Re: [PATCH net-next 04/15] tcp: use tcp_jiffies32 to feed tp->lsndtime

[Soheil Hassas Yeganeh]

On Tue, May 16, 2017 at 5:00 PM, Eric Dumazet  wrote:
> Use tcp_jiffies32 instead of tcp_time_stamp to feed
> tp->lsndtime.
>
> tcp_time_stamp will soon be a litle bit more expensive
> than simply reading 'jiffies'.
>
> Signed-off-by: Eric Dumazet 

Acked-by: Soheil Hassas Yeganeh 

> ---
>  include/net/tcp.h | 2 +-
>  net/ipv4/tcp.c| 2 +-
>  net/ipv4/tcp_cubic.c  | 2 +-
>  net/ipv4/tcp_input.c  | 4 ++--
>  net/ipv4/tcp_output.c | 4 ++--
>  net/ipv4/tcp_timer.c  | 4 ++--
>  6 files changed, 9 insertions(+), 9 deletions(-)
>
> diff --git a/include/net/tcp.h b/include/net/tcp.h
> index 
> 4b45be5708215bae4551a5430b63ab2777baf447..feba4c0406e551d7e57da3411476735731b4d817
>  100644
> --- a/include/net/tcp.h
> +++ b/include/net/tcp.h
> @@ -1245,7 +1245,7 @@ static inline void 
> tcp_slow_start_after_idle_check(struct sock *sk)
> if (!sysctl_tcp_slow_start_after_idle || tp->packets_out ||
> ca_ops->cong_control)
> return;
> -   delta = tcp_time_stamp - tp->lsndtime;
> +   delta = tcp_jiffies32 - tp->lsndtime;
> if (delta > inet_csk(sk)->icsk_rto)
> tcp_cwnd_restart(sk, delta);
>  }
> diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
> index 
> 1e4c76d2b8278ba71d6cc2cf7ebfe483e241f76e..d0bb61ee28bbceff8f2e27416ce87fec94935973
>  100644
> --- a/net/ipv4/tcp.c
> +++ b/net/ipv4/tcp.c
> @@ -2841,7 +2841,7 @@ void tcp_get_info(struct sock *sk, struct tcp_info 
> *info)
> info->tcpi_retrans = tp->retrans_out;
> info->tcpi_fackets = tp->fackets_out;
>
> -   now = tcp_time_stamp;
> +   now = tcp_jiffies32;
> info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime);
> info->tcpi_last_data_recv = jiffies_to_msecs(now - 
> icsk->icsk_ack.lrcvtime);
> info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);
> diff --git a/net/ipv4/tcp_cubic.c b/net/ipv4/tcp_cubic.c
> index 
> 0683ba447d775b6101a929a6aca3eb255cff8932..2052ca740916d0872a41125ab61b769b334a314b
>  100644
> --- a/net/ipv4/tcp_cubic.c
> +++ b/net/ipv4/tcp_cubic.c
> @@ -155,7 +155,7 @@ 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;
> +   u32 now = tcp_jiffies32;
> s32 delta;
>
> delta = now - tcp_sk(sk)->lsndtime;
> diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
> index 
> 06e2dbc2b4a212a054fd88e57bb902c55a171b11..c0b3f909df394214785749704f2760171fe9d160
>  100644
> --- a/net/ipv4/tcp_input.c
> +++ b/net/ipv4/tcp_input.c
> @@ -5571,7 +5571,7 @@ void tcp_finish_connect(struct sock *sk, struct sk_buff 
> *skb)
> /* Prevent spurious tcp_cwnd_restart() on first data
>  * packet.
>  */
> -   tp->lsndtime = tcp_time_stamp;
> +   tp->lsndtime = tcp_jiffies32;
>
> tcp_init_buffer_space(sk);
>
> @@ -6008,7 +6008,7 @@ int tcp_rcv_state_process(struct sock *sk, struct 
> sk_buff *skb)
> tcp_update_pacing_rate(sk);
>
> /* Prevent spurious tcp_cwnd_restart() on first data packet */
> -   tp->lsndtime = tcp_time_stamp;
> +   tp->lsndtime = tcp_jiffies32;
>
> tcp_initialize_rcv_mss(sk);
> tcp_fast_path_on(tp);
> diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
> index 
> 4c8a6eaba6b39a2aea061dd6857ed8df954c5ca2..be9f8f483e21bdbb4d944fcdae8560f3ae11ee64
>  100644
> --- a/net/ipv4/tcp_output.c
> +++ b/net/ipv4/tcp_output.c
> @@ -160,7 +160,7 @@ static void tcp_event_data_sent(struct tcp_sock *tp,
> struct sock *sk)
>  {
> struct inet_connection_sock *icsk = inet_csk(sk);
> -   const u32 now = tcp_time_stamp;
> +   const u32 now = tcp_jiffies32;
>
> if (tcp_packets_in_flight(tp) == 0)
> tcp_ca_event(sk, CA_EVENT_TX_START);
> @@ -1918,7 +1918,7 @@ static bool tcp_tso_should_defer(struct sock *sk, 
> struct sk_buff *skb,
> /* Avoid bursty behavior by allowing defer
>  * only if the last write was recent.
>  */
> -   if ((s32)(tcp_time_stamp - tp->lsndtime) > 0)
> +   if ((s32)(tcp_jiffies32 - tp->lsndtime) > 0)
> goto send_now;
>
> in_flight = tcp_packets_in_flight(tp);
> diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c
> index 
> ec7c5473c788d77ae459b38492f2f2606d00d1ba..5f6f219a431e41a90b3c5d667a1a22b50f4464cf
>  100644
> --- a/net/ipv4/tcp_timer.c
> +++ b/net/ipv4/tcp_timer.c
> @@ -63,7 +63,7 @@ static int tcp_out_of_resources(struct sock *sk, bool 
> do_reset)
>
> /* If peer does not open window for long time, or did not transmit
>  * anything for long time, penalize it. */
> -   if ((s32)(tcp_time_stamp - tp->lsndtime) > 2*TCP_RTO_MAX || !do_reset)
> +   

[PATCH net-next 04/15] tcp: use tcp_jiffies32 to feed tp->lsndtime

[Eric Dumazet]

Use tcp_jiffies32 instead of tcp_time_stamp to feed
tp->lsndtime.

tcp_time_stamp will soon be a litle bit more expensive
than simply reading 'jiffies'.

Signed-off-by: Eric Dumazet 
---
 include/net/tcp.h | 2 +-
 net/ipv4/tcp.c| 2 +-
 net/ipv4/tcp_cubic.c  | 2 +-
 net/ipv4/tcp_input.c  | 4 ++--
 net/ipv4/tcp_output.c | 4 ++--
 net/ipv4/tcp_timer.c  | 4 ++--
 6 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/include/net/tcp.h b/include/net/tcp.h
index 
4b45be5708215bae4551a5430b63ab2777baf447..feba4c0406e551d7e57da3411476735731b4d817
 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -1245,7 +1245,7 @@ static inline void tcp_slow_start_after_idle_check(struct 
sock *sk)
if (!sysctl_tcp_slow_start_after_idle || tp->packets_out ||
ca_ops->cong_control)
return;
-   delta = tcp_time_stamp - tp->lsndtime;
+   delta = tcp_jiffies32 - tp->lsndtime;
if (delta > inet_csk(sk)->icsk_rto)
tcp_cwnd_restart(sk, delta);
 }
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 
1e4c76d2b8278ba71d6cc2cf7ebfe483e241f76e..d0bb61ee28bbceff8f2e27416ce87fec94935973
 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2841,7 +2841,7 @@ void tcp_get_info(struct sock *sk, struct tcp_info *info)
info->tcpi_retrans = tp->retrans_out;
info->tcpi_fackets = tp->fackets_out;
 
-   now = tcp_time_stamp;
+   now = tcp_jiffies32;
info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime);
info->tcpi_last_data_recv = jiffies_to_msecs(now - 
icsk->icsk_ack.lrcvtime);
info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);
diff --git a/net/ipv4/tcp_cubic.c b/net/ipv4/tcp_cubic.c
index 
0683ba447d775b6101a929a6aca3eb255cff8932..2052ca740916d0872a41125ab61b769b334a314b
 100644
--- a/net/ipv4/tcp_cubic.c
+++ b/net/ipv4/tcp_cubic.c
@@ -155,7 +155,7 @@ 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;
+   u32 now = tcp_jiffies32;
s32 delta;
 
delta = now - tcp_sk(sk)->lsndtime;
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 
06e2dbc2b4a212a054fd88e57bb902c55a171b11..c0b3f909df394214785749704f2760171fe9d160
 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -5571,7 +5571,7 @@ void tcp_finish_connect(struct sock *sk, struct sk_buff 
*skb)
/* Prevent spurious tcp_cwnd_restart() on first data
 * packet.
 */
-   tp->lsndtime = tcp_time_stamp;
+   tp->lsndtime = tcp_jiffies32;
 
tcp_init_buffer_space(sk);
 
@@ -6008,7 +6008,7 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff 
*skb)
tcp_update_pacing_rate(sk);
 
/* Prevent spurious tcp_cwnd_restart() on first data packet */
-   tp->lsndtime = tcp_time_stamp;
+   tp->lsndtime = tcp_jiffies32;
 
tcp_initialize_rcv_mss(sk);
tcp_fast_path_on(tp);
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 
4c8a6eaba6b39a2aea061dd6857ed8df954c5ca2..be9f8f483e21bdbb4d944fcdae8560f3ae11ee64
 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -160,7 +160,7 @@ static void tcp_event_data_sent(struct tcp_sock *tp,
struct sock *sk)
 {
struct inet_connection_sock *icsk = inet_csk(sk);
-   const u32 now = tcp_time_stamp;
+   const u32 now = tcp_jiffies32;
 
if (tcp_packets_in_flight(tp) == 0)
tcp_ca_event(sk, CA_EVENT_TX_START);
@@ -1918,7 +1918,7 @@ static bool tcp_tso_should_defer(struct sock *sk, struct 
sk_buff *skb,
/* Avoid bursty behavior by allowing defer
 * only if the last write was recent.
 */
-   if ((s32)(tcp_time_stamp - tp->lsndtime) > 0)
+   if ((s32)(tcp_jiffies32 - tp->lsndtime) > 0)
goto send_now;
 
in_flight = tcp_packets_in_flight(tp);
diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c
index 
ec7c5473c788d77ae459b38492f2f2606d00d1ba..5f6f219a431e41a90b3c5d667a1a22b50f4464cf
 100644
--- a/net/ipv4/tcp_timer.c
+++ b/net/ipv4/tcp_timer.c
@@ -63,7 +63,7 @@ static int tcp_out_of_resources(struct sock *sk, bool 
do_reset)
 
/* If peer does not open window for long time, or did not transmit
 * anything for long time, penalize it. */
-   if ((s32)(tcp_time_stamp - tp->lsndtime) > 2*TCP_RTO_MAX || !do_reset)
+   if ((s32)(tcp_jiffies32 - tp->lsndtime) > 2*TCP_RTO_MAX || !do_reset)
shift++;
 
/* If some dubious ICMP arrived, penalize even more. */
@@ -73,7 +73,7 @@ static int tcp_out_of_resources(struct sock *sk, bool 
do_reset)
if (tcp_check_oom(sk, shift)) {
/* Catch exceptional cases, when connection requires reset.