| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.7 035/184] tcp: cwnd does not increase in TCP YeAH | Date | Thu, 22 Sep 2016 19:39:29 +0200 |
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4.7-stable review patch. If anyone has any objections, please let me know.
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From: Artem Germanov <agermanov@anchorfree.com>
[ 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@anchorfree.com> Acked-by: Dmitry Adamushko <d.adamushko@anchorfree.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- 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) {
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