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authorEric Dumazet <edumazet@google.com>2019-12-23 12:27:50 -0800
committerDavid S. Miller <davem@davemloft.net>2019-12-27 16:29:14 -0800
commit473900a504e510cf9175876de8892ad1e3e7efab (patch)
tree7e7d854cf26dddd7dc142e08d90f08b27f9d88d9 /net/ipv4/tcp_cubic.c
parent2bbc078f812d45b8decb55935dab21199bd21489 (diff)
downloadlinux-473900a504e510cf9175876de8892ad1e3e7efab.tar.bz2
tcp_cubic: optimize hystart_update()
We do not care which bit in ca->found is set. We avoid accessing hystart and hystart_detect unless really needed, possibly avoiding one cache line miss. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp_cubic.c')
-rw-r--r--net/ipv4/tcp_cubic.c9
1 files changed, 3 insertions, 6 deletions
diff --git a/net/ipv4/tcp_cubic.c b/net/ipv4/tcp_cubic.c
index 1b3d032a4df2..297936033c33 100644
--- a/net/ipv4/tcp_cubic.c
+++ b/net/ipv4/tcp_cubic.c
@@ -381,9 +381,6 @@ static void hystart_update(struct sock *sk, u32 delay)
struct tcp_sock *tp = tcp_sk(sk);
struct bictcp *ca = inet_csk_ca(sk);
- if (ca->found & hystart_detect)
- return;
-
if (hystart_detect & HYSTART_ACK_TRAIN) {
u32 now = bictcp_clock();
@@ -391,7 +388,7 @@ static void hystart_update(struct sock *sk, u32 delay)
if ((s32)(now - ca->last_ack) <= hystart_ack_delta) {
ca->last_ack = now;
if ((s32)(now - ca->round_start) > ca->delay_min >> 4) {
- ca->found |= HYSTART_ACK_TRAIN;
+ ca->found = 1;
NET_INC_STATS(sock_net(sk),
LINUX_MIB_TCPHYSTARTTRAINDETECT);
NET_ADD_STATS(sock_net(sk),
@@ -412,7 +409,7 @@ static void hystart_update(struct sock *sk, u32 delay)
} else {
if (ca->curr_rtt > ca->delay_min +
HYSTART_DELAY_THRESH(ca->delay_min >> 3)) {
- ca->found |= HYSTART_DELAY;
+ ca->found = 1;
NET_INC_STATS(sock_net(sk),
LINUX_MIB_TCPHYSTARTDELAYDETECT);
NET_ADD_STATS(sock_net(sk),
@@ -450,7 +447,7 @@ static void bictcp_acked(struct sock *sk, const struct ack_sample *sample)
ca->delay_min = delay;
/* hystart triggers when cwnd is larger than some threshold */
- if (hystart && tcp_in_slow_start(tp) &&
+ if (!ca->found && hystart && tcp_in_slow_start(tp) &&
tp->snd_cwnd >= hystart_low_window)
hystart_update(sk, delay);
}