53 lines
1.9 KiB
Diff
53 lines
1.9 KiB
Diff
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From ce1cd7869a208112a8728d1fe9e373f78a2e4a6e Mon Sep 17 00:00:00 2001
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From: Neal Cardwell <ncardwell@google.com>
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Date: Tue, 11 Jun 2019 12:26:55 -0400
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Subject: [PATCH 01/19] net-tcp_bbr: broaden app-limited rate sample detection
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This commit is a bug fix for the Linux TCP app-limited
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(application-limited) logic that is used for collecting rate
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(bandwidth) samples.
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Previously the app-limited logic only looked for "bubbles" of
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silence in between application writes, by checking at the start
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of each sendmsg. But "bubbles" of silence can also happen before
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retransmits: e.g. bubbles can happen between an application write
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and a retransmit, or between two retransmits.
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Retransmits are triggered by ACKs or timers. So this commit checks
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for bubbles of app-limited silence upon ACKs or timers.
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Why does this commit check for app-limited state at the start of
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ACKs and timer handling? Because at that point we know whether
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inflight was fully using the cwnd. During processing the ACK or
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timer event we often change the cwnd; after changing the cwnd we
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can't know whether inflight was fully using the old cwnd.
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Origin-9xx-SHA1: 3fe9b53291e018407780fb8c356adb5666722cbc
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Change-Id: I37221506f5166877c2b110753d39bb0757985e68
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Signed-off-by: Alexandre Frade <kernel@xanmod.org>
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---
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net/ipv4/tcp_input.c | 1 +
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net/ipv4/tcp_timer.c | 1 +
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2 files changed, 2 insertions(+)
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--- a/net/ipv4/tcp_input.c
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+++ b/net/ipv4/tcp_input.c
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@@ -3961,6 +3961,7 @@ static int tcp_ack(struct sock *sk, cons
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prior_fack = tcp_is_sack(tp) ? tcp_highest_sack_seq(tp) : tp->snd_una;
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rs.prior_in_flight = tcp_packets_in_flight(tp);
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+ tcp_rate_check_app_limited(sk);
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/* ts_recent update must be made after we are sure that the packet
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* is in window.
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--- a/net/ipv4/tcp_timer.c
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+++ b/net/ipv4/tcp_timer.c
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@@ -689,6 +689,7 @@ void tcp_write_timer_handler(struct sock
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return;
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}
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+ tcp_rate_check_app_limited(sk);
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tcp_mstamp_refresh(tcp_sk(sk));
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event = icsk->icsk_pending;
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