cregit-Linux how code gets into the kernel

Release 4.8 net/ipv4/tcp_highspeed.c

Directory: net/ipv4
/*
 * 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); }

Contributors

PersonTokensPropCommitsCommitProp
john heffnerjohn heffner4174.55%150.00%
arnaldo carvalho de meloarnaldo carvalho de melo1425.45%150.00%
Total55100.00%2100.00%


static void hstcp_cong_avoid(struct sock *sk, u32 ack, u32 acked) { struct tcp_sock *tp = tcp_sk(sk); struct hstcp *ca = inet_csk_ca(sk); if (!tcp_is_cwnd_limited(sk)) return; if (tcp_in_slow_start(tp)) tcp_slow_start(tp, acked); 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++; } } } }

Contributors

PersonTokensPropCommitsCommitProp
john heffnerjohn heffner15775.48%218.18%
wei (david) xiaoliangwei (david) xiaoliang157.21%19.09%
arnaldo carvalho de meloarnaldo carvalho de melo146.73%19.09%
stephen hemmingerstephen hemminger104.81%327.27%
yuchung chengyuchung cheng94.33%218.18%
patrick mchardypatrick mchardy20.96%19.09%
ilpo jarvinenilpo jarvinen10.48%19.09%
Total208100.00%11100.00%


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); }

Contributors

PersonTokensPropCommitsCommitProp
john heffnerjohn heffner4774.60%150.00%
arnaldo carvalho de meloarnaldo carvalho de melo1625.40%150.00%
Total63100.00%2100.00%

static struct tcp_congestion_ops tcp_highspeed __read_mostly = { .init = hstcp_init, .ssthresh = hstcp_ssthresh, .cong_avoid = hstcp_cong_avoid, .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); }

Contributors

PersonTokensPropCommitsCommitProp
john heffnerjohn heffner2592.59%133.33%
arnaldo carvalho de meloarnaldo carvalho de melo13.70%133.33%
alexey dobriyanalexey dobriyan13.70%133.33%
Total27100.00%3100.00%


static void __exit hstcp_unregister(void) { tcp_unregister_congestion_control(&tcp_highspeed); }

Contributors

PersonTokensPropCommitsCommitProp
john heffnerjohn heffner15100.00%1100.00%
Total15100.00%1100.00%

module_init(hstcp_register); module_exit(hstcp_unregister); MODULE_AUTHOR("John Heffner"); MODULE_LICENSE("GPL"); MODULE_DESCRIPTION("High Speed TCP");

Overall Contributors

PersonTokensPropCommitsCommitProp
john heffnerjohn heffner95791.93%215.38%
arnaldo carvalho de meloarnaldo carvalho de melo454.32%17.69%
wei (david) xiaoliangwei (david) xiaoliang151.44%17.69%
stephen hemmingerstephen hemminger111.06%430.77%
yuchung chengyuchung cheng90.86%215.38%
patrick mchardypatrick mchardy20.19%17.69%
alexey dobriyanalexey dobriyan10.10%17.69%
ilpo jarvinenilpo jarvinen10.10%17.69%
Total1041100.00%13100.00%
Directory: net/ipv4
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