master
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 in a hpts tick */
30#define HPTS_TICKS_PER_SLOT 10
31#define HPTS_MS_TO_SLOTS(x) ((x * 100) + 1)
32#define HPTS_USEC_TO_SLOTS(x) ((x+9) /10)
33#define HPTS_USEC_IN_SEC 1000000
34#define HPTS_MSEC_IN_SEC 1000
35#define HPTS_USEC_IN_MSEC 1000
36
37struct hpts_diag {
38 uint32_t p_hpts_active; /* bbr->flex7 x */
39 uint32_t p_nxt_slot; /* bbr->flex1 x */
40 uint32_t p_cur_slot; /* bbr->flex2 x */
41 uint32_t p_prev_slot; /* bbr->delivered */
42 uint32_t p_runningslot; /* bbr->inflight */
43 uint32_t slot_req; /* bbr->flex3 x */
44 uint32_t inp_hptsslot; /* bbr->flex4 x */
45 uint32_t slot_remaining; /* bbr->flex5 x */
46 uint32_t have_slept; /* bbr->epoch x */
47 uint32_t hpts_sleep_time; /* bbr->applimited x */
48 uint32_t yet_to_sleep; /* bbr->lt_epoch x */
49 uint32_t need_new_to; /* bbr->flex6 x */
50 uint32_t wheel_slot; /* bbr->bw_inuse x */
51 uint32_t maxslots; /* bbr->delRate x */
52 uint32_t wheel_cts; /* bbr->rttProp x */
53 int32_t co_ret; /* bbr->pkts_out x */
54 uint32_t p_curtick; /* upper bbr->cur_del_rate */
55 uint32_t p_lasttick; /* lower bbr->cur_del_rate */
56 uint8_t p_on_min_sleep; /* bbr->flex8 x */
57};
58
59/* Magic flags to tell whats cooking on the pacing wheel */
60#define PACE_TMR_DELACK 0x01 /* Delayed ack timer running */
61#define PACE_TMR_RACK 0x02 /* RACK timer running */
62#define PACE_TMR_TLP 0x04 /* TLP timer running */
63#define PACE_TMR_RXT 0x08 /* Retransmit timer running */
64#define PACE_TMR_PERSIT 0x10 /* Persists timer running */
65#define PACE_TMR_KEEP 0x20 /* Keep alive timer running */
66#define PACE_PKT_OUTPUT 0x40 /* Output Packets being paced */
67#define PACE_TMR_MASK (PACE_TMR_KEEP|PACE_TMR_PERSIT|PACE_TMR_RXT|PACE_TMR_TLP|PACE_TMR_RACK|PACE_TMR_DELACK)
68
69#define DEFAULT_CONNECTION_THESHOLD 100
70
71/*
72 * When using the hpts, a TCP stack must make sure
73 * that once a INP_DROPPED flag is applied to a INP
74 * that it does not expect tcp_output() to ever be
75 * called by the hpts. The hpts will *not* call
76 * any output (or input) functions on a TCB that
77 * is in the DROPPED state.
78 *
79 * This implies final ACK's and RST's that might
80 * be sent when a TCB is still around must be
81 * sent from a routine like tcp_respond().
82 */
83#define LOWEST_SLEEP_ALLOWED 50
84#define DEFAULT_MIN_SLEEP 250 /* How many usec's is default for hpts sleep
85 * this determines min granularity of the
86 * hpts. If 1, granularity is 10useconds at
87 * the cost of more CPU (context switching).
88 * Note do not set this to 0.
89 */
90#define DYNAMIC_MIN_SLEEP DEFAULT_MIN_SLEEP
91#define DYNAMIC_MAX_SLEEP 5000 /* 5ms */
92
93/* Thresholds for raising/lowering sleep */
94#define TICKS_INDICATE_MORE_SLEEP 100 /* This would be 1ms */
95#define TICKS_INDICATE_LESS_SLEEP 1000 /* This would indicate 10ms */
96/**
97 *
98 * Dynamic adjustment of sleeping times is done in "new" mode
99 * where we are depending on syscall returns and lro returns
100 * to push hpts forward mainly and the timer is only a backstop.
101 *
102 * When we are in the "new" mode i.e. conn_cnt > conn_cnt_thresh
103 * then we do a dynamic adjustment on the time we sleep.
104 * Our threshold is if the lateness of the first client served (in ticks) is
105 * greater than or equal too ticks_indicate_more_sleep (10ms
106 * or 10000 ticks). If we were that late, the actual sleep time
107 * is adjusted down by 50%. If the ticks_ran is less than
108 * ticks_indicate_more_sleep (100 ticks or 1000usecs).
109 *
110 */
111
112#ifdef _KERNEL
113void tcp_hpts_init(struct tcpcb *);
114void tcp_hpts_remove(struct tcpcb *);
115static inline bool
116tcp_in_hpts(struct tcpcb *tp)
117{
118 return ((tp->t_in_hpts == IHPTS_ONQUEUE) ||
119 ((tp->t_in_hpts == IHPTS_MOVING) &&
120 (tp->t_hpts_slot != -1)));
121}
122
123/*
124 * To insert a TCB on the hpts you *must* be holding the
125 * INP_WLOCK(). The hpts insert code will then acqurire
126 * the hpts's lock and insert the TCB on the requested
127 * slot possibly waking up the hpts if you are requesting
128 * a time earlier than what the hpts is sleeping to (if
129 * the hpts is sleeping). You may check the inp->inp_in_hpts
130 * flag without the hpts lock. The hpts is the only one
131 * that will clear this flag holding only the hpts lock. This
132 * means that in your tcp_output() routine when you test for
133 * it to be 1 (so you wont call output) it may be transitioning
134 * to 0 (by the hpts). That will be fine since that will just
135 * mean an extra call to tcp_output that most likely will find
136 * the call you executed (when the mis-match occurred) will have
137 * put the TCB back on the hpts and it will return. If your
138 * call did not add it back to the hpts then you will either
139 * over-send or the cwnd will block you from sending more.
140 *
141 * Note you should also be holding the INP_WLOCK() when you
142 * call the remove from the hpts as well. Thoug usually
143 * you are either doing this from a timer, where you need
144 * that INP_WLOCK() or from destroying your TCB where again
145 * you should already have the INP_WLOCK().
146 */
147uint32_t tcp_hpts_insert_diag(struct tcpcb *tp, uint32_t slot, int32_t line,
148 struct hpts_diag *diag);
149#define tcp_hpts_insert(inp, slot) \
150 tcp_hpts_insert_diag((inp), (slot), __LINE__, NULL)
151
152void __tcp_set_hpts(struct tcpcb *tp, int32_t line);
153#define tcp_set_hpts(a) __tcp_set_hpts(a, __LINE__)
154
155void tcp_set_inp_to_drop(struct inpcb *inp, uint16_t reason);
156
157void tcp_lro_hpts_init(void);
158void tcp_lro_hpts_uninit(void);
159
160extern int32_t tcp_min_hptsi_time;
161
162#endif /* _KERNEL */
163
164/*
165 * The following functions should also be available
166 * to userspace as well.
167 */
168static __inline uint32_t
169tcp_tv_to_hptstick(const struct timeval *sv)
170{
171 return ((sv->tv_sec * 100000) + (sv->tv_usec / HPTS_TICKS_PER_SLOT));
172}
173
174static __inline uint32_t
175tcp_tv_to_usectick(const struct timeval *sv)
176{
177 return ((uint32_t) ((sv->tv_sec * HPTS_USEC_IN_SEC) + sv->tv_usec));
178}
179
180static __inline uint32_t
181tcp_tv_to_mssectick(const struct timeval *sv)
182{
183 return ((uint32_t) ((sv->tv_sec * HPTS_MSEC_IN_SEC) + (sv->tv_usec/HPTS_USEC_IN_MSEC)));
184}
185
186static __inline uint64_t
187tcp_tv_to_lusectick(const struct timeval *sv)
188{
189 return ((uint64_t)((sv->tv_sec * HPTS_USEC_IN_SEC) + sv->tv_usec));
190}
191
192#ifdef _KERNEL
193
194extern int32_t tcp_min_hptsi_time;
195
196static inline int32_t
197get_hpts_min_sleep_time(void)
198{
199 return (tcp_min_hptsi_time + HPTS_TICKS_PER_SLOT);
200}
201
202static __inline uint32_t
203tcp_gethptstick(struct timeval *sv)
204{
205 struct timeval tv;
206
207 if (sv == NULL)
208 sv = &tv;
209 microuptime(sv);
210 return (tcp_tv_to_hptstick(sv));
211}
212
213static __inline uint64_t
214tcp_get_u64_usecs(struct timeval *tv)
215{
216 struct timeval tvd;
217
218 if (tv == NULL)
219 tv = &tvd;
220 microuptime(tv);
221 return (tcp_tv_to_lusectick(tv));
222}
223
224static __inline uint32_t
225tcp_get_usecs(struct timeval *tv)
226{
227 struct timeval tvd;
228
229 if (tv == NULL)
230 tv = &tvd;
231 microuptime(tv);
232 return (tcp_tv_to_usectick(tv));
233}
234
235#endif /* _KERNEL */
236#endif /* __tcp_hpts_h__ */