tcp: cwnd does not increase in TCP YeAH

Commit 7617400 (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 <[email protected]> Acked-by: Dmitry Adamushko <[email protected]> Signed-off-by: David S. Miller <[email protected]>
josf · Sep 9, 2016 · db7196a · db7196a
1 parent 81d1a36
commit db7196a
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/net/ipv4/tcp_yeah.c b/net/ipv4/tcp_yeah.c
@@ -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) {