diff options
Diffstat (limited to 'net')
| -rw-r--r-- | net/ipv4/Kconfig | 9 | ||||
| -rw-r--r-- | net/ipv4/Makefile | 1 | ||||
| -rw-r--r-- | net/ipv4/tcp_scalable.c | 68 |
3 files changed, 78 insertions, 0 deletions
diff --git a/net/ipv4/Kconfig b/net/ipv4/Kconfig index 73a25b52bf7d..690e88ba2484 100644 --- a/net/ipv4/Kconfig +++ b/net/ipv4/Kconfig @@ -511,6 +511,15 @@ config TCP_CONG_VEGAS window. TCP Vegas should provide less packet loss, but it is not as aggressive as TCP Reno. +config TCP_CONG_SCALABLE + tristate "Scalable TCP" + depends on INET && EXPERIMENTAL + default n + ---help--- + Scalable TCP is a sender-side only change to TCP which uses a + MIMD congestion control algorithm which has some nice scaling + properties, though is known to have fairness issues. + See http://www-lce.eng.cam.ac.uk/~ctk21/scalable/ endmenu diff --git a/net/ipv4/Makefile b/net/ipv4/Makefile index e96ed17deb96..5718cdb3a61e 100644 --- a/net/ipv4/Makefile +++ b/net/ipv4/Makefile @@ -37,6 +37,7 @@ obj-$(CONFIG_TCP_CONG_HSTCP) += tcp_highspeed.o obj-$(CONFIG_TCP_CONG_HYBLA) += tcp_hybla.o obj-$(CONFIG_TCP_CONG_HTCP) += tcp_htcp.o obj-$(CONFIG_TCP_CONG_VEGAS) += tcp_vegas.o +obj-$(CONFIG_TCP_CONG_SCALABLE) += tcp_scalable.o obj-$(CONFIG_XFRM) += xfrm4_policy.o xfrm4_state.o xfrm4_input.o \ xfrm4_output.o diff --git a/net/ipv4/tcp_scalable.c b/net/ipv4/tcp_scalable.c new file mode 100644 index 000000000000..70e108e15c71 --- /dev/null +++ b/net/ipv4/tcp_scalable.c @@ -0,0 +1,68 @@ +/* Tom Kelly's Scalable TCP + * + * See htt://www-lce.eng.cam.ac.uk/~ctk21/scalable/ + * + * John Heffner <jheffner@sc.edu> + */ + +#include <linux/config.h> +#include <linux/module.h> +#include <net/tcp.h> + +/* These factors derived from the recommended values in the aer: + * .01 and and 7/8. We use 50 instead of 100 to account for + * delayed ack. + */ +#define TCP_SCALABLE_AI_CNT 50U +#define TCP_SCALABLE_MD_SCALE 3 + +static void tcp_scalable_cong_avoid(struct tcp_sock *tp, u32 ack, u32 rtt, + u32 in_flight, int flag) +{ + if (in_flight < tp->snd_cwnd) + return; + + if (tp->snd_cwnd <= tp->snd_ssthresh) { + tp->snd_cwnd++; + } else { + tp->snd_cwnd_cnt++; + if (tp->snd_cwnd_cnt > min(tp->snd_cwnd, TCP_SCALABLE_AI_CNT)){ + tp->snd_cwnd++; + tp->snd_cwnd_cnt = 0; + } + } + tp->snd_cwnd = min_t(u32, tp->snd_cwnd, tp->snd_cwnd_clamp); + tp->snd_cwnd_stamp = tcp_time_stamp; +} + +static u32 tcp_scalable_ssthresh(struct tcp_sock *tp) +{ + return max(tp->snd_cwnd - (tp->snd_cwnd>>TCP_SCALABLE_MD_SCALE), 2U); +} + + +static struct tcp_congestion_ops tcp_scalable = { + .ssthresh = tcp_scalable_ssthresh, + .cong_avoid = tcp_scalable_cong_avoid, + .min_cwnd = tcp_reno_min_cwnd, + + .owner = THIS_MODULE, + .name = "scalable", +}; + +static int __init tcp_scalable_register(void) +{ + return tcp_register_congestion_control(&tcp_scalable); +} + +static void __exit tcp_scalable_unregister(void) +{ + tcp_unregister_congestion_control(&tcp_scalable); +} + +module_init(tcp_scalable_register); +module_exit(tcp_scalable_unregister); + +MODULE_AUTHOR("John Heffner"); +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("Scalable TCP"); |