diff options
| author | Florian Westphal <fw@strlen.de> | 2014-09-26 22:37:34 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2014-09-29 06:13:10 +0200 |
| commit | 7354c8c389d18719dd71cc810da70b0921d66694 (patch) | |
| tree | 776fa6ce824557d0c8bbf4271ad3b08a4832a66f /net/ipv4/tcp_westwood.c | |
| parent | net: tcp: add flag for ca to indicate that ECN is required (diff) | |
| download | linux-7354c8c389d18719dd71cc810da70b0921d66694.tar.xz linux-7354c8c389d18719dd71cc810da70b0921d66694.zip | |
net: tcp: split ack slow/fast events from cwnd_event
The congestion control ops "cwnd_event" currently supports
CA_EVENT_FAST_ACK and CA_EVENT_SLOW_ACK events (among others).
Both FAST and SLOW_ACK are only used by Westwood congestion
control algorithm.
This removes both flags from cwnd_event and adds a new
in_ack_event callback for this. The goal is to be able to
provide more detailed information about ACKs, such as whether
ECE flag was set, or whether the ACK resulted in a window
update.
It is required for DataCenter TCP (DCTCP) congestion control
algorithm as it makes a different choice depending on ECE being
set or not.
Joint work with Daniel Borkmann and Glenn Judd.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: Glenn Judd <glenn.judd@morganstanley.com>
Acked-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp_westwood.c')
| -rw-r--r-- | net/ipv4/tcp_westwood.c | 28 |
1 files changed, 16 insertions, 12 deletions
diff --git a/net/ipv4/tcp_westwood.c b/net/ipv4/tcp_westwood.c index 81911a92356c..bb63fba47d47 100644 --- a/net/ipv4/tcp_westwood.c +++ b/net/ipv4/tcp_westwood.c @@ -220,32 +220,35 @@ static u32 tcp_westwood_bw_rttmin(const struct sock *sk) return max_t(u32, (w->bw_est * w->rtt_min) / tp->mss_cache, 2); } +static void tcp_westwood_ack(struct sock *sk, u32 ack_flags) +{ + if (ack_flags & CA_ACK_SLOWPATH) { + struct westwood *w = inet_csk_ca(sk); + + westwood_update_window(sk); + w->bk += westwood_acked_count(sk); + + update_rtt_min(w); + return; + } + + westwood_fast_bw(sk); +} + static void tcp_westwood_event(struct sock *sk, enum tcp_ca_event event) { struct tcp_sock *tp = tcp_sk(sk); struct westwood *w = inet_csk_ca(sk); switch (event) { - case CA_EVENT_FAST_ACK: - westwood_fast_bw(sk); - break; - case CA_EVENT_COMPLETE_CWR: tp->snd_cwnd = tp->snd_ssthresh = tcp_westwood_bw_rttmin(sk); break; - case CA_EVENT_LOSS: tp->snd_ssthresh = tcp_westwood_bw_rttmin(sk); /* Update RTT_min when next ack arrives */ w->reset_rtt_min = 1; break; - - case CA_EVENT_SLOW_ACK: - westwood_update_window(sk); - w->bk += westwood_acked_count(sk); - update_rtt_min(w); - break; - default: /* don't care */ break; @@ -274,6 +277,7 @@ static struct tcp_congestion_ops tcp_westwood __read_mostly = { .ssthresh = tcp_reno_ssthresh, .cong_avoid = tcp_reno_cong_avoid, .cwnd_event = tcp_westwood_event, + .in_ack_event = tcp_westwood_ack, .get_info = tcp_westwood_info, .pkts_acked = tcp_westwood_pkts_acked, |