This is a note to let you know that I've just added the patch titled tcp: cwnd does not increase in TCP YeAH to the 4.7-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: tcp-cwnd-does-not-increase-in-tcp-yeah.patch and it can be found in the queue-4.7 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From foo@baz Wed Sep 21 10:05:18 CEST 2016 From: Artem Germanov <agermanov@xxxxxxxxxxxxxx> Date: Wed, 7 Sep 2016 10:49:36 -0700 Subject: tcp: cwnd does not increase in TCP YeAH From: Artem Germanov <agermanov@xxxxxxxxxxxxxx> [ Upstream commit db7196a0d0984b933ccf2cd6a60e26abf466e8a3 ] Commit 76174004a0f19785a328f40388e87e982bbf69b9 (tcp: do not slow start when cwnd equals ssthresh ) introduced regression in TCP YeAH. Using 100ms delay 1% loss virtual ethernet link kernel 4.2 shows bandwidth ~500KB/s for single TCP connection and kernel 4.3 and above (including 4.8-rc4) shows bandwidth ~100KB/s. That is caused by stalled cwnd when cwnd equals ssthresh. This patch fixes it by proper increasing cwnd in this case. Signed-off-by: Artem Germanov <agermanov@xxxxxxxxxxxxxx> Acked-by: Dmitry Adamushko <d.adamushko@xxxxxxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/ipv4/tcp_yeah.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/net/ipv4/tcp_yeah.c +++ b/net/ipv4/tcp_yeah.c @@ -76,7 +76,7 @@ static void tcp_yeah_cong_avoid(struct s if (!tcp_is_cwnd_limited(sk)) return; - if (tp->snd_cwnd <= tp->snd_ssthresh) + if (tcp_in_slow_start(tp)) tcp_slow_start(tp, acked); else if (!yeah->doing_reno_now) { Patches currently in stable-queue which might be from agermanov@xxxxxxxxxxxxxx are queue-4.7/tcp-cwnd-does-not-increase-in-tcp-yeah.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html