b2ea46fe23
An overall throughput gain of 22 % for heavy TCP use over a single TX queue. Original patchset comment https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?h=v4.13&id=3f4888adae7c1619b990d98a9b967536f71822b8 Signed-off-by: Pavel Kubelun <be.dissent@gmail.com>
55 lines
1.8 KiB
Diff
55 lines
1.8 KiB
Diff
From 12a59abc22d6664f7d3944f625ceefee92de8820 Mon Sep 17 00:00:00 2001
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From: Eric Dumazet <edumazet@google.com>
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Date: Sat, 3 Dec 2016 11:14:55 -0800
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Subject: [PATCH 06/10] tcp: tcp_mtu_probe() is likely to exit early
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Adding a likely() in tcp_mtu_probe() moves its code which used to
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be inlined in front of tcp_write_xmit()
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We still have a cache line miss to access icsk->icsk_mtup.enabled,
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we will probably have to reorganize fields to help data locality.
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Signed-off-by: Eric Dumazet <edumazet@google.com>
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Signed-off-by: David S. Miller <davem@davemloft.net>
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---
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net/ipv4/tcp_output.c | 18 +++++++++---------
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1 file changed, 9 insertions(+), 9 deletions(-)
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--- a/net/ipv4/tcp_output.c
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+++ b/net/ipv4/tcp_output.c
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@@ -1925,26 +1925,26 @@ static inline void tcp_mtu_check_reprobe
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*/
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static int tcp_mtu_probe(struct sock *sk)
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{
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- struct tcp_sock *tp = tcp_sk(sk);
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struct inet_connection_sock *icsk = inet_csk(sk);
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+ struct tcp_sock *tp = tcp_sk(sk);
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struct sk_buff *skb, *nskb, *next;
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struct net *net = sock_net(sk);
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- int len;
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int probe_size;
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int size_needed;
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- int copy;
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+ int copy, len;
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int mss_now;
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int interval;
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/* Not currently probing/verifying,
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* not in recovery,
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* have enough cwnd, and
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- * not SACKing (the variable headers throw things off) */
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- if (!icsk->icsk_mtup.enabled ||
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- icsk->icsk_mtup.probe_size ||
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- inet_csk(sk)->icsk_ca_state != TCP_CA_Open ||
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- tp->snd_cwnd < 11 ||
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- tp->rx_opt.num_sacks || tp->rx_opt.dsack)
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+ * not SACKing (the variable headers throw things off)
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+ */
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+ if (likely(!icsk->icsk_mtup.enabled ||
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+ icsk->icsk_mtup.probe_size ||
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+ inet_csk(sk)->icsk_ca_state != TCP_CA_Open ||
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+ tp->snd_cwnd < 11 ||
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+ tp->rx_opt.num_sacks || tp->rx_opt.dsack))
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return -1;
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/* Use binary search for probe_size between tcp_mss_base,
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