Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit aab2b4bf authored by Neal Cardwell's avatar Neal Cardwell Committed by David S. Miller
Browse files

tcp: fix double-counted receiver RTT when leaving receiver fast path 



We should not update ts_recent and call tcp_rcv_rtt_measure_ts() both
before and after going to step5. That wastes CPU and double-counts the
receiver-side RTT sample.

Signed-off-by: default avatarNeal Cardwell <ncardwell@google.com>
Acked-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent d2123be0

net/ipv4/tcp_input.c

+3 −3
Original line number Diff line number Diff line
@@ -5485,6 +5485,9 @@ int tcp_rcv_established(struct sock *sk, struct sk_buff *skb, 
				if (tcp_checksum_complete_user(sk, skb))

					goto csum_error;



				if ((int)skb->truesize > sk->sk_forward_alloc)

					goto step5;



				/* Predicted packet is in window by definition.

				 * seq == rcv_nxt and rcv_wup <= rcv_nxt.

				 * Hence, check seq<=rcv_wup reduces to:
@@ -5496,9 +5499,6 @@ int tcp_rcv_established(struct sock *sk, struct sk_buff *skb, 


				tcp_rcv_rtt_measure_ts(sk, skb);



				if ((int)skb->truesize > sk->sk_forward_alloc)

					goto step5;



				NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPHPHITS);



				/* Bulk data transfer: receiver */