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sys/netinet/cc/cc_cubic.c
Show First 20 Lines • Show All 64 Lines • ▼ Show 20 Lines | |||||
#include <net/route.h> | #include <net/route.h> | ||||
#include <net/route/nhop.h> | #include <net/route/nhop.h> | ||||
#include <netinet/in_pcb.h> | #include <netinet/in_pcb.h> | ||||
#include <netinet/tcp.h> | #include <netinet/tcp.h> | ||||
#include <netinet/tcp_seq.h> | #include <netinet/tcp_seq.h> | ||||
#include <netinet/tcp_timer.h> | #include <netinet/tcp_timer.h> | ||||
#include <netinet/tcp_var.h> | #include <netinet/tcp_var.h> | ||||
#include <netinet/tcp_log_buf.h> | |||||
#include <netinet/tcp_hpts.h> | |||||
#include <netinet/cc/cc.h> | #include <netinet/cc/cc.h> | ||||
#include <netinet/cc/cc_cubic.h> | #include <netinet/cc/cc_cubic.h> | ||||
#include <netinet/cc/cc_module.h> | #include <netinet/cc/cc_module.h> | ||||
static void cubic_ack_received(struct cc_var *ccv, uint16_t type); | static void cubic_ack_received(struct cc_var *ccv, uint16_t type); | ||||
static void cubic_cb_destroy(struct cc_var *ccv); | static void cubic_cb_destroy(struct cc_var *ccv); | ||||
static int cubic_cb_init(struct cc_var *ccv, void *ptr); | static int cubic_cb_init(struct cc_var *ccv, void *ptr); | ||||
static void cubic_cong_signal(struct cc_var *ccv, uint32_t type); | static void cubic_cong_signal(struct cc_var *ccv, uint32_t type); | ||||
static void cubic_conn_init(struct cc_var *ccv); | static void cubic_conn_init(struct cc_var *ccv); | ||||
static int cubic_mod_init(void); | static int cubic_mod_init(void); | ||||
static void cubic_post_recovery(struct cc_var *ccv); | static void cubic_post_recovery(struct cc_var *ccv); | ||||
static void cubic_record_rtt(struct cc_var *ccv); | static void cubic_record_rtt(struct cc_var *ccv); | ||||
static void cubic_ssthresh_update(struct cc_var *ccv, uint32_t maxseg); | static void cubic_ssthresh_update(struct cc_var *ccv, uint32_t maxseg); | ||||
static void cubic_after_idle(struct cc_var *ccv); | static void cubic_after_idle(struct cc_var *ccv); | ||||
static size_t cubic_data_sz(void); | static size_t cubic_data_sz(void); | ||||
static void cubic_newround(struct cc_var *ccv, uint32_t round_cnt); | |||||
static void cubic_rttsample(struct cc_var *ccv, uint32_t usec_rtt, | |||||
uint32_t rxtcnt, uint32_t fas); | |||||
struct cubic { | |||||
/* Cubic K in fixed point form with CUBIC_SHIFT worth of precision. */ | |||||
int64_t K; | |||||
/* Sum of RTT samples across an epoch in ticks. */ | |||||
int64_t sum_rtt_ticks; | |||||
/* cwnd at the most recent congestion event. */ | |||||
unsigned long max_cwnd; | |||||
/* cwnd at the previous congestion event. */ | |||||
unsigned long prev_max_cwnd; | |||||
/* A copy of prev_max_cwnd. Used for CC_RTO_ERR */ | |||||
unsigned long prev_max_cwnd_cp; | |||||
/* various flags */ | |||||
uint32_t flags; | |||||
#define CUBICFLAG_CONG_EVENT 0x00000001 /* congestion experienced */ | |||||
#define CUBICFLAG_IN_SLOWSTART 0x00000002 /* in slow start */ | |||||
#define CUBICFLAG_IN_APPLIMIT 0x00000004 /* application limited */ | |||||
#define CUBICFLAG_RTO_EVENT 0x00000008 /* RTO experienced */ | |||||
/* Minimum observed rtt in ticks. */ | |||||
int min_rtt_ticks; | |||||
/* Mean observed rtt between congestion epochs. */ | |||||
int mean_rtt_ticks; | |||||
/* ACKs since last congestion event. */ | |||||
int epoch_ack_count; | |||||
/* Timestamp (in ticks) of arriving in congestion avoidance from last | |||||
* congestion event. | |||||
*/ | |||||
int t_last_cong; | |||||
/* Timestamp (in ticks) of a previous congestion event. Used for | |||||
* CC_RTO_ERR. | |||||
*/ | |||||
int t_last_cong_prev; | |||||
}; | |||||
struct cc_algo cubic_cc_algo = { | struct cc_algo cubic_cc_algo = { | ||||
.name = "cubic", | .name = "cubic", | ||||
.ack_received = cubic_ack_received, | .ack_received = cubic_ack_received, | ||||
.cb_destroy = cubic_cb_destroy, | .cb_destroy = cubic_cb_destroy, | ||||
.cb_init = cubic_cb_init, | .cb_init = cubic_cb_init, | ||||
.cong_signal = cubic_cong_signal, | .cong_signal = cubic_cong_signal, | ||||
.conn_init = cubic_conn_init, | .conn_init = cubic_conn_init, | ||||
.mod_init = cubic_mod_init, | .mod_init = cubic_mod_init, | ||||
.post_recovery = cubic_post_recovery, | .post_recovery = cubic_post_recovery, | ||||
.after_idle = cubic_after_idle, | .after_idle = cubic_after_idle, | ||||
.cc_data_sz = cubic_data_sz | .cc_data_sz = cubic_data_sz, | ||||
.rttsample = cubic_rttsample, | |||||
.newround = cubic_newround | |||||
}; | }; | ||||
static void | static void | ||||
cubic_log_hystart_event(struct cc_var *ccv, struct cubic *cubicd, uint8_t mod, uint32_t flex1) | |||||
{ | |||||
/* | |||||
* Types of logs (mod value) | |||||
* 1 - rtt_thresh in flex1, checking to see if RTT is to great. | |||||
* 2 - rtt is too great, rtt_thresh in flex1. | |||||
* 3 - CSS is active incr in flex1 | |||||
* 4 - A new round is beginning flex1 is round count | |||||
* 5 - A new RTT measurement flex1 is the new measurement. | |||||
* 6 - We enter CA ssthresh is also in flex1. | |||||
* 7 - Socket option to change hystart executed opt.val in flex1. | |||||
* 8 - Back out of CSS into SS, flex1 is the css_baseline_minrtt | |||||
* 9 - We enter CA, via an ECN mark. | |||||
* 10 - We enter CA, via a loss. | |||||
* 11 - We have slipped out of SS into CA via cwnd growth. | |||||
* 12 - After idle has re-enabled hystart++ | |||||
*/ | |||||
struct tcpcb *tp; | |||||
if (hystart_bblogs == 0) | |||||
return; | |||||
tp = ccv->ccvc.tcp; | |||||
if (tp->t_logstate != TCP_LOG_STATE_OFF) { | |||||
union tcp_log_stackspecific log; | |||||
struct timeval tv; | |||||
memset(&log, 0, sizeof(log)); | |||||
log.u_bbr.flex1 = flex1; | |||||
log.u_bbr.flex2 = cubicd->css_current_round_minrtt; | |||||
log.u_bbr.flex3 = cubicd->css_lastround_minrtt; | |||||
log.u_bbr.flex4 = cubicd->css_rttsample_count; | |||||
log.u_bbr.flex5 = cubicd->css_entered_at_round; | |||||
log.u_bbr.flex6 = cubicd->css_baseline_minrtt; | |||||
/* We only need bottom 16 bits of flags */ | |||||
log.u_bbr.flex7 = cubicd->flags & 0x0000ffff; | |||||
log.u_bbr.flex8 = mod; | |||||
log.u_bbr.epoch = cubicd->css_current_round; | |||||
log.u_bbr.timeStamp = tcp_get_usecs(&tv); | |||||
log.u_bbr.lt_epoch = cubicd->css_fas_at_css_entry; | |||||
log.u_bbr.pkts_out = cubicd->css_last_fas; | |||||
log.u_bbr.delivered = cubicd->css_lowrtt_fas; | |||||
log.u_bbr.pkt_epoch = ccv->flags; | |||||
TCP_LOG_EVENTP(tp, NULL, | |||||
&tp->t_inpcb->inp_socket->so_rcv, | |||||
&tp->t_inpcb->inp_socket->so_snd, | |||||
TCP_HYSTART, 0, | |||||
0, &log, false, &tv); | |||||
} | |||||
} | |||||
static void | |||||
cubic_does_slow_start(struct cc_var *ccv, struct cubic *cubicd) | |||||
{ | |||||
/* | |||||
* In slow-start with ABC enabled and no RTO in sight? | |||||
* (Must not use abc_l_var > 1 if slow starting after | |||||
* an RTO. On RTO, snd_nxt = snd_una, so the | |||||
* snd_nxt == snd_max check is sufficient to | |||||
* handle this). | |||||
* | |||||
* XXXLAS: Find a way to signal SS after RTO that | |||||
* doesn't rely on tcpcb vars. | |||||
*/ | |||||
u_int cw = CCV(ccv, snd_cwnd); | |||||
u_int incr = CCV(ccv, t_maxseg); | |||||
cc: Like a mss is used in cubic_cong_signal(), and as ABC is involved, for accurate calculation… | |||||
uint16_t abc_val; | |||||
cubicd->flags |= CUBICFLAG_IN_SLOWSTART; | |||||
if (ccv->flags & CCF_USE_LOCAL_ABC) | |||||
abc_val = ccv->labc; | |||||
else | |||||
abc_val = V_tcp_abc_l_var; | |||||
if ((ccv->flags & CCF_HYSTART_ALLOWED) && | |||||
(cubicd->flags & CUBICFLAG_HYSTART_ENABLED) && | |||||
((cubicd->flags & CUBICFLAG_HYSTART_IN_CSS) == 0)) { | |||||
/* | |||||
* Hystart is allowed and still enabled and we are not yet | |||||
* in CSS. Lets check to see if we can make a decision on | |||||
* if we need to go into CSS. | |||||
*/ | |||||
if ((cubicd->css_rttsample_count >= hystart_n_rttsamples) && | |||||
(CCV(ccv, snd_cwnd) > | |||||
(hystart_lowcwnd * tcp_fixed_maxseg(ccv->ccvc.tcp)))) { | |||||
uint32_t rtt_thresh; | |||||
/* Clamp (minrtt_thresh, lastround/8, maxrtt_thresh) */ | |||||
rtt_thresh = (cubicd->css_lastround_minrtt >> 3); | |||||
if (rtt_thresh < hystart_minrtt_thresh) | |||||
rtt_thresh = hystart_minrtt_thresh; | |||||
if (rtt_thresh > hystart_maxrtt_thresh) | |||||
rtt_thresh = hystart_maxrtt_thresh; | |||||
cubic_log_hystart_event(ccv, cubicd, 1, rtt_thresh); | |||||
if (cubicd->css_current_round_minrtt >= (cubicd->css_lastround_minrtt + rtt_thresh)) { | |||||
/* Enter CSS */ | |||||
cubicd->flags |= CUBICFLAG_HYSTART_IN_CSS; | |||||
cubicd->css_fas_at_css_entry = cubicd->css_lowrtt_fas; | |||||
cubicd->css_baseline_minrtt = cubicd->css_current_round_minrtt; | |||||
cubicd->css_entered_at_round = cubicd->css_current_round; | |||||
cubic_log_hystart_event(ccv, cubicd, 2, rtt_thresh); | |||||
} | |||||
} | |||||
} | |||||
if (CCV(ccv, snd_nxt) == CCV(ccv, snd_max)) | |||||
incr = min(ccv->bytes_this_ack, | |||||
ccv->nsegs * abc_val * | |||||
CCV(ccv, t_maxseg)); | |||||
else | |||||
incr = min(ccv->bytes_this_ack, CCV(ccv, t_maxseg)); | |||||
/* Only if Hystart is enabled will the flag get set */ | |||||
if (cubicd->flags & CUBICFLAG_HYSTART_IN_CSS) { | |||||
incr /= hystart_css_growth_div; | |||||
cubic_log_hystart_event(ccv, cubicd, 3, incr); | |||||
} | |||||
/* ABC is on by default, so incr equals 0 frequently. */ | |||||
if (incr > 0) | |||||
CCV(ccv, snd_cwnd) = min((cw + incr), | |||||
TCP_MAXWIN << CCV(ccv, snd_scale)); | |||||
} | |||||
static void | |||||
cubic_ack_received(struct cc_var *ccv, uint16_t type) | cubic_ack_received(struct cc_var *ccv, uint16_t type) | ||||
{ | { | ||||
struct cubic *cubic_data; | struct cubic *cubic_data; | ||||
unsigned long w_tf, w_cubic_next; | unsigned long w_tf, w_cubic_next; | ||||
int ticks_since_cong; | int ticks_since_cong; | ||||
cubic_data = ccv->cc_data; | cubic_data = ccv->cc_data; | ||||
cubic_record_rtt(ccv); | cubic_record_rtt(ccv); | ||||
/* | /* | ||||
* For a regular ACK and we're not in cong/fast recovery and | * For a regular ACK and we're not in cong/fast recovery and | ||||
* we're cwnd limited, always recalculate cwnd. | * we're cwnd limited, always recalculate cwnd. | ||||
*/ | */ | ||||
if (type == CC_ACK && !IN_RECOVERY(CCV(ccv, t_flags)) && | if (type == CC_ACK && !IN_RECOVERY(CCV(ccv, t_flags)) && | ||||
(ccv->flags & CCF_CWND_LIMITED)) { | (ccv->flags & CCF_CWND_LIMITED)) { | ||||
/* Use the logic in NewReno ack_received() for slow start. */ | /* Use the logic in NewReno ack_received() for slow start. */ | ||||
if (CCV(ccv, snd_cwnd) <= CCV(ccv, snd_ssthresh) || | if (CCV(ccv, snd_cwnd) <= CCV(ccv, snd_ssthresh) || | ||||
cubic_data->min_rtt_ticks == TCPTV_SRTTBASE) { | cubic_data->min_rtt_ticks == TCPTV_SRTTBASE) { | ||||
cubic_data->flags |= CUBICFLAG_IN_SLOWSTART; | cubic_does_slow_start(ccv, cubic_data); | ||||
newreno_cc_ack_received(ccv, type); | |||||
} else { | } else { | ||||
if (cubic_data->flags & CUBICFLAG_HYSTART_IN_CSS) { | |||||
/* | |||||
* We have slipped into CA with | |||||
* CSS active. Deactivate all. | |||||
*/ | |||||
/* Turn off the CSS flag */ | |||||
cubic_data->flags &= ~CUBICFLAG_HYSTART_IN_CSS; | |||||
/* Disable use of CSS in the future except long idle */ | |||||
cubic_data->flags &= ~CUBICFLAG_HYSTART_ENABLED; | |||||
cubic_log_hystart_event(ccv, cubic_data, 11, CCV(ccv, snd_ssthresh)); | |||||
} | |||||
if ((cubic_data->flags & CUBICFLAG_RTO_EVENT) && | if ((cubic_data->flags & CUBICFLAG_RTO_EVENT) && | ||||
(cubic_data->flags & CUBICFLAG_IN_SLOWSTART)) { | (cubic_data->flags & CUBICFLAG_IN_SLOWSTART)) { | ||||
/* RFC8312 Section 4.7 */ | /* RFC8312 Section 4.7 */ | ||||
cubic_data->flags &= ~(CUBICFLAG_RTO_EVENT | | cubic_data->flags &= ~(CUBICFLAG_RTO_EVENT | | ||||
CUBICFLAG_IN_SLOWSTART); | CUBICFLAG_IN_SLOWSTART); | ||||
cubic_data->max_cwnd = CCV(ccv, snd_cwnd); | cubic_data->max_cwnd = CCV(ccv, snd_cwnd); | ||||
cubic_data->K = 0; | cubic_data->K = 0; | ||||
} else if (cubic_data->flags & (CUBICFLAG_IN_SLOWSTART | | } else if (cubic_data->flags & (CUBICFLAG_IN_SLOWSTART | | ||||
▲ Show 20 Lines • Show All 75 Lines • ▼ Show 20 Lines | |||||
cubic_after_idle(struct cc_var *ccv) | cubic_after_idle(struct cc_var *ccv) | ||||
{ | { | ||||
struct cubic *cubic_data; | struct cubic *cubic_data; | ||||
cubic_data = ccv->cc_data; | cubic_data = ccv->cc_data; | ||||
cubic_data->max_cwnd = ulmax(cubic_data->max_cwnd, CCV(ccv, snd_cwnd)); | cubic_data->max_cwnd = ulmax(cubic_data->max_cwnd, CCV(ccv, snd_cwnd)); | ||||
cubic_data->K = cubic_k(cubic_data->max_cwnd / CCV(ccv, t_maxseg)); | cubic_data->K = cubic_k(cubic_data->max_cwnd / CCV(ccv, t_maxseg)); | ||||
if ((cubic_data->flags & CUBICFLAG_HYSTART_ENABLED) == 0) { | |||||
if (CCV(ccv, snd_cwnd) <= (hystart_lowcwnd * tcp_fixed_maxseg(ccv->ccvc.tcp))) { | |||||
/* | |||||
* Re-enable hystart if our cwnd has fallen below | |||||
* the hystart lowcwnd point. | |||||
*/ | |||||
cubic_data->flags &= ~CUBICFLAG_HYSTART_IN_CSS; | |||||
cubic_data->flags |= CUBICFLAG_HYSTART_ENABLED; | |||||
cubic_log_hystart_event(ccv, cubic_data, 12, CCV(ccv, snd_ssthresh)); | |||||
} | |||||
} | |||||
newreno_cc_after_idle(ccv); | newreno_cc_after_idle(ccv); | ||||
cubic_data->t_last_cong = ticks; | cubic_data->t_last_cong = ticks; | ||||
} | } | ||||
static void | static void | ||||
cubic_cb_destroy(struct cc_var *ccv) | cubic_cb_destroy(struct cc_var *ccv) | ||||
{ | { | ||||
free(ccv->cc_data, M_CC_MEM); | free(ccv->cc_data, M_CC_MEM); | ||||
Show All 19 Lines | if (ptr == NULL) { | ||||
cubic_data = ptr; | cubic_data = ptr; | ||||
/* Init some key variables with sensible defaults. */ | /* Init some key variables with sensible defaults. */ | ||||
cubic_data->t_last_cong = ticks; | cubic_data->t_last_cong = ticks; | ||||
cubic_data->min_rtt_ticks = TCPTV_SRTTBASE; | cubic_data->min_rtt_ticks = TCPTV_SRTTBASE; | ||||
cubic_data->mean_rtt_ticks = 1; | cubic_data->mean_rtt_ticks = 1; | ||||
ccv->cc_data = cubic_data; | ccv->cc_data = cubic_data; | ||||
cubic_data->flags = CUBICFLAG_HYSTART_ENABLED; | |||||
/* At init set both to infinity */ | |||||
cubic_data->css_lastround_minrtt = 0xffffffff; | |||||
cubic_data->css_current_round_minrtt = 0xffffffff; | |||||
cubic_data->css_current_round = 0; | |||||
cubic_data->css_baseline_minrtt = 0xffffffff; | |||||
cubic_data->css_rttsample_count = 0; | |||||
cubic_data->css_entered_at_round = 0; | |||||
cubic_data->css_fas_at_css_entry = 0; | |||||
cubic_data->css_lowrtt_fas = 0; | |||||
cubic_data->css_last_fas = 0; | |||||
return (0); | return (0); | ||||
} | } | ||||
/* | /* | ||||
* Perform any necessary tasks before we enter congestion recovery. | * Perform any necessary tasks before we enter congestion recovery. | ||||
*/ | */ | ||||
static void | static void | ||||
cubic_cong_signal(struct cc_var *ccv, uint32_t type) | cubic_cong_signal(struct cc_var *ccv, uint32_t type) | ||||
{ | { | ||||
struct cubic *cubic_data; | struct cubic *cubic_data; | ||||
u_int mss; | u_int mss; | ||||
cubic_data = ccv->cc_data; | cubic_data = ccv->cc_data; | ||||
mss = tcp_maxseg(ccv->ccvc.tcp); | mss = tcp_maxseg(ccv->ccvc.tcp); | ||||
switch (type) { | switch (type) { | ||||
case CC_NDUPACK: | case CC_NDUPACK: | ||||
if (cubic_data->flags & CUBICFLAG_HYSTART_ENABLED) { | |||||
/* Make sure the flags are all off we had a loss */ | |||||
cubic_data->flags &= ~CUBICFLAG_HYSTART_ENABLED; | |||||
cubic_data->flags &= ~CUBICFLAG_HYSTART_IN_CSS; | |||||
cubic_log_hystart_event(ccv, cubic_data, 10, CCV(ccv, snd_ssthresh)); | |||||
} | |||||
if (!IN_FASTRECOVERY(CCV(ccv, t_flags))) { | if (!IN_FASTRECOVERY(CCV(ccv, t_flags))) { | ||||
if (!IN_CONGRECOVERY(CCV(ccv, t_flags))) { | if (!IN_CONGRECOVERY(CCV(ccv, t_flags))) { | ||||
cubic_ssthresh_update(ccv, mss); | cubic_ssthresh_update(ccv, mss); | ||||
cubic_data->flags |= CUBICFLAG_CONG_EVENT; | cubic_data->flags |= CUBICFLAG_CONG_EVENT; | ||||
cubic_data->t_last_cong = ticks; | cubic_data->t_last_cong = ticks; | ||||
cubic_data->K = cubic_k(cubic_data->max_cwnd / mss); | cubic_data->K = cubic_k(cubic_data->max_cwnd / mss); | ||||
} | } | ||||
ENTER_RECOVERY(CCV(ccv, t_flags)); | ENTER_RECOVERY(CCV(ccv, t_flags)); | ||||
} | } | ||||
break; | break; | ||||
case CC_ECN: | case CC_ECN: | ||||
if (cubic_data->flags & CUBICFLAG_HYSTART_ENABLED) { | |||||
/* Make sure the flags are all off we had a loss */ | |||||
cubic_data->flags &= ~CUBICFLAG_HYSTART_ENABLED; | |||||
cubic_data->flags &= ~CUBICFLAG_HYSTART_IN_CSS; | |||||
cubic_log_hystart_event(ccv, cubic_data, 9, CCV(ccv, snd_ssthresh)); | |||||
} | |||||
if (!IN_CONGRECOVERY(CCV(ccv, t_flags))) { | if (!IN_CONGRECOVERY(CCV(ccv, t_flags))) { | ||||
cubic_ssthresh_update(ccv, mss); | cubic_ssthresh_update(ccv, mss); | ||||
cubic_data->flags |= CUBICFLAG_CONG_EVENT; | cubic_data->flags |= CUBICFLAG_CONG_EVENT; | ||||
cubic_data->t_last_cong = ticks; | cubic_data->t_last_cong = ticks; | ||||
cubic_data->K = cubic_k(cubic_data->max_cwnd / mss); | cubic_data->K = cubic_k(cubic_data->max_cwnd / mss); | ||||
CCV(ccv, snd_cwnd) = CCV(ccv, snd_ssthresh); | CCV(ccv, snd_cwnd) = CCV(ccv, snd_ssthresh); | ||||
ENTER_CONGRECOVERY(CCV(ccv, t_flags)); | ENTER_CONGRECOVERY(CCV(ccv, t_flags)); | ||||
} | } | ||||
▲ Show 20 Lines • Show All 166 Lines • ▼ Show 20 Lines | if ((cubic_data->flags & CUBICFLAG_CONG_EVENT) == 0) { | ||||
ssthresh = cwnd >> 1; | ssthresh = cwnd >> 1; | ||||
cubic_data->max_cwnd = ((uint64_t)cwnd * | cubic_data->max_cwnd = ((uint64_t)cwnd * | ||||
CUBIC_BETA) >> CUBIC_SHIFT; | CUBIC_BETA) >> CUBIC_SHIFT; | ||||
} else { | } else { | ||||
ssthresh = ((uint64_t)cwnd * | ssthresh = ((uint64_t)cwnd * | ||||
CUBIC_BETA) >> CUBIC_SHIFT; | CUBIC_BETA) >> CUBIC_SHIFT; | ||||
} | } | ||||
CCV(ccv, snd_ssthresh) = max(ssthresh, 2 * maxseg); | CCV(ccv, snd_ssthresh) = max(ssthresh, 2 * maxseg); | ||||
} | |||||
static void | |||||
cubic_rttsample(struct cc_var *ccv, uint32_t usec_rtt, uint32_t rxtcnt, uint32_t fas) | |||||
{ | |||||
struct cubic *cubicd; | |||||
cubicd = ccv->cc_data; | |||||
if (rxtcnt > 1) { | |||||
/* | |||||
* Only look at RTT's that are non-ambiguous. | |||||
*/ | |||||
return; | |||||
} | |||||
cubicd->css_rttsample_count++; | |||||
cubicd->css_last_fas = fas; | |||||
if (cubicd->css_current_round_minrtt > usec_rtt) { | |||||
cubicd->css_current_round_minrtt = usec_rtt; | |||||
cubicd->css_lowrtt_fas = cubicd->css_last_fas; | |||||
} | |||||
if ((cubicd->flags & CUBICFLAG_HYSTART_IN_CSS) && | |||||
(cubicd->css_rttsample_count >= hystart_n_rttsamples) && | |||||
(cubicd->css_baseline_minrtt > cubicd->css_current_round_minrtt)) { | |||||
/* | |||||
* We were in CSS and the RTT is now less, we | |||||
* entered CSS erroneously. | |||||
*/ | |||||
cubicd->flags &= ~CUBICFLAG_HYSTART_IN_CSS; | |||||
cubic_log_hystart_event(ccv, cubicd, 8, cubicd->css_baseline_minrtt); | |||||
cubicd->css_baseline_minrtt = 0xffffffff; | |||||
} | |||||
if (cubicd->flags & CUBICFLAG_HYSTART_ENABLED) | |||||
cubic_log_hystart_event(ccv, cubicd, 5, usec_rtt); | |||||
} | |||||
static void | |||||
cubic_newround(struct cc_var *ccv, uint32_t round_cnt) | |||||
{ | |||||
struct cubic *cubicd; | |||||
cubicd = ccv->cc_data; | |||||
/* We have entered a new round */ | |||||
cubicd->css_lastround_minrtt = cubicd->css_current_round_minrtt; | |||||
cubicd->css_current_round_minrtt = 0xffffffff; | |||||
cubicd->css_rttsample_count = 0; | |||||
cubicd->css_current_round = round_cnt; | |||||
if ((cubicd->flags & CUBICFLAG_HYSTART_IN_CSS) && | |||||
((round_cnt - cubicd->css_entered_at_round) >= hystart_css_rounds)) { | |||||
/* Enter CA */ | |||||
if (ccv->flags & CCF_HYSTART_CAN_SH_CWND) { | |||||
/* | |||||
* We engage more than snd_ssthresh, engage | |||||
* the brakes!! Though we will stay in SS to | |||||
* creep back up again, so lets leave CSS active | |||||
* and give us hystart_css_rounds more rounds. | |||||
*/ | |||||
if (ccv->flags & CCF_HYSTART_CONS_SSTH) { | |||||
CCV(ccv, snd_ssthresh) = ((cubicd->css_lowrtt_fas + cubicd->css_fas_at_css_entry) / 2); | |||||
} else { | |||||
CCV(ccv, snd_ssthresh) = cubicd->css_lowrtt_fas; | |||||
} | |||||
CCV(ccv, snd_cwnd) = cubicd->css_fas_at_css_entry; | |||||
cubicd->css_entered_at_round = round_cnt; | |||||
} else { | |||||
CCV(ccv, snd_ssthresh) = CCV(ccv, snd_cwnd); | |||||
/* Turn off the CSS flag */ | |||||
cubicd->flags &= ~CUBICFLAG_HYSTART_IN_CSS; | |||||
/* Disable use of CSS in the future except long idle */ | |||||
cubicd->flags &= ~CUBICFLAG_HYSTART_ENABLED; | |||||
} | |||||
cubic_log_hystart_event(ccv, cubicd, 6, CCV(ccv, snd_ssthresh)); | |||||
} | |||||
if (cubicd->flags & CUBICFLAG_HYSTART_ENABLED) | |||||
cubic_log_hystart_event(ccv, cubicd, 4, round_cnt); | |||||
} | } | ||||
DECLARE_CC_MODULE(cubic, &cubic_cc_algo); | DECLARE_CC_MODULE(cubic, &cubic_cc_algo); | ||||
MODULE_VERSION(cubic, 2); | MODULE_VERSION(cubic, 2); |
Like a mss is used in cubic_cong_signal(), and as ABC is involved, for accurate calculation, suggest to use "u_int mss = tcp_maxseg(ccv->ccvc.tcp);", and use mss instead of t_maxseg below.