Re: [PATCH net-next 13/15] tcp_lp: cache tcp_time_stamp

[Soheil Hassas Yeganeh]

On Tue, May 16, 2017 at 5:00 PM, Eric Dumazet  wrote:
> tcp_time_stamp will become slightly more expensive soon,
> cache its value.
>
> Signed-off-by: Eric Dumazet 

Acked-by: Soheil Hassas Yeganeh 

> ---
>  net/ipv4/tcp_lp.c | 7 ---
>  1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/net/ipv4/tcp_lp.c b/net/ipv4/tcp_lp.c
> index 
> d6fb6c067af4641f232b94e7c590c212648e8173..ef3122abb3734a63011fba035f7a7aae431da8de
>  100644
> --- a/net/ipv4/tcp_lp.c
> +++ b/net/ipv4/tcp_lp.c
> @@ -264,18 +264,19 @@ static void tcp_lp_pkts_acked(struct sock *sk, const 
> struct ack_sample *sample)
>  {
> struct tcp_sock *tp = tcp_sk(sk);
> struct lp *lp = inet_csk_ca(sk);
> +   u32 now = tcp_time_stamp;
> u32 delta;
>
> if (sample->rtt_us > 0)
> tcp_lp_rtt_sample(sk, sample->rtt_us);
>
> /* calc inference */
> -   delta = tcp_time_stamp - tp->rx_opt.rcv_tsecr;
> +   delta = now - tp->rx_opt.rcv_tsecr;
> if ((s32)delta > 0)
> lp->inference = 3 * delta;
>
> /* test if within inference */
> -   if (lp->last_drop && (tcp_time_stamp - lp->last_drop < lp->inference))
> +   if (lp->last_drop && (now - lp->last_drop < lp->inference))
> lp->flag |= LP_WITHIN_INF;
> else
> lp->flag &= ~LP_WITHIN_INF;
> @@ -312,7 +313,7 @@ static void tcp_lp_pkts_acked(struct sock *sk, const 
> struct ack_sample *sample)
> tp->snd_cwnd = max(tp->snd_cwnd >> 1U, 1U);
>
> /* record this drop time */
> -   lp->last_drop = tcp_time_stamp;
> +   lp->last_drop = now;
>  }
>
>  static struct tcp_congestion_ops tcp_lp __read_mostly = {
> --
> 2.13.0.303.g4ebf302169-goog
>

[PATCH net-next 13/15] tcp_lp: cache tcp_time_stamp

[Eric Dumazet]

tcp_time_stamp will become slightly more expensive soon,
cache its value.

Signed-off-by: Eric Dumazet 
---
 net/ipv4/tcp_lp.c | 7 ---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/net/ipv4/tcp_lp.c b/net/ipv4/tcp_lp.c
index 
d6fb6c067af4641f232b94e7c590c212648e8173..ef3122abb3734a63011fba035f7a7aae431da8de
 100644
--- a/net/ipv4/tcp_lp.c
+++ b/net/ipv4/tcp_lp.c
@@ -264,18 +264,19 @@ static void tcp_lp_pkts_acked(struct sock *sk, const 
struct ack_sample *sample)
 {
struct tcp_sock *tp = tcp_sk(sk);
struct lp *lp = inet_csk_ca(sk);
+   u32 now = tcp_time_stamp;
u32 delta;
 
if (sample->rtt_us > 0)
tcp_lp_rtt_sample(sk, sample->rtt_us);
 
/* calc inference */
-   delta = tcp_time_stamp - tp->rx_opt.rcv_tsecr;
+   delta = now - tp->rx_opt.rcv_tsecr;
if ((s32)delta > 0)
lp->inference = 3 * delta;
 
/* test if within inference */
-   if (lp->last_drop && (tcp_time_stamp - lp->last_drop < lp->inference))
+   if (lp->last_drop && (now - lp->last_drop < lp->inference))
lp->flag |= LP_WITHIN_INF;
else
lp->flag &= ~LP_WITHIN_INF;
@@ -312,7 +313,7 @@ static void tcp_lp_pkts_acked(struct sock *sk, const struct 
ack_sample *sample)
tp->snd_cwnd = max(tp->snd_cwnd >> 1U, 1U);
 
/* record this drop time */
-   lp->last_drop = tcp_time_stamp;
+   lp->last_drop = now;
 }
 
 static struct tcp_congestion_ops tcp_lp __read_mostly = {
-- 
2.13.0.303.g4ebf302169-goog