diff options
| author | David S. Miller <davem@davemloft.net> | 2017-01-14 06:37:18 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-01-14 06:37:18 +0300 |
| commit | 718e14bb292a2e16b506133d191886110417df51 (patch) | |
| tree | a889a29b8bbad8c1c64d339273bcdeea67d63299 /net/ipv4/tcp.c | |
| parent | 7410191afcaca3a49bb29bfb5e15f81d7b336984 (diff) | |
| parent | 94bdc9785a1136cef6a982b042719783978e8a26 (diff) | |
| download | linux-718e14bb292a2e16b506133d191886110417df51.tar.xz | |
Merge branch 'tcp-RACK-fast-recovery'
Yuchung Cheng says:
====================
tcp: RACK fast recovery
The patch set enables RACK loss detection (draft-ietf-tcpm-rack-01)
to trigger fast recovery with a reordering timer.
Previously RACK has been running in auxiliary mode where it is
used to detect packet losses once the recovery has triggered by
other algorithms (e.g., FACK). By inspecting packet timestamps,
RACK can start ACK-driven repairs timely. A few similar heuristics
are no longer needed and are either removed or disabled to reduce
the complexity of the Linux TCP loss recovery engine:
1. FACK (Forward Acknowledgement)
2. Early Retransmit (RFC5827)
3. thin_dupack (fast recovery on single DUPACK for thin-streams)
4. NCR (Non-Congestion Robustness RFC4653) (RFC4653)
5. Forward Retransmit
After this change, Linux's loss recovery algorithms consist of
1. Conventional DUPACK threshold approach (RFC6675)
2. RACK and Tail Loss Probe (draft-ietf-tcpm-rack-01)
3. RTO plus F-RTO extension (RFC5682)
The patch set has been tested on Google servers extensively and
presented in several IETF meetings. The data suggests that RACK
successfully improves recovery performance:
https://www.ietf.org/proceedings/97/slides/slides-97-tcpm-draft-ietf-tcpm-rack-01.pdf
https://www.ietf.org/proceedings/96/slides/slides-96-tcpm-3.pdf
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp.c')
| -rw-r--r-- | net/ipv4/tcp.c | 9 |
1 files changed, 2 insertions, 7 deletions
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index c8d46c140b4a..aba6ea76338e 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -406,7 +406,6 @@ void tcp_init_sock(struct sock *sk) tp->mss_cache = TCP_MSS_DEFAULT; tp->reordering = sock_net(sk)->ipv4.sysctl_tcp_reordering; - tcp_enable_early_retrans(tp); tcp_assign_congestion_control(sk); tp->tsoffset = 0; @@ -2475,11 +2474,6 @@ static int do_tcp_setsockopt(struct sock *sk, int level, case TCP_THIN_DUPACK: if (val < 0 || val > 1) err = -EINVAL; - else { - tp->thin_dupack = val; - if (tp->thin_dupack) - tcp_disable_early_retrans(tp); - } break; case TCP_REPAIR: @@ -2969,8 +2963,9 @@ static int do_tcp_getsockopt(struct sock *sk, int level, case TCP_THIN_LINEAR_TIMEOUTS: val = tp->thin_lto; break; + case TCP_THIN_DUPACK: - val = tp->thin_dupack; + val = 0; break; case TCP_REPAIR: |