mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-12-15 23:14:31 +08:00
03fba04796
Reuse limited slow-start (RFC3742) included into tcp_cong instead of having another implementation in High Speed TCP. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
189 lines
4.9 KiB
C
189 lines
4.9 KiB
C
/*
|
|
* Sally Floyd's High Speed TCP (RFC 3649) congestion control
|
|
*
|
|
* See http://www.icir.org/floyd/hstcp.html
|
|
*
|
|
* John Heffner <jheffner@psc.edu>
|
|
*/
|
|
|
|
#include <linux/module.h>
|
|
#include <net/tcp.h>
|
|
|
|
|
|
/* From AIMD tables from RFC 3649 appendix B,
|
|
* with fixed-point MD scaled <<8.
|
|
*/
|
|
static const struct hstcp_aimd_val {
|
|
unsigned int cwnd;
|
|
unsigned int md;
|
|
} hstcp_aimd_vals[] = {
|
|
{ 38, 128, /* 0.50 */ },
|
|
{ 118, 112, /* 0.44 */ },
|
|
{ 221, 104, /* 0.41 */ },
|
|
{ 347, 98, /* 0.38 */ },
|
|
{ 495, 93, /* 0.37 */ },
|
|
{ 663, 89, /* 0.35 */ },
|
|
{ 851, 86, /* 0.34 */ },
|
|
{ 1058, 83, /* 0.33 */ },
|
|
{ 1284, 81, /* 0.32 */ },
|
|
{ 1529, 78, /* 0.31 */ },
|
|
{ 1793, 76, /* 0.30 */ },
|
|
{ 2076, 74, /* 0.29 */ },
|
|
{ 2378, 72, /* 0.28 */ },
|
|
{ 2699, 71, /* 0.28 */ },
|
|
{ 3039, 69, /* 0.27 */ },
|
|
{ 3399, 68, /* 0.27 */ },
|
|
{ 3778, 66, /* 0.26 */ },
|
|
{ 4177, 65, /* 0.26 */ },
|
|
{ 4596, 64, /* 0.25 */ },
|
|
{ 5036, 62, /* 0.25 */ },
|
|
{ 5497, 61, /* 0.24 */ },
|
|
{ 5979, 60, /* 0.24 */ },
|
|
{ 6483, 59, /* 0.23 */ },
|
|
{ 7009, 58, /* 0.23 */ },
|
|
{ 7558, 57, /* 0.22 */ },
|
|
{ 8130, 56, /* 0.22 */ },
|
|
{ 8726, 55, /* 0.22 */ },
|
|
{ 9346, 54, /* 0.21 */ },
|
|
{ 9991, 53, /* 0.21 */ },
|
|
{ 10661, 52, /* 0.21 */ },
|
|
{ 11358, 52, /* 0.20 */ },
|
|
{ 12082, 51, /* 0.20 */ },
|
|
{ 12834, 50, /* 0.20 */ },
|
|
{ 13614, 49, /* 0.19 */ },
|
|
{ 14424, 48, /* 0.19 */ },
|
|
{ 15265, 48, /* 0.19 */ },
|
|
{ 16137, 47, /* 0.19 */ },
|
|
{ 17042, 46, /* 0.18 */ },
|
|
{ 17981, 45, /* 0.18 */ },
|
|
{ 18955, 45, /* 0.18 */ },
|
|
{ 19965, 44, /* 0.17 */ },
|
|
{ 21013, 43, /* 0.17 */ },
|
|
{ 22101, 43, /* 0.17 */ },
|
|
{ 23230, 42, /* 0.17 */ },
|
|
{ 24402, 41, /* 0.16 */ },
|
|
{ 25618, 41, /* 0.16 */ },
|
|
{ 26881, 40, /* 0.16 */ },
|
|
{ 28193, 39, /* 0.16 */ },
|
|
{ 29557, 39, /* 0.15 */ },
|
|
{ 30975, 38, /* 0.15 */ },
|
|
{ 32450, 38, /* 0.15 */ },
|
|
{ 33986, 37, /* 0.15 */ },
|
|
{ 35586, 36, /* 0.14 */ },
|
|
{ 37253, 36, /* 0.14 */ },
|
|
{ 38992, 35, /* 0.14 */ },
|
|
{ 40808, 35, /* 0.14 */ },
|
|
{ 42707, 34, /* 0.13 */ },
|
|
{ 44694, 33, /* 0.13 */ },
|
|
{ 46776, 33, /* 0.13 */ },
|
|
{ 48961, 32, /* 0.13 */ },
|
|
{ 51258, 32, /* 0.13 */ },
|
|
{ 53677, 31, /* 0.12 */ },
|
|
{ 56230, 30, /* 0.12 */ },
|
|
{ 58932, 30, /* 0.12 */ },
|
|
{ 61799, 29, /* 0.12 */ },
|
|
{ 64851, 28, /* 0.11 */ },
|
|
{ 68113, 28, /* 0.11 */ },
|
|
{ 71617, 27, /* 0.11 */ },
|
|
{ 75401, 26, /* 0.10 */ },
|
|
{ 79517, 26, /* 0.10 */ },
|
|
{ 84035, 25, /* 0.10 */ },
|
|
{ 89053, 24, /* 0.10 */ },
|
|
};
|
|
|
|
#define HSTCP_AIMD_MAX ARRAY_SIZE(hstcp_aimd_vals)
|
|
|
|
struct hstcp {
|
|
u32 ai;
|
|
};
|
|
|
|
static void hstcp_init(struct sock *sk)
|
|
{
|
|
struct tcp_sock *tp = tcp_sk(sk);
|
|
struct hstcp *ca = inet_csk_ca(sk);
|
|
|
|
ca->ai = 0;
|
|
|
|
/* Ensure the MD arithmetic works. This is somewhat pedantic,
|
|
* since I don't think we will see a cwnd this large. :) */
|
|
tp->snd_cwnd_clamp = min_t(u32, tp->snd_cwnd_clamp, 0xffffffff/128);
|
|
}
|
|
|
|
static void hstcp_cong_avoid(struct sock *sk, u32 adk, u32 rtt,
|
|
u32 in_flight, int data_acked)
|
|
{
|
|
struct tcp_sock *tp = tcp_sk(sk);
|
|
struct hstcp *ca = inet_csk_ca(sk);
|
|
|
|
if (!tcp_is_cwnd_limited(sk, in_flight))
|
|
return;
|
|
|
|
if (tp->snd_cwnd <= tp->snd_ssthresh)
|
|
tcp_slow_start(tp);
|
|
else {
|
|
/* Update AIMD parameters.
|
|
*
|
|
* We want to guarantee that:
|
|
* hstcp_aimd_vals[ca->ai-1].cwnd <
|
|
* snd_cwnd <=
|
|
* hstcp_aimd_vals[ca->ai].cwnd
|
|
*/
|
|
if (tp->snd_cwnd > hstcp_aimd_vals[ca->ai].cwnd) {
|
|
while (tp->snd_cwnd > hstcp_aimd_vals[ca->ai].cwnd &&
|
|
ca->ai < HSTCP_AIMD_MAX - 1)
|
|
ca->ai++;
|
|
} else if (ca->ai && tp->snd_cwnd <= hstcp_aimd_vals[ca->ai-1].cwnd) {
|
|
while (ca->ai && tp->snd_cwnd <= hstcp_aimd_vals[ca->ai-1].cwnd)
|
|
ca->ai--;
|
|
}
|
|
|
|
/* Do additive increase */
|
|
if (tp->snd_cwnd < tp->snd_cwnd_clamp) {
|
|
/* cwnd = cwnd + a(w) / cwnd */
|
|
tp->snd_cwnd_cnt += ca->ai + 1;
|
|
if (tp->snd_cwnd_cnt >= tp->snd_cwnd) {
|
|
tp->snd_cwnd_cnt -= tp->snd_cwnd;
|
|
tp->snd_cwnd++;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
static u32 hstcp_ssthresh(struct sock *sk)
|
|
{
|
|
const struct tcp_sock *tp = tcp_sk(sk);
|
|
const struct hstcp *ca = inet_csk_ca(sk);
|
|
|
|
/* Do multiplicative decrease */
|
|
return max(tp->snd_cwnd - ((tp->snd_cwnd * hstcp_aimd_vals[ca->ai].md) >> 8), 2U);
|
|
}
|
|
|
|
|
|
static struct tcp_congestion_ops tcp_highspeed = {
|
|
.init = hstcp_init,
|
|
.ssthresh = hstcp_ssthresh,
|
|
.cong_avoid = hstcp_cong_avoid,
|
|
.min_cwnd = tcp_reno_min_cwnd,
|
|
|
|
.owner = THIS_MODULE,
|
|
.name = "highspeed"
|
|
};
|
|
|
|
static int __init hstcp_register(void)
|
|
{
|
|
BUILD_BUG_ON(sizeof(struct hstcp) > ICSK_CA_PRIV_SIZE);
|
|
return tcp_register_congestion_control(&tcp_highspeed);
|
|
}
|
|
|
|
static void __exit hstcp_unregister(void)
|
|
{
|
|
tcp_unregister_congestion_control(&tcp_highspeed);
|
|
}
|
|
|
|
module_init(hstcp_register);
|
|
module_exit(hstcp_unregister);
|
|
|
|
MODULE_AUTHOR("John Heffner");
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_DESCRIPTION("High Speed TCP");
|