diff options
Diffstat (limited to 'net/ipv4/tcp_cubic.c')
-rw-r--r-- | net/ipv4/tcp_cubic.c | 35 |
1 files changed, 8 insertions, 27 deletions
diff --git a/net/ipv4/tcp_cubic.c b/net/ipv4/tcp_cubic.c index 3aa0b23c1ea0..eb5b9854c8c7 100644 --- a/net/ipv4/tcp_cubic.c +++ b/net/ipv4/tcp_cubic.c | |||
@@ -1,12 +1,13 @@ | |||
1 | /* | 1 | /* |
2 | * TCP CUBIC: Binary Increase Congestion control for TCP v2.1 | 2 | * TCP CUBIC: Binary Increase Congestion control for TCP v2.2 |
3 | * | 3 | * Home page: |
4 | * http://netsrv.csc.ncsu.edu/twiki/bin/view/Main/BIC | ||
4 | * This is from the implementation of CUBIC TCP in | 5 | * This is from the implementation of CUBIC TCP in |
5 | * Injong Rhee, Lisong Xu. | 6 | * Injong Rhee, Lisong Xu. |
6 | * "CUBIC: A New TCP-Friendly High-Speed TCP Variant | 7 | * "CUBIC: A New TCP-Friendly High-Speed TCP Variant |
7 | * in PFLDnet 2005 | 8 | * in PFLDnet 2005 |
8 | * Available from: | 9 | * Available from: |
9 | * http://www.csc.ncsu.edu/faculty/rhee/export/bitcp/cubic-paper.pdf | 10 | * http://netsrv.csc.ncsu.edu/export/cubic-paper.pdf |
10 | * | 11 | * |
11 | * Unless CUBIC is enabled and congestion window is large | 12 | * Unless CUBIC is enabled and congestion window is large |
12 | * this behaves the same as the original Reno. | 13 | * this behaves the same as the original Reno. |
@@ -20,15 +21,10 @@ | |||
20 | #define BICTCP_BETA_SCALE 1024 /* Scale factor beta calculation | 21 | #define BICTCP_BETA_SCALE 1024 /* Scale factor beta calculation |
21 | * max_cwnd = snd_cwnd * beta | 22 | * max_cwnd = snd_cwnd * beta |
22 | */ | 23 | */ |
23 | #define BICTCP_B 4 /* | ||
24 | * In binary search, | ||
25 | * go to point (max+min)/N | ||
26 | */ | ||
27 | #define BICTCP_HZ 10 /* BIC HZ 2^10 = 1024 */ | 24 | #define BICTCP_HZ 10 /* BIC HZ 2^10 = 1024 */ |
28 | 25 | ||
29 | static int fast_convergence __read_mostly = 1; | 26 | static int fast_convergence __read_mostly = 1; |
30 | static int max_increment __read_mostly = 16; | 27 | static int beta __read_mostly = 717; /* = 717/1024 (BICTCP_BETA_SCALE) */ |
31 | static int beta __read_mostly = 819; /* = 819/1024 (BICTCP_BETA_SCALE) */ | ||
32 | static int initial_ssthresh __read_mostly; | 28 | static int initial_ssthresh __read_mostly; |
33 | static int bic_scale __read_mostly = 41; | 29 | static int bic_scale __read_mostly = 41; |
34 | static int tcp_friendliness __read_mostly = 1; | 30 | static int tcp_friendliness __read_mostly = 1; |
@@ -40,9 +36,7 @@ static u64 cube_factor __read_mostly; | |||
40 | /* Note parameters that are used for precomputing scale factors are read-only */ | 36 | /* Note parameters that are used for precomputing scale factors are read-only */ |
41 | module_param(fast_convergence, int, 0644); | 37 | module_param(fast_convergence, int, 0644); |
42 | MODULE_PARM_DESC(fast_convergence, "turn on/off fast convergence"); | 38 | MODULE_PARM_DESC(fast_convergence, "turn on/off fast convergence"); |
43 | module_param(max_increment, int, 0644); | 39 | module_param(beta, int, 0644); |
44 | MODULE_PARM_DESC(max_increment, "Limit on increment allowed during binary search"); | ||
45 | module_param(beta, int, 0444); | ||
46 | MODULE_PARM_DESC(beta, "beta for multiplicative increase"); | 40 | MODULE_PARM_DESC(beta, "beta for multiplicative increase"); |
47 | module_param(initial_ssthresh, int, 0644); | 41 | module_param(initial_ssthresh, int, 0644); |
48 | MODULE_PARM_DESC(initial_ssthresh, "initial value of slow start threshold"); | 42 | MODULE_PARM_DESC(initial_ssthresh, "initial value of slow start threshold"); |
@@ -145,7 +139,7 @@ static u32 cubic_root(u64 a) | |||
145 | static inline void bictcp_update(struct bictcp *ca, u32 cwnd) | 139 | static inline void bictcp_update(struct bictcp *ca, u32 cwnd) |
146 | { | 140 | { |
147 | u64 offs; | 141 | u64 offs; |
148 | u32 delta, t, bic_target, min_cnt, max_cnt; | 142 | u32 delta, t, bic_target, max_cnt; |
149 | 143 | ||
150 | ca->ack_cnt++; /* count the number of ACKs */ | 144 | ca->ack_cnt++; /* count the number of ACKs */ |
151 | 145 | ||
@@ -211,19 +205,6 @@ static inline void bictcp_update(struct bictcp *ca, u32 cwnd) | |||
211 | ca->cnt = 100 * cwnd; /* very small increment*/ | 205 | ca->cnt = 100 * cwnd; /* very small increment*/ |
212 | } | 206 | } |
213 | 207 | ||
214 | if (ca->delay_min > 0) { | ||
215 | /* max increment = Smax * rtt / 0.1 */ | ||
216 | min_cnt = (cwnd * HZ * 8)/(10 * max_increment * ca->delay_min); | ||
217 | |||
218 | /* use concave growth when the target is above the origin */ | ||
219 | if (ca->cnt < min_cnt && t >= ca->bic_K) | ||
220 | ca->cnt = min_cnt; | ||
221 | } | ||
222 | |||
223 | /* slow start and low utilization */ | ||
224 | if (ca->loss_cwnd == 0) /* could be aggressive in slow start */ | ||
225 | ca->cnt = 50; | ||
226 | |||
227 | /* TCP Friendly */ | 208 | /* TCP Friendly */ |
228 | if (tcp_friendliness) { | 209 | if (tcp_friendliness) { |
229 | u32 scale = beta_scale; | 210 | u32 scale = beta_scale; |
@@ -391,4 +372,4 @@ module_exit(cubictcp_unregister); | |||
391 | MODULE_AUTHOR("Sangtae Ha, Stephen Hemminger"); | 372 | MODULE_AUTHOR("Sangtae Ha, Stephen Hemminger"); |
392 | MODULE_LICENSE("GPL"); | 373 | MODULE_LICENSE("GPL"); |
393 | MODULE_DESCRIPTION("CUBIC TCP"); | 374 | MODULE_DESCRIPTION("CUBIC TCP"); |
394 | MODULE_VERSION("2.1"); | 375 | MODULE_VERSION("2.2"); |