1 /* Tom Kelly's Scalable TCP
3 * See http://www.deneholme.net/tom/scalable/
5 * John Heffner <jheffner@sc.edu>
8 #include <linux/module.h>
11 /* These factors derived from the recommended values in the aer:
12 * .01 and and 7/8. We use 50 instead of 100 to account for
15 #define TCP_SCALABLE_AI_CNT 50U
16 #define TCP_SCALABLE_MD_SCALE 3
18 static void tcp_scalable_cong_avoid(struct sock
*sk
, u32 ack
, u32 acked
,
21 struct tcp_sock
*tp
= tcp_sk(sk
);
23 if (!tcp_is_cwnd_limited(sk
, in_flight
))
26 if (tp
->snd_cwnd
<= tp
->snd_ssthresh
)
27 tcp_slow_start(tp
, acked
);
29 tcp_cong_avoid_ai(tp
, min(tp
->snd_cwnd
, TCP_SCALABLE_AI_CNT
));
32 static u32
tcp_scalable_ssthresh(struct sock
*sk
)
34 const struct tcp_sock
*tp
= tcp_sk(sk
);
35 return max(tp
->snd_cwnd
- (tp
->snd_cwnd
>>TCP_SCALABLE_MD_SCALE
), 2U);
39 static struct tcp_congestion_ops tcp_scalable __read_mostly
= {
40 .ssthresh
= tcp_scalable_ssthresh
,
41 .cong_avoid
= tcp_scalable_cong_avoid
,
42 .min_cwnd
= tcp_reno_min_cwnd
,
48 static int __init
tcp_scalable_register(void)
50 return tcp_register_congestion_control(&tcp_scalable
);
53 static void __exit
tcp_scalable_unregister(void)
55 tcp_unregister_congestion_control(&tcp_scalable
);
58 module_init(tcp_scalable_register
);
59 module_exit(tcp_scalable_unregister
);
61 MODULE_AUTHOR("John Heffner");
62 MODULE_LICENSE("GPL");
63 MODULE_DESCRIPTION("Scalable TCP");