diff options
Diffstat (limited to 'net/ipv4/tcp_cong.c')
| -rw-r--r-- | net/ipv4/tcp_cong.c | 31 |
1 files changed, 22 insertions, 9 deletions
diff --git a/net/ipv4/tcp_cong.c b/net/ipv4/tcp_cong.c index 34ae3f13483..ccd88407e0c 100644 --- a/net/ipv4/tcp_cong.c +++ b/net/ipv4/tcp_cong.c @@ -12,6 +12,8 @@ #include <linux/list.h> #include <net/tcp.h> +int sysctl_tcp_max_ssthresh = 0; + static DEFINE_SPINLOCK(tcp_cong_list_lock); static LIST_HEAD(tcp_cong_list); @@ -274,10 +276,13 @@ int tcp_set_congestion_control(struct sock *sk, const char *name) /* - * Linear increase during slow start + * Slow start (exponential increase) with + * RFC3742 Limited Slow Start (fast linear increase) support. */ void tcp_slow_start(struct tcp_sock *tp) { + int cnt = 0; + if (sysctl_tcp_abc) { /* RFC3465: Slow Start * TCP sender SHOULD increase cwnd by the number of @@ -286,17 +291,25 @@ void tcp_slow_start(struct tcp_sock *tp) */ 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++; - } } + + if (sysctl_tcp_max_ssthresh > 0 && + tp->snd_cwnd > sysctl_tcp_max_ssthresh) + cnt += sysctl_tcp_max_ssthresh>>1; + else + cnt += tp->snd_cwnd; + + /* RFC3465: We MAY increase by 2 if discovered delayed ack */ + if (sysctl_tcp_abc > 1 && tp->bytes_acked >= 2*tp->mss_cache) + cnt <<= 1; tp->bytes_acked = 0; - if (tp->snd_cwnd < tp->snd_cwnd_clamp) - tp->snd_cwnd++; + tp->snd_cwnd_cnt += cnt; + while (tp->snd_cwnd_cnt >= tp->snd_cwnd) { + tp->snd_cwnd_cnt -= tp->snd_cwnd; + if (tp->snd_cwnd < tp->snd_cwnd_clamp) + tp->snd_cwnd++; + } } EXPORT_SYMBOL_GPL(tcp_slow_start); |