From f3f559705a05b65c99bdf02520475d595b111503 Mon Sep 17 00:00:00 2001 From: Richard Scheffenegger Date: Sat, 24 Feb 2024 17:07:25 +0100 Subject: [PATCH] tcp: cubic - restart epoch after RTO This is a migitation to avoid sudden extreme jumps in cwnd, as t_epoch can be very out of date after an RTO. Per RFC9438, sec 4.8, t_epoch is to be reset whenever cwnd grows beyond ssthresh (CC phase transitions from slow start to congestion avoidance), to be fixed with the upcoming cc_cubic changes. MFC after: 3 days Reviewed By: cc, #transport Sponsored by: NetApp, Inc Differential Revision: https://reviews.freebsd.org/D44023 (cherry picked from commit 038699a8f18a0a651ee06b85fa1dbbee1eab56f1) --- sys/netinet/cc/cc_cubic.c | 1 + 1 file changed, 1 insertion(+) diff --git a/sys/netinet/cc/cc_cubic.c b/sys/netinet/cc/cc_cubic.c index 031091c3b77..4579e7d3654 100644 --- a/sys/netinet/cc/cc_cubic.c +++ b/sys/netinet/cc/cc_cubic.c @@ -271,6 +271,7 @@ cubic_ack_received(struct cc_var *ccv, uint16_t type) cubic_data->flags &= ~(CUBICFLAG_RTO_EVENT | CUBICFLAG_IN_SLOWSTART); cubic_data->W_max = CCV(ccv, snd_cwnd); + cubic_data->t_epoch = ticks; cubic_data->K = 0; } else if (cubic_data->flags & (CUBICFLAG_IN_SLOWSTART | CUBICFLAG_IN_APPLIMIT)) {