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Differential D25976 Diff 75504 sys/netinet/cc/cc_cubic.c

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sys/netinet/cc/cc_cubic.c

Show First 20 Lines • Show All 278 Lines • ▼ Show 20 Linescubic_cong_signal(struct cc_var *ccv, uint32_t type)
cubic_data = ccv->cc_data; cubic_data = ccv->cc_data;
switch (type) { switch (type) {
case CC_NDUPACK: case CC_NDUPACK:
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); cubic_ssthresh_update(ccv);
cubic_data->flags |= CUBICFLAG_CONG_EVENT; cubic_data->flags |= CUBICFLAG_CONG_EVENT;
cubic_data->prev_max_cwnd = cubic_data->max_cwnd; cubic_data->t_last_cong = ticks;
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));
} }
ENTER_RECOVERY(CCV(ccv, t_flags)); ENTER_RECOVERY(CCV(ccv, t_flags));
} }
break; break;
case CC_ECN: case CC_ECN:
if (!IN_CONGRECOVERY(CCV(ccv, t_flags))) { if (!IN_CONGRECOVERY(CCV(ccv, t_flags))) {
cubic_ssthresh_update(ccv); cubic_ssthresh_update(ccv);
cubic_data->flags |= CUBICFLAG_CONG_EVENT; cubic_data->flags |= CUBICFLAG_CONG_EVENT;
cubic_data->prev_max_cwnd = cubic_data->max_cwnd;
cubic_data->max_cwnd = CCV(ccv, snd_cwnd);
cubic_data->t_last_cong = ticks; cubic_data->t_last_cong = ticks;
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));
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));
} }
break; break;
case CC_RTO: case CC_RTO:
▲ Show 20 Lines • Show All 45 Lines • ▼ Show 20 Lines
cubic_post_recovery(struct cc_var *ccv) cubic_post_recovery(struct cc_var *ccv)
{ {
struct cubic *cubic_data; struct cubic *cubic_data;
int pipe; int pipe;
cubic_data = ccv->cc_data; cubic_data = ccv->cc_data;
pipe = 0; pipe = 0;
/* Fast convergence heuristic. */
if (cubic_data->max_cwnd < cubic_data->prev_max_cwnd)
cubic_data->max_cwnd = (cubic_data->max_cwnd * CUBIC_FC_FACTOR)
>> CUBIC_SHIFT;
if (IN_FASTRECOVERY(CCV(ccv, t_flags))) { if (IN_FASTRECOVERY(CCV(ccv, t_flags))) {
/* /*
* If inflight data is less than ssthresh, set cwnd * If inflight data is less than ssthresh, set cwnd
* conservatively to avoid a burst of data, as suggested in * conservatively to avoid a burst of data, as suggested in
* the NewReno RFC. Otherwise, use the CUBIC method. * the NewReno RFC. Otherwise, use the CUBIC method.
* *
* XXXLAS: Find a way to do this without needing curack * XXXLAS: Find a way to do this without needing curack
*/ */
Show All 10 Lines if (pipe < CCV(ccv, snd_ssthresh))
CCV(ccv, snd_cwnd) = max(pipe, CCV(ccv, t_maxseg)) + CCV(ccv, snd_cwnd) = max(pipe, CCV(ccv, t_maxseg)) +
CCV(ccv, t_maxseg); CCV(ccv, t_maxseg);
else else
/* Update cwnd based on beta and adjusted max_cwnd. */ /* Update cwnd based on beta and adjusted max_cwnd. */
CCV(ccv, snd_cwnd) = max(((uint64_t)cubic_data->max_cwnd * CCV(ccv, snd_cwnd) = max(((uint64_t)cubic_data->max_cwnd *
CUBIC_BETA) >> CUBIC_SHIFT, CUBIC_BETA) >> CUBIC_SHIFT,
2 * CCV(ccv, t_maxseg)); 2 * CCV(ccv, t_maxseg));
} }
cubic_data->t_last_cong = ticks;
/* Calculate the average RTT between congestion epochs. */ /* Calculate the average RTT between congestion epochs. */
if (cubic_data->epoch_ack_count > 0 && if (cubic_data->epoch_ack_count > 0 &&
cubic_data->sum_rtt_ticks >= cubic_data->epoch_ack_count) { cubic_data->sum_rtt_ticks >= cubic_data->epoch_ack_count) {
cubic_data->mean_rtt_ticks = (int)(cubic_data->sum_rtt_ticks / cubic_data->mean_rtt_ticks = (int)(cubic_data->sum_rtt_ticks /
cubic_data->epoch_ack_count); cubic_data->epoch_ack_count);
} }
cubic_data->epoch_ack_count = 0; cubic_data->epoch_ack_count = 0;
cubic_data->sum_rtt_ticks = 0; cubic_data->sum_rtt_ticks = 0;
cubic_data->K = cubic_k(cubic_data->max_cwnd / CCV(ccv, t_maxseg));
} }
/* /*
* Record the min RTT and sum samples for the epoch average RTT calculation. * Record the min RTT and sum samples for the epoch average RTT calculation.
*/ */
static void static void
cubic_record_rtt(struct cc_var *ccv) cubic_record_rtt(struct cc_var *ccv)
{ {
Show All 37 Lines
/* /*
* Update the ssthresh in the event of congestion. * Update the ssthresh in the event of congestion.
*/ */
static void static void
cubic_ssthresh_update(struct cc_var *ccv) cubic_ssthresh_update(struct cc_var *ccv)
{ {
struct cubic *cubic_data; struct cubic *cubic_data;
uint32_t ssthresh; uint32_t ssthresh;
uint32_t cwnd;
cubic_data = ccv->cc_data; cubic_data = ccv->cc_data;
cwnd = CCV(ccv, snd_cwnd);
/* Fast convergence heuristic. */
if (cwnd < cubic_data->max_cwnd) {
cwnd = ((uint64_t)cwnd * CUBIC_FC_FACTOR) >> CUBIC_SHIFT;
}
cubic_data->prev_max_cwnd = cubic_data->max_cwnd;
cubic_data->max_cwnd = cwnd;
/* /*
* On the first congestion event, set ssthresh to cwnd * 0.5, on * On the first congestion event, set ssthresh to cwnd * 0.5
* subsequent congestion events, set it to cwnd * beta. * and reduce max_cwnd to cwnd * beta. This aligns the cubic concave
* region appropriately. On subsequent congestion events, set
* ssthresh to cwnd * beta.
*/ */
if ((cubic_data->flags & CUBICFLAG_CONG_EVENT) == 0) if ((cubic_data->flags & CUBICFLAG_CONG_EVENT) == 0) {
ssthresh = CCV(ccv, snd_cwnd) >> 1; ssthresh = cwnd >> 1;
else cubic_data->max_cwnd = ((uint64_t)cwnd *
ssthresh = ((uint64_t)CCV(ccv, snd_cwnd) *
CUBIC_BETA) >> CUBIC_SHIFT; CUBIC_BETA) >> CUBIC_SHIFT;
} else {
ssthresh = ((uint64_t)cwnd *
CUBIC_BETA) >> CUBIC_SHIFT;
}
CCV(ccv, snd_ssthresh) = max(ssthresh, 2 * CCV(ccv, t_maxseg)); CCV(ccv, snd_ssthresh) = max(ssthresh, 2 * CCV(ccv, t_maxseg));
} }
DECLARE_CC_MODULE(cubic, &cubic_cc_algo); DECLARE_CC_MODULE(cubic, &cubic_cc_algo);
MODULE_VERSION(cubic, 1); MODULE_VERSION(cubic, 1);