kpatch/examples/tcp_cubic-better-follow-cub...

59 lines
1.7 KiB
Diff

This patch is for 3.10.x.
It combines the following commits from the mainline:
commit 30927520dbae297182990bb21d08762bcc35ce1d
Author: Eric Dumazet <edumazet@google.com>
Date: Wed Sep 9 21:55:07 2015 -0700
tcp_cubic: better follow cubic curve after idle period
commit c2e7204d180f8efc80f27959ca9cf16fa17f67db
Author: Eric Dumazet <edumazet@google.com>
Date: Thu Sep 17 08:38:00 2015 -0700
tcp_cubic: do not set epoch_start in the future
References:
http://www.phoronix.com/scan.php?page=news_item&px=Google-Fixes-TCP-Linux
diff --git a/net/ipv4/tcp_cubic.c b/net/ipv4/tcp_cubic.c
index 894b7ce..872b3a0 100644
--- a/net/ipv4/tcp_cubic.c
+++ b/net/ipv4/tcp_cubic.c
@@ -153,6 +153,27 @@ static void bictcp_init(struct sock *sk)
tcp_sk(sk)->snd_ssthresh = initial_ssthresh;
}
+static void bictcp_cwnd_event(struct sock *sk, enum tcp_ca_event event)
+{
+ if (event == CA_EVENT_TX_START) {
+ struct bictcp *ca = inet_csk_ca(sk);
+ u32 now = tcp_time_stamp;
+ s32 delta;
+
+ delta = now - tcp_sk(sk)->lsndtime;
+
+ /* We were application limited (idle) for a while.
+ * Shift epoch_start to keep cwnd growth to cubic curve.
+ */
+ if (ca->epoch_start && delta > 0) {
+ ca->epoch_start += delta;
+ if (after(ca->epoch_start, now))
+ ca->epoch_start = now;
+ }
+ return;
+ }
+}
+
/* calculate the cubic root of x using a table lookup followed by one
* Newton-Raphson iteration.
* Avg err ~= 0.195%
@@ -439,6 +460,7 @@ static struct tcp_congestion_ops cubictcp __read_mostly = {
.cong_avoid = bictcp_cong_avoid,
.set_state = bictcp_state,
.undo_cwnd = bictcp_undo_cwnd,
+ .cwnd_event = bictcp_cwnd_event,
.pkts_acked = bictcp_acked,
.owner = THIS_MODULE,
.name = "cubic",