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From: Eric Dumazet <edumazet@google.com>
To: "David S . Miller" <davem@davemloft.net>
Cc: netdev <netdev@vger.kernel.org>, Van Jacobson <vanj@google.com>,
	Neal Cardwell <ncardwell@google.com>,
	Yuchung Cheng <ycheng@google.com>,
	Soheil Hassas Yeganeh <soheil@google.com>,
	Willem de Bruijn <willemb@google.com>,
	Eric Dumazet <edumazet@google.com>,
	Eric Dumazet <eric.dumazet@gmail.com>
Subject: [PATCH net-next 8/9] tcp: switch tcp_internal_pacing() to tcp_wstamp_ns
Date: Fri, 21 Sep 2018 08:51:53 -0700	[thread overview]
Message-ID: <20180921155154.49489-9-edumazet@google.com> (raw)
In-Reply-To: <20180921155154.49489-1-edumazet@google.com>

Now TCP keeps track of tcp_wstamp_ns, recording the earliest
departure time of next packet, we can remove duplicate code
from tcp_internal_pacing()

This removes one ktime_get_tai_ns() call, and a divide.

Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 net/ipv4/tcp_output.c | 17 ++++-------------
 1 file changed, 4 insertions(+), 13 deletions(-)

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 2adb719e97b89021becfa1243d33c87df6cdf8a5..fe7855b090e4feed6a7d1ba6ee874cdb23a9bd0c 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -993,21 +993,12 @@ enum hrtimer_restart tcp_pace_kick(struct hrtimer *timer)
 	return HRTIMER_NORESTART;
 }
 
-static void tcp_internal_pacing(struct sock *sk, const struct sk_buff *skb)
+static void tcp_internal_pacing(struct sock *sk)
 {
-	u64 len_ns;
-	u32 rate;
-
 	if (!tcp_needs_internal_pacing(sk))
 		return;
-	rate = sk->sk_pacing_rate;
-	if (!rate || rate == ~0U)
-		return;
-
-	len_ns = (u64)skb->len * NSEC_PER_SEC;
-	do_div(len_ns, rate);
 	hrtimer_start(&tcp_sk(sk)->pacing_timer,
-		      ktime_add_ns(ktime_get_tai_ns(), len_ns),
+		      ns_to_ktime(tcp_sk(sk)->tcp_wstamp_ns),
 		      HRTIMER_MODE_ABS_PINNED_SOFT);
 	sock_hold(sk);
 }
@@ -1026,7 +1017,8 @@ static void tcp_update_skb_after_send(struct sock *sk, struct sk_buff *skb)
 		 */
 		if (rate != ~0U && rate && tp->data_segs_out >= 10) {
 			tp->tcp_wstamp_ns += div_u64((u64)skb->len * NSEC_PER_SEC, rate);
-			/* TODO: update internal pacing here */
+
+			tcp_internal_pacing(sk);
 		}
 	}
 	list_move_tail(&skb->tcp_tsorted_anchor, &tp->tsorted_sent_queue);
@@ -1167,7 +1159,6 @@ static int __tcp_transmit_skb(struct sock *sk, struct sk_buff *skb,
 		tcp_event_data_sent(tp, sk);
 		tp->data_segs_out += tcp_skb_pcount(skb);
 		tp->bytes_sent += skb->len - tcp_header_size;
-		tcp_internal_pacing(sk, skb);
 	}
 
 	if (after(tcb->end_seq, tp->snd_nxt) || tcb->seq == tcb->end_seq)
-- 
2.19.0.444.g18242da7ef-goog

  parent reply	other threads:[~2018-09-21 21:41 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-21 15:51 [PATCH net-next 0/9] tcp: switch to Early Departure Time model Eric Dumazet
2018-09-21 15:51 ` [PATCH net-next 1/9] tcp: switch tcp_clock_ns() to CLOCK_TAI base Eric Dumazet
2018-09-21 15:51 ` [PATCH net-next 2/9] tcp: introduce tcp_skb_timestamp_us() helper Eric Dumazet
2018-09-21 15:51 ` [PATCH net-next 3/9] net_sched: sch_fq: switch to CLOCK_TAI Eric Dumazet
2018-09-21 15:51 ` [PATCH net-next 4/9] tcp: add tcp_wstamp_ns socket field Eric Dumazet
2018-09-21 15:51 ` [PATCH net-next 5/9] tcp: provide earliest departure time in skb->tstamp Eric Dumazet
2018-09-21 15:51 ` [PATCH net-next 6/9] tcp: switch internal pacing timer to CLOCK_TAI Eric Dumazet
2018-09-21 15:51 ` [PATCH net-next 7/9] tcp: switch tcp and sch_fq to new earliest departure time model Eric Dumazet
2018-09-21 15:51 ` Eric Dumazet [this message]
2018-09-21 15:51 ` [PATCH net-next 9/9] net_sched: sch_fq: remove dead code dealing with retransmits Eric Dumazet

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