Differential D40436 Diff 122904 sys/netinet/cc/cc_cubic.c

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sys/netinet/cc/cc_cubic.c

Show First 20 Lines • Show All 233 Lines • ▼ Show 20 Lines	if (incr > 0)
CCV(ccv, snd_cwnd) = min((cw + incr),		CCV(ccv, snd_cwnd) = min((cw + incr),
TCP_MAXWIN << CCV(ccv, snd_scale));		TCP_MAXWIN << CCV(ccv, snd_scale));
}		}

static void		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_est, W_cubic;
int usecs_since_cong;		int usecs_since_epoch;

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.
*/		*/
Show All 15 Lines	if (CCV(ccv, snd_cwnd) <= CCV(ccv, snd_ssthresh) \|\|
cubic_data->flags &= ~CUBICFLAG_HYSTART_ENABLED;		cubic_data->flags &= ~CUBICFLAG_HYSTART_ENABLED;
cubic_log_hystart_event(ccv, cubic_data, 11, CCV(ccv, snd_ssthresh));		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->W_max = 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 \|
CUBICFLAG_IN_APPLIMIT)) {		CUBICFLAG_IN_APPLIMIT)) {
cubic_data->flags &= ~(CUBICFLAG_IN_SLOWSTART \|		cubic_data->flags &= ~(CUBICFLAG_IN_SLOWSTART \|
CUBICFLAG_IN_APPLIMIT);		CUBICFLAG_IN_APPLIMIT);
cubic_data->t_last_cong = ticks;		cubic_data->t_epoch = ticks;
cubic_data->K = cubic_k(cubic_data->max_cwnd /		cubic_data->K = cubic_k(cubic_data->W_max /
CCV(ccv, t_maxseg));		CCV(ccv, t_maxseg));
}		}
usecs_since_cong = (ticks - cubic_data->t_last_cong) * tick;		usecs_since_epoch = (ticks - cubic_data->t_epoch) * tick;
if (usecs_since_cong < 0) {		if (usecs_since_epoch < 0) {
/*		/*
* dragging t_last_cong along		* dragging t_epoch along
*/		*/
usecs_since_cong = INT_MAX;		usecs_since_epoch = INT_MAX;
cubic_data->t_last_cong = ticks - INT_MAX;		cubic_data->t_epoch = ticks - INT_MAX;
}		}
/*		/*
* The mean RTT is used to best reflect the equations in		* The mean RTT is used to best reflect the equations in
* the I-D. Using min_rtt in the tf_cwnd calculation		* the I-D. Using min_rtt in the tf_cwnd calculation
* causes w_tf to grow much faster than it should if the		* causes W_est to grow much faster than it should if the
* RTT is dominated by network buffering rather than		* RTT is dominated by network buffering rather than
* propagation delay.		* propagation delay.
*/		*/
w_tf = tf_cwnd(usecs_since_cong, cubic_data->mean_rtt_usecs,		W_est = tf_cwnd(usecs_since_epoch, cubic_data->mean_rtt_usecs,
cubic_data->max_cwnd, CCV(ccv, t_maxseg));		cubic_data->W_max, CCV(ccv, t_maxseg));

w_cubic_next = cubic_cwnd(usecs_since_cong +		W_cubic = cubic_cwnd(usecs_since_epoch +
cubic_data->mean_rtt_usecs,		cubic_data->mean_rtt_usecs,
cubic_data->max_cwnd,		cubic_data->W_max,
CCV(ccv, t_maxseg),		CCV(ccv, t_maxseg),
cubic_data->K);		cubic_data->K);

ccv->flags &= ~CCF_ABC_SENTAWND;		ccv->flags &= ~CCF_ABC_SENTAWND;

if (w_cubic_next < w_tf) {		if (W_cubic < W_est) {
/*		/*
* TCP-friendly region, follow tf		* TCP-friendly region, follow tf
* cwnd growth.		* cwnd growth.
*/		*/
if (CCV(ccv, snd_cwnd) < w_tf)		if (CCV(ccv, snd_cwnd) < W_est)
CCV(ccv, snd_cwnd) = ulmin(w_tf, INT_MAX);		CCV(ccv, snd_cwnd) = ulmin(W_est, INT_MAX);
} else if (CCV(ccv, snd_cwnd) < w_cubic_next) {		} else if (CCV(ccv, snd_cwnd) < W_cubic) {
/*		/*
* Concave or convex region, follow CUBIC		* Concave or convex region, follow CUBIC
* cwnd growth.		* cwnd growth.
* Only update snd_cwnd, if it doesn't shrink.		* Only update snd_cwnd, if it doesn't shrink.
*/		*/
CCV(ccv, snd_cwnd) = ulmin(w_cubic_next,		CCV(ccv, snd_cwnd) = ulmin(W_cubic, INT_MAX);
INT_MAX);
}		}

/*		/*
* If we're not in slow start and we're probing for a		* If we're not in slow start and we're probing for a
* new cwnd limit at the start of a connection		* new cwnd limit at the start of a connection
* (happens when hostcache has a relevant entry),		* (happens when hostcache has a relevant entry),
* keep updating our current estimate of the		* keep updating our current estimate of the
* max_cwnd.		* W_max.
*/		*/
if (((cubic_data->flags & CUBICFLAG_CONG_EVENT) == 0) &&		if (((cubic_data->flags & CUBICFLAG_CONG_EVENT) == 0) &&
cubic_data->max_cwnd < CCV(ccv, snd_cwnd)) {		cubic_data->W_max < CCV(ccv, snd_cwnd)) {
cubic_data->max_cwnd = CCV(ccv, snd_cwnd);		cubic_data->W_max = CCV(ccv, snd_cwnd);
cubic_data->K = cubic_k(cubic_data->max_cwnd /		cubic_data->K = cubic_k(cubic_data->W_max /
CCV(ccv, t_maxseg));		CCV(ccv, t_maxseg));
}		}
}		}
} else if (type == CC_ACK && !IN_RECOVERY(CCV(ccv, t_flags)) &&		} else if (type == CC_ACK && !IN_RECOVERY(CCV(ccv, t_flags)) &&
!(ccv->flags & CCF_CWND_LIMITED)) {		!(ccv->flags & CCF_CWND_LIMITED)) {
cubic_data->flags \|= CUBICFLAG_IN_APPLIMIT;		cubic_data->flags \|= CUBICFLAG_IN_APPLIMIT;
}		}
}		}

/*		/*
* This is a CUBIC specific implementation of after_idle.		* This is a CUBIC specific implementation of after_idle.
* - Reset cwnd by calling New Reno implementation of after_idle.		* - Reset cwnd by calling New Reno implementation of after_idle.
* - Reset t_last_cong.		* - Reset t_epoch.
*/		*/
static void		static void
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->W_max = ulmax(cubic_data->W_max, CCV(ccv, snd_cwnd));
cubic_data->K = cubic_k(cubic_data->max_cwnd / CCV(ccv, t_maxseg));		cubic_data->K = cubic_k(cubic_data->W_max / CCV(ccv, t_maxseg));
if ((cubic_data->flags & CUBICFLAG_HYSTART_ENABLED) == 0) {		if ((cubic_data->flags & CUBICFLAG_HYSTART_ENABLED) == 0) {
/*		/*
* Re-enable hystart if we have been idle.		* Re-enable hystart if we have been idle.
*/		*/
cubic_data->flags &= ~CUBICFLAG_HYSTART_IN_CSS;		cubic_data->flags &= ~CUBICFLAG_HYSTART_IN_CSS;
cubic_data->flags \|= CUBICFLAG_HYSTART_ENABLED;		cubic_data->flags \|= CUBICFLAG_HYSTART_ENABLED;
cubic_log_hystart_event(ccv, cubic_data, 12, CCV(ccv, snd_ssthresh));		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_epoch = 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 12 Lines	cubic_cb_init(struct cc_var ccv, void ptr)
if (ptr == NULL) {		if (ptr == NULL) {
cubic_data = malloc(sizeof(struct cubic), M_CC_MEM, M_NOWAIT\|M_ZERO);		cubic_data = malloc(sizeof(struct cubic), M_CC_MEM, M_NOWAIT\|M_ZERO);
if (cubic_data == NULL)		if (cubic_data == NULL)
return (ENOMEM);		return (ENOMEM);
} else		} else
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_epoch = ticks;
cubic_data->min_rtt_usecs = TCPTV_SRTTBASE;		cubic_data->min_rtt_usecs = TCPTV_SRTTBASE;
cubic_data->mean_rtt_usecs = 1;		cubic_data->mean_rtt_usecs = 1;

ccv->cc_data = cubic_data;		ccv->cc_data = cubic_data;
cubic_data->flags = CUBICFLAG_HYSTART_ENABLED;		cubic_data->flags = CUBICFLAG_HYSTART_ENABLED;
/* At init set both to infinity */		/* At init set both to infinity */
cubic_data->css_lastround_minrtt = 0xffffffff;		cubic_data->css_lastround_minrtt = 0xffffffff;
cubic_data->css_current_round_minrtt = 0xffffffff;		cubic_data->css_current_round_minrtt = 0xffffffff;
Show All 27 Lines	if (cubic_data->flags & CUBICFLAG_HYSTART_ENABLED) {
cubic_data->flags &= ~CUBICFLAG_HYSTART_ENABLED;		cubic_data->flags &= ~CUBICFLAG_HYSTART_ENABLED;
cubic_data->flags &= ~CUBICFLAG_HYSTART_IN_CSS;		cubic_data->flags &= ~CUBICFLAG_HYSTART_IN_CSS;
cubic_log_hystart_event(ccv, cubic_data, 10, CCV(ccv, snd_ssthresh));		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_epoch = ticks;
cubic_data->K = cubic_k(cubic_data->max_cwnd / mss);		cubic_data->K = cubic_k(cubic_data->W_max / 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) {		if (cubic_data->flags & CUBICFLAG_HYSTART_ENABLED) {
/* Make sure the flags are all off we had a loss */		/* Make sure the flags are all off we had a loss */
cubic_data->flags &= ~CUBICFLAG_HYSTART_ENABLED;		cubic_data->flags &= ~CUBICFLAG_HYSTART_ENABLED;
cubic_data->flags &= ~CUBICFLAG_HYSTART_IN_CSS;		cubic_data->flags &= ~CUBICFLAG_HYSTART_IN_CSS;
cubic_log_hystart_event(ccv, cubic_data, 9, CCV(ccv, snd_ssthresh));		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_epoch = ticks;
cubic_data->K = cubic_k(cubic_data->max_cwnd / mss);		cubic_data->K = cubic_k(cubic_data->W_max / 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));
}		}
break;		break;

case CC_RTO:		case CC_RTO:
/* RFC8312 Section 4.7 */		/* RFC8312 Section 4.7 */
if (CCV(ccv, t_rxtshift) == 1) {		if (CCV(ccv, t_rxtshift) == 1) {
cubic_data->t_last_cong_prev = cubic_data->t_last_cong;		/*
cubic_data->prev_max_cwnd_cp = cubic_data->prev_max_cwnd;		* Remember the state only for the first RTO event. This
		* will help us restore the state to the values seen
		* at the most recent congestion avoidance stage before
		* the current RTO event.
		*/
		cubic_data->undo_t_epoch = cubic_data->t_epoch;
		cubic_data->undo_cwnd_epoch = cubic_data->cwnd_epoch;
		cubic_data->undo_W_est = cubic_data->W_est;
		cubic_data->undo_cwnd_prior = cubic_data->cwnd_prior;
		cubic_data->undo_W_max = cubic_data->W_max;
		cubic_data->undo_K = cubic_data->K;
}		}
cubic_data->flags \|= CUBICFLAG_CONG_EVENT \| CUBICFLAG_RTO_EVENT;		cubic_data->flags \|= CUBICFLAG_CONG_EVENT \| CUBICFLAG_RTO_EVENT;
cubic_data->prev_max_cwnd = cubic_data->max_cwnd;		cubic_data->undo_W_max = cubic_data->W_max;
		cubic_data->num_cong_events++;
CCV(ccv, snd_ssthresh) = ((uint64_t)CCV(ccv, snd_cwnd) *		CCV(ccv, snd_ssthresh) = ((uint64_t)CCV(ccv, snd_cwnd) *
CUBIC_BETA) >> CUBIC_SHIFT;		CUBIC_BETA) >> CUBIC_SHIFT;
CCV(ccv, snd_cwnd) = mss;		CCV(ccv, snd_cwnd) = mss;
break;		break;

case CC_RTO_ERR:		case CC_RTO_ERR:
cubic_data->flags &= ~(CUBICFLAG_CONG_EVENT \| CUBICFLAG_RTO_EVENT);		cubic_data->flags &= ~(CUBICFLAG_CONG_EVENT \| CUBICFLAG_RTO_EVENT);
cubic_data->max_cwnd = cubic_data->prev_max_cwnd;		cubic_data->num_cong_events--;
cubic_data->prev_max_cwnd = cubic_data->prev_max_cwnd_cp;		cubic_data->K = cubic_data->undo_K;
cubic_data->t_last_cong = cubic_data->t_last_cong_prev;		cubic_data->cwnd_prior = cubic_data->undo_cwnd_prior;
cubic_data->K = cubic_k(cubic_data->max_cwnd / mss);		cubic_data->W_max = cubic_data->undo_W_max;
		cubic_data->W_est = cubic_data->undo_W_est;
		cubic_data->cwnd_epoch = cubic_data->undo_cwnd_epoch;
		cubic_data->t_epoch = cubic_data->undo_t_epoch;
break;		break;
}		}
}		}

static void		static void
cubic_conn_init(struct cc_var *ccv)		cubic_conn_init(struct cc_var *ccv)
{		{
struct cubic *cubic_data;		struct cubic *cubic_data;

cubic_data = ccv->cc_data;		cubic_data = ccv->cc_data;

/*		/*
* Ensure we have a sane initial value for max_cwnd recorded. Without		* Ensure we have a sane initial value for W_max recorded. Without
* this here bad things happen when entries from the TCP hostcache		* this here bad things happen when entries from the TCP hostcache
* get used.		* get used.
*/		*/
cubic_data->max_cwnd = CCV(ccv, snd_cwnd);		cubic_data->W_max = CCV(ccv, snd_cwnd);
}		}

static int		static int
cubic_mod_init(void)		cubic_mod_init(void)
{		{
return (0);		return (0);
}		}

Show All 25 Lines	if (IN_FASTRECOVERY(CCV(ccv, t_flags))) {
if (pipe < CCV(ccv, snd_ssthresh))		if (pipe < CCV(ccv, snd_ssthresh))
/*		/*
* Ensure that cwnd does not collapse to 1 MSS under		* Ensure that cwnd does not collapse to 1 MSS under
* adverse conditions. Implements RFC6582		* adverse conditions. Implements RFC6582
*/		*/
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 W_max. */
CCV(ccv, snd_cwnd) = max(((uint64_t)cubic_data->max_cwnd *		CCV(ccv, snd_cwnd) = max(((uint64_t)cubic_data->W_max *
CUBIC_BETA) >> CUBIC_SHIFT,		CUBIC_BETA) >> CUBIC_SHIFT,
2 * CCV(ccv, t_maxseg));		2 * CCV(ccv, t_maxseg));
}		}

/* 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_usecs >= cubic_data->epoch_ack_count) {		cubic_data->sum_rtt_usecs >= cubic_data->epoch_ack_count) {
cubic_data->mean_rtt_usecs = (int)(cubic_data->sum_rtt_usecs /		cubic_data->mean_rtt_usecs = (int)(cubic_data->sum_rtt_usecs /
▲ Show 20 Lines • Show All 59 Lines • ▼ Show 20 Lines	cubic_ssthresh_update(struct cc_var *ccv, uint32_t maxseg)
struct cubic *cubic_data;		struct cubic *cubic_data;
uint32_t ssthresh;		uint32_t ssthresh;
uint32_t cwnd;		uint32_t cwnd;

cubic_data = ccv->cc_data;		cubic_data = ccv->cc_data;
cwnd = CCV(ccv, snd_cwnd);		cwnd = CCV(ccv, snd_cwnd);

/* Fast convergence heuristic. */		/* Fast convergence heuristic. */
if (cwnd < cubic_data->max_cwnd) {		if (cwnd < cubic_data->W_max) {
cwnd = ((uint64_t)cwnd * CUBIC_FC_FACTOR) >> CUBIC_SHIFT;		cwnd = ((uint64_t)cwnd * CUBIC_FC_FACTOR) >> CUBIC_SHIFT;
}		}
cubic_data->prev_max_cwnd = cubic_data->max_cwnd;		cubic_data->undo_W_max = cubic_data->W_max;
cubic_data->max_cwnd = cwnd;		cubic_data->W_max = cwnd;

/*		/*
* On the first congestion event, set ssthresh to cwnd * 0.5		* On the first congestion event, set ssthresh to cwnd * 0.5
* and reduce max_cwnd to cwnd * beta. This aligns the cubic concave		* and reduce W_max to cwnd * beta. This aligns the cubic concave
* region appropriately. On subsequent congestion events, set		* region appropriately. On subsequent congestion events, set
* ssthresh to cwnd * beta.		* ssthresh to cwnd * beta.
*/		*/
if ((cubic_data->flags & CUBICFLAG_CONG_EVENT) == 0) {		if ((cubic_data->flags & CUBICFLAG_CONG_EVENT) == 0) {
ssthresh = cwnd >> 1;		ssthresh = cwnd >> 1;
cubic_data->max_cwnd = ((uint64_t)cwnd *		cubic_data->W_max = ((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);
}		}

▲ Show 20 Lines • Show All 77 Lines • Show Last 20 Lines