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| author | Stephen Hemminger <shemminger@osdl.org> | 2005-11-10 17:09:53 -0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2005-11-10 17:09:53 -0800 |
| commit | 9772efb970780aeed488c19d8b4afd46c3b484af (patch) | |
| tree | de016aaa29c8a95e98c7abaa70c8b590160e2886 /include | |
| parent | 7faffa1c7fb9b8e8917e3225d4e2638270c0a48b (diff) | |
| download | lwn-9772efb970780aeed488c19d8b4afd46c3b484af.tar.gz lwn-9772efb970780aeed488c19d8b4afd46c3b484af.zip | |
[TCP]: Appropriate Byte Count support
This is an updated version of the RFC3465 ABC patch originally
for Linux 2.6.11-rc4 by Yee-Ting Li. ABC is a way of counting
bytes ack'd rather than packets when updating congestion control.
The orignal ABC described in the RFC applied to a Reno style
algorithm. For advanced congestion control there is little
change after leaving slow start.
Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/sysctl.h | 1 | ||||
| -rw-r--r-- | include/linux/tcp.h | 1 | ||||
| -rw-r--r-- | include/net/tcp.h | 19 |
3 files changed, 21 insertions, 0 deletions
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h index 22cf5e1ac987..ab2791b3189d 100644 --- a/include/linux/sysctl.h +++ b/include/linux/sysctl.h @@ -390,6 +390,7 @@ enum NET_TCP_BIC_BETA=108, NET_IPV4_ICMP_ERRORS_USE_INBOUND_IFADDR=109, NET_TCP_CONG_CONTROL=110, + NET_TCP_ABC=111, }; enum { diff --git a/include/linux/tcp.h b/include/linux/tcp.h index ac4ca44c75ca..737b32e52956 100644 --- a/include/linux/tcp.h +++ b/include/linux/tcp.h @@ -326,6 +326,7 @@ struct tcp_sock { __u32 snd_up; /* Urgent pointer */ __u32 total_retrans; /* Total retransmits for entire connection */ + __u32 bytes_acked; /* Appropriate Byte Counting - RFC3465 */ unsigned int keepalive_time; /* time before keep alive takes place */ unsigned int keepalive_intvl; /* time interval between keep alive probes */ diff --git a/include/net/tcp.h b/include/net/tcp.h index 54c399886275..44ba4a21cbdc 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -218,6 +218,7 @@ extern int sysctl_tcp_low_latency; extern int sysctl_tcp_nometrics_save; extern int sysctl_tcp_moderate_rcvbuf; extern int sysctl_tcp_tso_win_divisor; +extern int sysctl_tcp_abc; extern atomic_t tcp_memory_allocated; extern atomic_t tcp_sockets_allocated; @@ -770,6 +771,23 @@ static inline __u32 tcp_current_ssthresh(const struct sock *sk) */ static inline void tcp_slow_start(struct tcp_sock *tp) { + if (sysctl_tcp_abc) { + /* RFC3465: Slow Start + * TCP sender SHOULD increase cwnd by the number of + * previously unacknowledged bytes ACKed by each incoming + * acknowledgment, provided the increase is not more than L + */ + if (tp->bytes_acked < tp->mss_cache) + return; + + /* We MAY increase by 2 if discovered delayed ack */ + if (sysctl_tcp_abc > 1 && tp->bytes_acked > 2*tp->mss_cache) { + if (tp->snd_cwnd < tp->snd_cwnd_clamp) + tp->snd_cwnd++; + } + } + tp->bytes_acked = 0; + if (tp->snd_cwnd < tp->snd_cwnd_clamp) tp->snd_cwnd++; } @@ -804,6 +822,7 @@ static inline void tcp_enter_cwr(struct sock *sk) struct tcp_sock *tp = tcp_sk(sk); tp->prior_ssthresh = 0; + tp->bytes_acked = 0; if (inet_csk(sk)->icsk_ca_state < TCP_CA_CWR) { __tcp_enter_cwr(sk); tcp_set_ca_state(sk, TCP_CA_CWR); |