therefore won't react to the + // NACK we send here in time. + sinceSent := time.Since(lastNackTime) + recentlySent := sinceSent < g.resendTimeout*2 //nolint:gomnd + + if lastNackSeq == g.recvSeq && recentlySent { + log.Tracef("Recently sent NACK") continue }