Differential D32693 Diff 97817 sys/netinet/cc/cc_newreno.c

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sys/netinet/cc/cc_newreno.c

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#include <netinet/tcp_seq.h>		#include <netinet/tcp_seq.h>
#include <netinet/tcp_var.h>		#include <netinet/tcp_var.h>
#include <netinet/tcp_log_buf.h>		#include <netinet/tcp_log_buf.h>
#include <netinet/tcp_hpts.h>		#include <netinet/tcp_hpts.h>
#include <netinet/cc/cc.h>		#include <netinet/cc/cc.h>
#include <netinet/cc/cc_module.h>		#include <netinet/cc/cc_module.h>
#include <netinet/cc/cc_newreno.h>		#include <netinet/cc/cc_newreno.h>

static MALLOC_DEFINE(M_NEWRENO, "newreno data",
"newreno beta values");

static void newreno_cb_destroy(struct cc_var *ccv);		static void newreno_cb_destroy(struct cc_var *ccv);
static void newreno_ack_received(struct cc_var *ccv, uint16_t type);		static void newreno_ack_received(struct cc_var *ccv, uint16_t type);
static void newreno_after_idle(struct cc_var *ccv);		static void newreno_after_idle(struct cc_var *ccv);
static void newreno_cong_signal(struct cc_var *ccv, uint32_t type);		static void newreno_cong_signal(struct cc_var *ccv, uint32_t type);
static void newreno_post_recovery(struct cc_var *ccv);
static int newreno_ctl_output(struct cc_var ccv, struct sockopt sopt, void *buf);		static int newreno_ctl_output(struct cc_var ccv, struct sockopt sopt, void *buf);
static void newreno_newround(struct cc_var *ccv, uint32_t round_cnt);		static void newreno_newround(struct cc_var *ccv, uint32_t round_cnt);
static void newreno_rttsample(struct cc_var *ccv, uint32_t usec_rtt, uint32_t rxtcnt, uint32_t fas);		static void newreno_rttsample(struct cc_var *ccv, uint32_t usec_rtt, uint32_t rxtcnt, uint32_t fas);
static int newreno_cb_init(struct cc_var *ccv);		static int newreno_cb_init(struct cc_var ccv, void );
		static size_t newreno_data_sz(void);

VNET_DEFINE(uint32_t, newreno_beta) = 50;		VNET_DEFINE(uint32_t, newreno_beta) = 50;
VNET_DEFINE(uint32_t, newreno_beta_ecn) = 80;		VNET_DEFINE(uint32_t, newreno_beta_ecn) = 80;
#define V_newreno_beta VNET(newreno_beta)		#define V_newreno_beta VNET(newreno_beta)
#define V_newreno_beta_ecn VNET(newreno_beta_ecn)		#define V_newreno_beta_ecn VNET(newreno_beta_ecn)

struct cc_algo newreno_cc_algo = {		struct cc_algo newreno_cc_algo = {
.name = "newreno",		.name = "newreno",
.cb_destroy = newreno_cb_destroy,		.cb_destroy = newreno_cb_destroy,
.ack_received = newreno_ack_received,		.ack_received = newreno_ack_received,
.after_idle = newreno_after_idle,		.after_idle = newreno_after_idle,
.cong_signal = newreno_cong_signal,		.cong_signal = newreno_cong_signal,
.post_recovery = newreno_post_recovery,		.post_recovery = common_cc_post_recovery,
.ctl_output = newreno_ctl_output,		.ctl_output = newreno_ctl_output,
.newround = newreno_newround,		.newround = newreno_newround,
.rttsample = newreno_rttsample,		.rttsample = newreno_rttsample,
.cb_init = newreno_cb_init,		.cb_init = newreno_cb_init,
		.cc_data_sz = newreno_data_sz,
};		};

static uint32_t hystart_lowcwnd = 16;		static uint32_t hystart_lowcwnd = 16;
static uint32_t hystart_minrtt_thresh = 4000;		static uint32_t hystart_minrtt_thresh = 4000;
static uint32_t hystart_maxrtt_thresh = 16000;		static uint32_t hystart_maxrtt_thresh = 16000;
static uint32_t hystart_n_rttsamples = 8;		static uint32_t hystart_n_rttsamples = 8;
static uint32_t hystart_css_growth_div = 4;		static uint32_t hystart_css_growth_div = 4;
static uint32_t hystart_css_rounds = 5;		static uint32_t hystart_css_rounds = 5;
Show All 40 Lines	if (tp->t_logstate != TCP_LOG_STATE_OFF) {
TCP_LOG_EVENTP(tp, NULL,		TCP_LOG_EVENTP(tp, NULL,
&tp->t_inpcb->inp_socket->so_rcv,		&tp->t_inpcb->inp_socket->so_rcv,
&tp->t_inpcb->inp_socket->so_snd,		&tp->t_inpcb->inp_socket->so_snd,
TCP_HYSTART, 0,		TCP_HYSTART, 0,
0, &log, false, &tv);		0, &log, false, &tv);
}		}
}		}

		static size_t
		newreno_data_sz(void)
		{
		return (sizeof(struct newreno));
		}

static int		static int
newreno_cb_init(struct cc_var *ccv)		newreno_cb_init(struct cc_var ccv, void ptr)
{		{
struct newreno *nreno;		struct newreno *nreno;

ccv->cc_data = malloc(sizeof(struct newreno), M_NEWRENO, M_NOWAIT);		if (ptr == NULL) {
		ccv->cc_data = malloc(sizeof(struct newreno), M_CC_MEM, M_NOWAIT);
if (ccv->cc_data == NULL)		if (ccv->cc_data == NULL)
return (ENOMEM);		return (ENOMEM);
		} else
		ccv->cc_data = ptr;
nreno = (struct newreno *)ccv->cc_data;		nreno = (struct newreno *)ccv->cc_data;
/* NB: nreno is not zeroed, so initialise all fields. */		/* NB: nreno is not zeroed, so initialise all fields. */
nreno->beta = V_newreno_beta;		nreno->beta = V_newreno_beta;
nreno->beta_ecn = V_newreno_beta_ecn;		nreno->beta_ecn = V_newreno_beta_ecn;
/*		/*
* We set the enabled flag so that if		* We set the enabled flag so that if
* the socket option gets strobed and		* the socket option gets strobed and
* we have not hit a loss		* we have not hit a loss
Show All 10 Lines	newreno_cb_init(struct cc_var ccv, void ptr)
nreno->css_lowrtt_fas = 0;		nreno->css_lowrtt_fas = 0;
nreno->css_last_fas = 0;		nreno->css_last_fas = 0;
return (0);		return (0);
}		}

static void		static void
newreno_cb_destroy(struct cc_var *ccv)		newreno_cb_destroy(struct cc_var *ccv)
{		{
free(ccv->cc_data, M_NEWRENO);		free(ccv->cc_data, M_CC_MEM);
}		}

static void		static void
newreno_ack_received(struct cc_var *ccv, uint16_t type)		newreno_ack_received(struct cc_var *ccv, uint16_t type)
{		{
struct newreno *nreno;		struct newreno *nreno;

/*		nreno = ccv->cc_data;
* Other TCP congestion controls use newreno_ack_received(), but
* with their own private cc_data. Make sure the cc_data is used
* correctly.
*/
nreno = (CC_ALGO(ccv->ccvc.tcp) == &newreno_cc_algo) ? ccv->cc_data : NULL;

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)) {
u_int cw = CCV(ccv, snd_cwnd);		u_int cw = CCV(ccv, snd_cwnd);
u_int incr = CCV(ccv, t_maxseg);		u_int incr = CCV(ccv, t_maxseg);

/*		/*
* Regular in-order ACK, open the congestion window.		* Regular in-order ACK, open the congestion window.
* Method depends on which congestion control state we're		* Method depends on which congestion control state we're
Show All 17 Lines	if (type == CC_ACK && !IN_RECOVERY(CCV(ccv, t_flags)) &&
*		*
* cong avoid without ABC (RFC 5681):		* cong avoid without ABC (RFC 5681):
* Grow cwnd linearly by approximately maxseg per RTT using		* Grow cwnd linearly by approximately maxseg per RTT using
* maxseg^2 / cwnd per ACK as the increment.		* maxseg^2 / cwnd per ACK as the increment.
* If cwnd > maxseg^2, fix the cwnd increment at 1 byte to		* If cwnd > maxseg^2, fix the cwnd increment at 1 byte to
* avoid capping cwnd.		* avoid capping cwnd.
*/		*/
if (cw > CCV(ccv, snd_ssthresh)) {		if (cw > CCV(ccv, snd_ssthresh)) {
if ((nreno != NULL) &&		if (nreno->newreno_flags & CC_NEWRENO_HYSTART_IN_CSS) {
(nreno->newreno_flags & CC_NEWRENO_HYSTART_IN_CSS)) {
/*		/*
* We have slipped into CA with		* We have slipped into CA with
* CSS active. Deactivate all.		* CSS active. Deactivate all.
*/		*/
/* Turn off the CSS flag */		/* Turn off the CSS flag */
nreno->newreno_flags &= ~CC_NEWRENO_HYSTART_IN_CSS;		nreno->newreno_flags &= ~CC_NEWRENO_HYSTART_IN_CSS;
/* Disable use of CSS in the future except long idle */		/* Disable use of CSS in the future except long idle */
nreno->newreno_flags &= ~CC_NEWRENO_HYSTART_ENABLED;		nreno->newreno_flags &= ~CC_NEWRENO_HYSTART_ENABLED;
Show All 17 Lines	if (cw > CCV(ccv, snd_ssthresh)) {
* doesn't rely on tcpcb vars.		* doesn't rely on tcpcb vars.
*/		*/
uint16_t abc_val;		uint16_t abc_val;

if (ccv->flags & CCF_USE_LOCAL_ABC)		if (ccv->flags & CCF_USE_LOCAL_ABC)
abc_val = ccv->labc;		abc_val = ccv->labc;
else		else
abc_val = V_tcp_abc_l_var;		abc_val = V_tcp_abc_l_var;
if ((nreno != NULL) &&		if ((nreno->newreno_flags & CC_NEWRENO_HYSTART_ALLOWED) &&
(nreno->newreno_flags & CC_NEWRENO_HYSTART_ALLOWED) &&
(nreno->newreno_flags & CC_NEWRENO_HYSTART_ENABLED) &&		(nreno->newreno_flags & CC_NEWRENO_HYSTART_ENABLED) &&
((nreno->newreno_flags & CC_NEWRENO_HYSTART_IN_CSS) == 0)) {		((nreno->newreno_flags & CC_NEWRENO_HYSTART_IN_CSS) == 0)) {
/*		/*
* Hystart is allowed and still enabled and we are not yet		* Hystart is allowed and still enabled and we are not yet
* in CSS. Lets check to see if we can make a decision on		* in CSS. Lets check to see if we can make a decision on
* if we need to go into CSS.		* if we need to go into CSS.
*/		*/
if ((nreno->css_rttsample_count >= hystart_n_rttsamples) &&		if ((nreno->css_rttsample_count >= hystart_n_rttsamples) &&
Show All 21 Lines	if (cw > CCV(ccv, snd_ssthresh)) {
if (CCV(ccv, snd_nxt) == CCV(ccv, snd_max))		if (CCV(ccv, snd_nxt) == CCV(ccv, snd_max))
incr = min(ccv->bytes_this_ack,		incr = min(ccv->bytes_this_ack,
ccv->nsegs * abc_val *		ccv->nsegs * abc_val *
CCV(ccv, t_maxseg));		CCV(ccv, t_maxseg));
else		else
incr = min(ccv->bytes_this_ack, CCV(ccv, t_maxseg));		incr = min(ccv->bytes_this_ack, CCV(ccv, t_maxseg));

/* Only if Hystart is enabled will the flag get set */		/* Only if Hystart is enabled will the flag get set */
if ((nreno != NULL) &&		if (nreno->newreno_flags & CC_NEWRENO_HYSTART_IN_CSS) {
(nreno->newreno_flags & CC_NEWRENO_HYSTART_IN_CSS)) {
incr /= hystart_css_growth_div;		incr /= hystart_css_growth_div;
newreno_log_hystart_event(ccv, nreno, 3, incr);		newreno_log_hystart_event(ccv, nreno, 3, incr);
}		}
}		}
/* ABC is on by default, so incr equals 0 frequently. */		/* ABC is on by default, so incr equals 0 frequently. */
if (incr > 0)		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
newreno_after_idle(struct cc_var *ccv)		newreno_after_idle(struct cc_var *ccv)
{		{
struct newreno *nreno;		struct newreno *nreno;
uint32_t rw;

/*		nreno = ccv->cc_data;
* Other TCP congestion controls use newreno_after_idle(), but		common_cc_after_idle(ccv);
* with their own private cc_data. Make sure the cc_data is used		if ((nreno->newreno_flags & CC_NEWRENO_HYSTART_ENABLED) == 0) {
* correctly.
*/
nreno = (CC_ALGO(ccv->ccvc.tcp) == &newreno_cc_algo) ? ccv->cc_data : NULL;
/*
* If we've been idle for more than one retransmit timeout the old
* congestion window is no longer current and we have to reduce it to
* the restart window before we can transmit again.
*
* The restart window is the initial window or the last CWND, whichever
* is smaller.
*
* This is done to prevent us from flooding the path with a full CWND at
* wirespeed, overloading router and switch buffers along the way.
*
* See RFC5681 Section 4.1. "Restarting Idle Connections".
*
* In addition, per RFC2861 Section 2, the ssthresh is set to the
* maximum of the former ssthresh or 3/4 of the old cwnd, to
* not exit slow-start prematurely.
*/
rw = tcp_compute_initwnd(tcp_maxseg(ccv->ccvc.tcp));

CCV(ccv, snd_ssthresh) = max(CCV(ccv, snd_ssthresh),
CCV(ccv, snd_cwnd)-(CCV(ccv, snd_cwnd)>>2));

CCV(ccv, snd_cwnd) = min(rw, CCV(ccv, snd_cwnd));
if ((nreno != NULL) &&
(nreno->newreno_flags & CC_NEWRENO_HYSTART_ENABLED) == 0) {
if (CCV(ccv, snd_cwnd) <= (hystart_lowcwnd * tcp_fixed_maxseg(ccv->ccvc.tcp))) {		if (CCV(ccv, snd_cwnd) <= (hystart_lowcwnd * tcp_fixed_maxseg(ccv->ccvc.tcp))) {
/*		/*
* Re-enable hystart if our cwnd has fallen below		* Re-enable hystart if our cwnd has fallen below
* the hystart lowcwnd point.		* the hystart lowcwnd point.
*/		*/
nreno->newreno_flags &= ~CC_NEWRENO_HYSTART_IN_CSS;		nreno->newreno_flags &= ~CC_NEWRENO_HYSTART_IN_CSS;
nreno->newreno_flags \|= CC_NEWRENO_HYSTART_ENABLED;		nreno->newreno_flags \|= CC_NEWRENO_HYSTART_ENABLED;
}		}
}		}
}		}

/*		/*
* Perform any necessary tasks before we enter congestion recovery.		* Perform any necessary tasks before we enter congestion recovery.
*/		*/
static void		static void
newreno_cong_signal(struct cc_var *ccv, uint32_t type)		newreno_cong_signal(struct cc_var *ccv, uint32_t type)
{		{
struct newreno *nreno;		struct newreno *nreno;
uint32_t beta, beta_ecn, cwin, factor;		uint32_t beta, beta_ecn, cwin, factor;
u_int mss;		u_int mss;

cwin = CCV(ccv, snd_cwnd);		cwin = CCV(ccv, snd_cwnd);
mss = tcp_fixed_maxseg(ccv->ccvc.tcp);		mss = tcp_fixed_maxseg(ccv->ccvc.tcp);
/*		nreno = ccv->cc_data;
* Other TCP congestion controls use newreno_cong_signal(), but
* with their own private cc_data. Make sure the cc_data is used
* correctly.
*/
nreno = (CC_ALGO(ccv->ccvc.tcp) == &newreno_cc_algo) ? ccv->cc_data : NULL;
beta = (nreno == NULL) ? V_newreno_beta : nreno->beta;;		beta = (nreno == NULL) ? V_newreno_beta : nreno->beta;;
beta_ecn = (nreno == NULL) ? V_newreno_beta_ecn : nreno->beta_ecn;		beta_ecn = (nreno == NULL) ? V_newreno_beta_ecn : nreno->beta_ecn;
/*		/*
* Note that we only change the backoff for ECN if the		* Note that we only change the backoff for ECN if the
* global sysctl V_cc_do_abe is set <or> the stack itself		* global sysctl V_cc_do_abe is set <or> the stack itself
* has set a flag in our newreno_flags (due to pacing) telling		* has set a flag in our newreno_flags (due to pacing) telling
* us to use the lower valued back-off.		* us to use the lower valued back-off.
*/		*/
if ((type == CC_ECN) &&		if ((type == CC_ECN) &&
(V_cc_do_abe \|\|		(V_cc_do_abe \|\|
((nreno != NULL) && (nreno->newreno_flags & CC_NEWRENO_BETA_ECN_ENABLED))))		((nreno != NULL) && (nreno->newreno_flags & CC_NEWRENO_BETA_ECN_ENABLED))))
factor = beta_ecn;		factor = beta_ecn;
else		else
factor = beta;		factor = beta;

/* Catch algos which mistakenly leak private signal types. */		/* Catch algos which mistakenly leak private signal types. */
KASSERT((type & CC_SIGPRIVMASK) == 0,		KASSERT((type & CC_SIGPRIVMASK) == 0,
("%s: congestion signal type 0x%08x is private\n", __func__, type));		("%s: congestion signal type 0x%08x is private\n", __func__, type));

cwin = max(((uint64_t)cwin * (uint64_t)factor) / (100ULL * (uint64_t)mss),		cwin = max(((uint64_t)cwin * (uint64_t)factor) / (100ULL * (uint64_t)mss),
2) * mss;		2) * mss;

switch (type) {		switch (type) {
case CC_NDUPACK:		case CC_NDUPACK:
if ((nreno != NULL) &&		if (nreno->newreno_flags & CC_NEWRENO_HYSTART_ENABLED) {
(nreno->newreno_flags & CC_NEWRENO_HYSTART_ENABLED)) {
/* Make sure the flags are all off we had a loss */		/* Make sure the flags are all off we had a loss */
nreno->newreno_flags &= ~CC_NEWRENO_HYSTART_ENABLED;		nreno->newreno_flags &= ~CC_NEWRENO_HYSTART_ENABLED;
nreno->newreno_flags &= ~CC_NEWRENO_HYSTART_IN_CSS;		nreno->newreno_flags &= ~CC_NEWRENO_HYSTART_IN_CSS;
}		}
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) &&
V_cc_do_abe && V_cc_abe_frlossreduce)) {		V_cc_do_abe && V_cc_abe_frlossreduce)) {
CCV(ccv, snd_ssthresh) =		CCV(ccv, snd_ssthresh) =
((uint64_t)CCV(ccv, snd_ssthresh) *		((uint64_t)CCV(ccv, snd_ssthresh) *
(uint64_t)beta) / (uint64_t)beta_ecn;		(uint64_t)beta) / (uint64_t)beta_ecn;
}		}
if (!IN_CONGRECOVERY(CCV(ccv, t_flags)))		if (!IN_CONGRECOVERY(CCV(ccv, t_flags)))
CCV(ccv, snd_ssthresh) = cwin;		CCV(ccv, snd_ssthresh) = cwin;
ENTER_RECOVERY(CCV(ccv, t_flags));		ENTER_RECOVERY(CCV(ccv, t_flags));
}		}
break;		break;
case CC_ECN:		case CC_ECN:
if ((nreno != NULL) &&		if (nreno->newreno_flags & CC_NEWRENO_HYSTART_ENABLED) {
(nreno->newreno_flags & CC_NEWRENO_HYSTART_ENABLED)) {
/* Make sure the flags are all off we had a loss */		/* Make sure the flags are all off we had a loss */
nreno->newreno_flags &= ~CC_NEWRENO_HYSTART_ENABLED;		nreno->newreno_flags &= ~CC_NEWRENO_HYSTART_ENABLED;
nreno->newreno_flags &= ~CC_NEWRENO_HYSTART_IN_CSS;		nreno->newreno_flags &= ~CC_NEWRENO_HYSTART_IN_CSS;
}		}
if (!IN_CONGRECOVERY(CCV(ccv, t_flags))) {		if (!IN_CONGRECOVERY(CCV(ccv, t_flags))) {
CCV(ccv, snd_ssthresh) = cwin;		CCV(ccv, snd_ssthresh) = cwin;
CCV(ccv, snd_cwnd) = cwin;		CCV(ccv, snd_cwnd) = cwin;
ENTER_CONGRECOVERY(CCV(ccv, t_flags));		ENTER_CONGRECOVERY(CCV(ccv, t_flags));
}		}
break;		break;
case CC_RTO:		case CC_RTO:
CCV(ccv, snd_ssthresh) = max(min(CCV(ccv, snd_wnd),		CCV(ccv, snd_ssthresh) = max(min(CCV(ccv, snd_wnd),
CCV(ccv, snd_cwnd)) / 2 / mss,		CCV(ccv, snd_cwnd)) / 2 / mss,
2) * mss;		2) * mss;
CCV(ccv, snd_cwnd) = mss;		CCV(ccv, snd_cwnd) = mss;
break;		break;
}
}

/*
* Perform any necessary tasks before we exit congestion recovery.
*/
static void
newreno_post_recovery(struct cc_var *ccv)
{
int pipe;

if (IN_FASTRECOVERY(CCV(ccv, t_flags))) {
/*
* Fast recovery will conclude after returning from this
* function. Window inflation should have left us with
* approximately snd_ssthresh outstanding data. But in case we
* would be inclined to send a burst, better to do it via the
* slow start mechanism.
*
* XXXLAS: Find a way to do this without needing curack
*/
if (V_tcp_do_newsack)
pipe = tcp_compute_pipe(ccv->ccvc.tcp);
else
pipe = CCV(ccv, snd_max) - ccv->curack;

if (pipe < CCV(ccv, snd_ssthresh))
/*
* Ensure that cwnd does not collapse to 1 MSS under
* adverse conditons. Implements RFC6582
*/
CCV(ccv, snd_cwnd) = max(pipe, CCV(ccv, t_maxseg)) +
CCV(ccv, t_maxseg);
else
CCV(ccv, snd_cwnd) = CCV(ccv, snd_ssthresh);
}		}
}		}

static int		static int
newreno_ctl_output(struct cc_var ccv, struct sockopt sopt, void *buf)		newreno_ctl_output(struct cc_var ccv, struct sockopt sopt, void *buf)
{		{
struct newreno *nreno;		struct newreno *nreno;
struct cc_newreno_opts *opt;		struct cc_newreno_opts *opt;
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