Commit db7196a0 authored Sep 07, 2016 by Artem Germanov Committed by David S. Miller Sep 08, 2016

tcp: cwnd does not increase in TCP YeAH



Commit 76174004
(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>

parent 81d1a366

net/ipv4/tcp_yeah.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -76,7 +76,7 @@ static void tcp_yeah_cong_avoid(struct sock *sk, u32 ack, u32 acked)
		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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