From b2ea46fe236ae02d845f94cf984cbc1786870333 Mon Sep 17 00:00:00 2001 From: Pavel Kubelun Date: Tue, 25 Jul 2017 03:57:31 -0400 Subject: generic: net: tcp: backport tcp tx performance patches 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 --- ...-tcp-tsq-add-shortcut-in-tcp_tasklet_func.patch | 71 ++++++++++++++++++++++ 1 file changed, 71 insertions(+) create mode 100644 target/linux/generic/backport-4.9/024-3-tcp-tsq-add-shortcut-in-tcp_tasklet_func.patch (limited to 'target/linux/generic/backport-4.9/024-3-tcp-tsq-add-shortcut-in-tcp_tasklet_func.patch') diff --git a/target/linux/generic/backport-4.9/024-3-tcp-tsq-add-shortcut-in-tcp_tasklet_func.patch b/target/linux/generic/backport-4.9/024-3-tcp-tsq-add-shortcut-in-tcp_tasklet_func.patch new file mode 100644 index 0000000000..8f45c23e3f --- /dev/null +++ b/target/linux/generic/backport-4.9/024-3-tcp-tsq-add-shortcut-in-tcp_tasklet_func.patch @@ -0,0 +1,71 @@ +From b223feb9de2a65c533ff95c08e834fa732906ea5 Mon Sep 17 00:00:00 2001 +From: Eric Dumazet +Date: Sat, 3 Dec 2016 11:14:52 -0800 +Subject: [PATCH 03/10] tcp: tsq: add shortcut in tcp_tasklet_func() + +Under high stress, I've seen tcp_tasklet_func() consuming +~700 usec, handling ~150 tcp sockets. + +By setting TCP_TSQ_DEFERRED in tcp_wfree(), we give a chance +for other cpus/threads entering tcp_write_xmit() to grab it, +allowing tcp_tasklet_func() to skip sockets that already did +an xmit cycle. + +In the future, we might give to ACK processing an increased +budget to reduce even more tcp_tasklet_func() amount of work. + +Signed-off-by: Eric Dumazet +Signed-off-by: David S. Miller +--- + net/ipv4/tcp_output.c | 22 ++++++++++++---------- + 1 file changed, 12 insertions(+), 10 deletions(-) + +--- a/net/ipv4/tcp_output.c ++++ b/net/ipv4/tcp_output.c +@@ -767,19 +767,19 @@ static void tcp_tasklet_func(unsigned lo + list_for_each_safe(q, n, &list) { + tp = list_entry(q, struct tcp_sock, tsq_node); + list_del(&tp->tsq_node); ++ clear_bit(TSQ_QUEUED, &tp->tsq_flags); + + sk = (struct sock *)tp; +- bh_lock_sock(sk); +- +- if (!sock_owned_by_user(sk)) { +- tcp_tsq_handler(sk); +- } else { +- /* defer the work to tcp_release_cb() */ +- set_bit(TCP_TSQ_DEFERRED, &tp->tsq_flags); ++ if (!sk->sk_lock.owned && ++ test_bit(TCP_TSQ_DEFERRED, &tp->tsq_flags)) { ++ bh_lock_sock(sk); ++ if (!sock_owned_by_user(sk)) { ++ clear_bit(TCP_TSQ_DEFERRED, &tp->tsq_flags); ++ tcp_tsq_handler(sk); ++ } ++ bh_unlock_sock(sk); + } +- bh_unlock_sock(sk); + +- clear_bit(TSQ_QUEUED, &tp->tsq_flags); + sk_free(sk); + } + } +@@ -884,7 +884,7 @@ void tcp_wfree(struct sk_buff *skb) + if (!(oval & TSQF_THROTTLED) || (oval & TSQF_QUEUED)) + goto out; + +- nval = (oval & ~TSQF_THROTTLED) | TSQF_QUEUED; ++ nval = (oval & ~TSQF_THROTTLED) | TSQF_QUEUED | TCPF_TSQ_DEFERRED; + nval = cmpxchg(&tp->tsq_flags, oval, nval); + if (nval != oval) + continue; +@@ -2179,6 +2179,8 @@ static bool tcp_write_xmit(struct sock * + unlikely(tso_fragment(sk, skb, limit, mss_now, gfp))) + break; + ++ if (test_bit(TCP_TSQ_DEFERRED, &tp->tsq_flags)) ++ clear_bit(TCP_TSQ_DEFERRED, &tp->tsq_flags); + if (tcp_small_queue_check(sk, skb, 0)) + break; + -- cgit v1.2.3