xref: /freebsd/sys/netinet/tcp_hpts.h (revision bf48bc994a92850f7717b79da3a10a80725073bd)
1 /*-
2  * Copyright (c) 2016-2018 Netflix, Inc.
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions
6  * are met:
7  * 1. Redistributions of source code must retain the above copyright
8  *    notice, this list of conditions and the following disclaimer.
9  * 2. Redistributions in binary form must reproduce the above copyright
10  *    notice, this list of conditions and the following disclaimer in the
11  *    documentation and/or other materials provided with the distribution.
12  *
13  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
14  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
17  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23  * SUCH DAMAGE.
24  */
25 
26 #ifndef __tcp_hpts_h__
27 #define __tcp_hpts_h__
28 
29 /* Number of useconds represented by an hpts slot */
30 #define HPTS_USECS_PER_SLOT 10
31 #define HPTS_USEC_IN_SEC 1000000
32 #define HPTS_MSEC_IN_SEC 1000
33 #define HPTS_USEC_IN_MSEC 1000
34 
35 static inline uint32_t
tcp_tv_to_usec(const struct timeval * sv)36 tcp_tv_to_usec(const struct timeval *sv)
37 {
38 	return ((uint32_t) ((sv->tv_sec * HPTS_USEC_IN_SEC) + sv->tv_usec));
39 }
40 
41 static inline uint32_t
tcp_tv_to_msec(const struct timeval * sv)42 tcp_tv_to_msec(const struct timeval *sv)
43 {
44 	return ((uint32_t) ((sv->tv_sec * HPTS_MSEC_IN_SEC) + (sv->tv_usec/HPTS_USEC_IN_MSEC)));
45 }
46 
47 static inline uint64_t
tcp_tv_to_lusec(const struct timeval * sv)48 tcp_tv_to_lusec(const struct timeval *sv)
49 {
50 	return ((uint64_t)((sv->tv_sec * HPTS_USEC_IN_SEC) + sv->tv_usec));
51 }
52 
53 struct hpts_diag {
54 	uint32_t p_hpts_active; 	/* bbr->flex7 x */
55 	uint32_t p_nxt_slot;		/* bbr->flex1 x */
56 	uint32_t p_cur_slot;		/* bbr->flex2 x */
57 	uint32_t p_prev_slot;		/* bbr->delivered */
58 	uint32_t p_runningslot;		/* bbr->inflight */
59 	uint32_t slot_req;		/* bbr->flex3 x */
60 	uint32_t inp_hptsslot;		/* bbr->flex4 x */
61 	uint32_t time_remaining;	/* bbr->flex5 x */
62 	uint32_t have_slept;		/* bbr->epoch x */
63 	uint32_t hpts_sleep_time;	/* bbr->applimited x */
64 	uint32_t yet_to_sleep;		/* bbr->lt_epoch x */
65 	uint32_t need_new_to;		/* bbr->flex6 x  */
66 	uint32_t wheel_slot;		/* bbr->bw_inuse x */
67 	uint32_t maxslots;		/* bbr->delRate x */
68 	uint32_t wheel_cts;		/* bbr->rttProp x */
69 	int32_t co_ret; 		/* bbr->pkts_out x */
70 	uint8_t p_on_min_sleep; 	/* bbr->flex8 x */
71 };
72 
73 /* Magic flags to tell whats cooking on the pacing wheel */
74 #define PACE_TMR_DELACK 0x01	/* Delayed ack timer running */
75 #define PACE_TMR_RACK   0x02	/* RACK timer running */
76 #define PACE_TMR_TLP    0x04	/* TLP timer running */
77 #define PACE_TMR_RXT    0x08	/* Retransmit timer running */
78 #define PACE_TMR_PERSIT 0x10	/* Persists timer running */
79 #define PACE_TMR_KEEP   0x20	/* Keep alive timer running */
80 #define PACE_PKT_OUTPUT 0x40	/* Output Packets being paced */
81 #define PACE_TMR_MASK   (PACE_TMR_KEEP|PACE_TMR_PERSIT|PACE_TMR_RXT|PACE_TMR_TLP|PACE_TMR_RACK|PACE_TMR_DELACK)
82 
83 #ifdef _KERNEL
84 
85 extern struct tcp_hptsi *tcp_hptsi_pace;
86 
87 /*
88  * The following are the definitions for the kernel HPTS interface for managing
89  * the HPTS ring and the TCBs on it.
90 */
91 
92 void __tcp_hpts_init(struct tcp_hptsi *pace, struct tcpcb *);
93 #define tcp_hpts_init(tp) __tcp_hpts_init(tcp_hptsi_pace, tp)
94 
95 void __tcp_hpts_remove(struct tcp_hptsi *pace, struct tcpcb *);
96 #define tcp_hpts_remove(tp) __tcp_hpts_remove(tcp_hptsi_pace, tp)
97 
98 static inline bool
tcp_in_hpts(struct tcpcb * tp)99 tcp_in_hpts(struct tcpcb *tp)
100 {
101 	return ((tp->t_in_hpts == IHPTS_ONQUEUE) ||
102 		((tp->t_in_hpts == IHPTS_MOVING) &&
103 		 (tp->t_hpts_slot != -1)));
104 }
105 
106 /*
107  * To insert a TCB on the hpts you *must* be holding the
108  * INP_WLOCK(). The hpts insert code will then acqurire
109  * the hpts's lock and insert the TCB on the requested
110  * slot possibly waking up the hpts if you are requesting
111  * a time earlier than what the hpts is sleeping to (if
112  * the hpts is sleeping). You may check the inp->inp_in_hpts
113  * flag without the hpts lock. The hpts is the only one
114  * that will clear this flag holding only the hpts lock. This
115  * means that in your tcp_output() routine when you test for
116  * it to be 1 (so you wont call output) it may be transitioning
117  * to 0 (by the hpts). That will be fine since that will just
118  * mean an extra call to tcp_output that most likely will find
119  * the call you executed (when the mis-match occurred) will have
120  * put the TCB back on the hpts and it will return. If your
121  * call did not add it back to the hpts then you will either
122  * over-send or the cwnd will block you from sending more.
123  *
124  * Note you should also be holding the INP_WLOCK() when you
125  * call the remove from the hpts as well. Thoug usually
126  * you are either doing this from a timer, where you need
127  * that INP_WLOCK() or from destroying your TCB where again
128  * you should already have the INP_WLOCK().
129  */
130 void __tcp_hpts_insert(struct tcp_hptsi *pace, struct tcpcb *tp, uint32_t usecs,
131 	struct hpts_diag *diag);
132 #define	tcp_hpts_insert(tp, usecs, diag)	\
133 	__tcp_hpts_insert(tcp_hptsi_pace, (tp), (usecs), (diag))
134 
135 void __tcp_set_hpts(struct tcp_hptsi *pace, struct tcpcb *tp);
136 #define tcp_set_hpts(tp) __tcp_set_hpts(tcp_hptsi_pace, tp)
137 
138 extern int32_t tcp_min_hptsi_time;
139 
140 static inline int32_t
get_hpts_min_sleep_time(void)141 get_hpts_min_sleep_time(void)
142 {
143 	return (tcp_min_hptsi_time + HPTS_USECS_PER_SLOT);
144 }
145 
146 static inline uint64_t
tcp_get_u64_usecs(struct timeval * tv)147 tcp_get_u64_usecs(struct timeval *tv)
148 {
149 	struct timeval tvd;
150 
151 	if (tv == NULL)
152 		tv = &tvd;
153 	microuptime(tv);
154 	return (tcp_tv_to_lusec(tv));
155 }
156 
157 static inline uint32_t
tcp_get_usecs(struct timeval * tv)158 tcp_get_usecs(struct timeval *tv)
159 {
160 	struct timeval tvd;
161 
162 	if (tv == NULL)
163 		tv = &tvd;
164 	microuptime(tv);
165 	return (tcp_tv_to_usec(tv));
166 }
167 
168 #endif /* _KERNEL */
169 #endif /* __tcp_hpts_h__ */
170