xref: /freebsd/sys/netinet/tcp_hpts.h (revision ce6a89e27cd190313be39bb479880aeda4778436)
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  * $FreeBSD$
26  */
27 
28 #ifndef __tcp_hpts_h__
29 #define __tcp_hpts_h__
30 
31 /*
32  * The hpts uses a 102400 wheel. The wheel
33  * defines the time in 10 usec increments (102400 x 10).
34  * This gives a range of 10usec - 1024ms to place
35  * an entry within. If the user requests more than
36  * 1.024 second, a remaineder is attached and the hpts
37  * when seeing the remainder will re-insert the
38  * inpcb forward in time from where it is until
39  * the remainder is zero.
40  */
41 
42 #define NUM_OF_HPTSI_SLOTS 102400
43 
44 TAILQ_HEAD(hptsh, inpcb);
45 
46 /* Number of useconds in a hpts tick */
47 #define HPTS_TICKS_PER_USEC 10
48 #define HPTS_MS_TO_SLOTS(x) ((x * 100) + 1)
49 #define HPTS_USEC_TO_SLOTS(x) ((x+9) /10)
50 #define HPTS_USEC_IN_SEC 1000000
51 #define HPTS_MSEC_IN_SEC 1000
52 #define HPTS_USEC_IN_MSEC 1000
53 
54 
55 struct hpts_diag {
56 	uint32_t p_hpts_active; 	/* bbr->flex7 x */
57 	uint32_t p_nxt_slot;		/* bbr->flex1 x */
58 	uint32_t p_cur_slot;		/* bbr->flex2 x */
59 	uint32_t p_prev_slot;		/* bbr->delivered */
60 	uint32_t p_runningtick;		/* bbr->inflight */
61 	uint32_t slot_req;		/* bbr->flex3 x */
62 	uint32_t inp_hptsslot;		/* bbr->flex4 x */
63 	uint32_t slot_remaining;	/* bbr->flex5 x */
64 	uint32_t have_slept;		/* bbr->epoch x */
65 	uint32_t hpts_sleep_time;	/* bbr->applimited x */
66 	uint32_t yet_to_sleep;		/* bbr->lt_epoch x */
67 	uint32_t need_new_to;		/* bbr->flex6 x  */
68 	uint32_t wheel_tick;		/* bbr->bw_inuse x */
69 	uint32_t maxticks;		/* bbr->delRate x */
70 	uint32_t wheel_cts;		/* bbr->rttProp x */
71 	int32_t co_ret; 		/* bbr->pkts_out x */
72 	uint32_t p_curtick;		/* upper bbr->cur_del_rate */
73 	uint32_t p_lasttick;		/* lower bbr->cur_del_rate */
74 	uint8_t p_on_min_sleep; 	/* bbr->flex8 x */
75 };
76 
77 /* Magic flags to tell whats cooking on the pacing wheel */
78 #define PACE_TMR_DELACK 0x01	/* Delayed ack timer running */
79 #define PACE_TMR_RACK   0x02	/* RACK timer running */
80 #define PACE_TMR_TLP    0x04	/* TLP timer running */
81 #define PACE_TMR_RXT    0x08	/* Retransmit timer running */
82 #define PACE_TMR_PERSIT 0x10	/* Persists timer running */
83 #define PACE_TMR_KEEP   0x20	/* Keep alive timer running */
84 #define PACE_PKT_OUTPUT 0x40	/* Output Packets being paced */
85 #define PACE_TMR_MASK   (PACE_TMR_KEEP|PACE_TMR_PERSIT|PACE_TMR_RXT|PACE_TMR_TLP|PACE_TMR_RACK|PACE_TMR_DELACK)
86 
87 #ifdef _KERNEL
88 /* Each hpts has its own p_mtx which is used for locking */
89 struct tcp_hpts_entry {
90 	/* Cache line 0x00 */
91 	struct mtx p_mtx;	/* Mutex for hpts */
92 	uint16_t p_hpts_active; /* Flag that says hpts is awake  */
93 	uint8_t p_hpts_wake_scheduled;	/* Have we scheduled a wakeup? */
94 	uint8_t p_wheel_complete; /* have we completed the wheel arc walk? */
95 	uint32_t p_curtick;	/* Tick in 10 us the hpts is going to */
96 	uint32_t p_runningtick; /* Current tick we are at if we are running */
97 	uint32_t p_prev_slot;	/* Previous slot we were on */
98 	uint32_t p_cur_slot;	/* Current slot in wheel hpts is draining */
99 	uint32_t p_nxt_slot;	/* The next slot outside the current range of
100 				 * slots that the hpts is running on. */
101 	int32_t p_on_queue_cnt;	/* Count on queue in this hpts */
102 	uint32_t p_lasttick;	/* Last tick before the current one */
103 	uint8_t p_direct_wake :1, /* boolean */
104 		p_on_min_sleep:1, /* boolean */
105 		p_avail:6;
106 	uint8_t p_fill[3];	  /* Fill to 32 bits */
107 	/* Cache line 0x40 */
108 	void *p_inp;
109 	struct hptsh p_input;	/* For the tcp-input runner */
110 	/* Hptsi wheel */
111 	struct hptsh *p_hptss;
112 	int32_t p_on_inqueue_cnt; /* Count on input queue in this hpts */
113 	uint32_t hit_no_enobuf;
114 	uint32_t p_dyn_adjust;
115 	uint32_t p_hpts_sleep_time;	/* Current sleep interval having a max
116 					 * of 255ms */
117 	uint32_t overidden_sleep;	/* what was overrided by min-sleep for logging */
118 	uint32_t saved_lasttick;	/* for logging */
119 	uint32_t saved_curtick;		/* for logging */
120 	uint32_t saved_curslot;		/* for logging */
121 	uint32_t saved_prev_slot;       /* for logging */
122 	uint32_t p_delayed_by;	/* How much were we delayed by */
123 	/* Cache line 0x80 */
124 	struct sysctl_ctx_list hpts_ctx;
125 	struct sysctl_oid *hpts_root;
126 	struct intr_event *ie;
127 	void *ie_cookie;
128 	uint16_t p_num;		/* The hpts number one per cpu */
129 	uint16_t p_cpu;		/* The hpts CPU */
130 	/* There is extra space in here */
131 	/* Cache line 0x100 */
132 	struct callout co __aligned(CACHE_LINE_SIZE);
133 }               __aligned(CACHE_LINE_SIZE);
134 
135 struct tcp_hptsi {
136 	struct proc *rp_proc;	/* Process structure for hpts */
137 	struct tcp_hpts_entry **rp_ent;	/* Array of hptss */
138 	uint32_t rp_num_hptss;	/* Number of hpts threads */
139 };
140 
141 #endif
142 
143 #define HPTS_REMOVE_INPUT  0x01
144 #define HPTS_REMOVE_OUTPUT 0x02
145 #define HPTS_REMOVE_ALL    (HPTS_REMOVE_INPUT | HPTS_REMOVE_OUTPUT)
146 
147 /*
148  * When using the hpts, a TCP stack must make sure
149  * that once a INP_DROPPED flag is applied to a INP
150  * that it does not expect tcp_output() to ever be
151  * called by the hpts. The hpts will *not* call
152  * any output (or input) functions on a TCB that
153  * is in the DROPPED state.
154  *
155  * This implies final ACK's and RST's that might
156  * be sent when a TCB is still around must be
157  * sent from a routine like tcp_respond().
158  */
159 #define DEFAULT_MIN_SLEEP 250	/* How many usec's is default for hpts sleep
160 				 * this determines min granularity of the
161 				 * hpts. If 0, granularity is 10useconds at
162 				 * the cost of more CPU (context switching). */
163 #ifdef _KERNEL
164 #define HPTS_MTX_ASSERT(hpts) mtx_assert(&(hpts)->p_mtx, MA_OWNED)
165 struct tcp_hpts_entry *tcp_hpts_lock(struct inpcb *inp);
166 struct tcp_hpts_entry *tcp_input_lock(struct inpcb *inp);
167 int __tcp_queue_to_hpts_immediate(struct inpcb *inp, int32_t line);
168 #define tcp_queue_to_hpts_immediate(a)__tcp_queue_to_hpts_immediate(a, __LINE__)
169 
170 struct tcp_hpts_entry *tcp_cur_hpts(struct inpcb *inp);
171 #define tcp_hpts_remove(a, b) __tcp_hpts_remove(a, b, __LINE__)
172 void __tcp_hpts_remove(struct inpcb *inp, int32_t flags, int32_t line);
173 
174 /*
175  * To insert a TCB on the hpts you *must* be holding the
176  * INP_WLOCK(). The hpts insert code will then acqurire
177  * the hpts's lock and insert the TCB on the requested
178  * slot possibly waking up the hpts if you are requesting
179  * a time earlier than what the hpts is sleeping to (if
180  * the hpts is sleeping). You may check the inp->inp_in_hpts
181  * flag without the hpts lock. The hpts is the only one
182  * that will clear this flag holding only the hpts lock. This
183  * means that in your tcp_output() routine when you test for
184  * it to be 1 (so you wont call output) it may be transitioning
185  * to 0 (by the hpts). That will be fine since that will just
186  * mean an extra call to tcp_output that most likely will find
187  * the call you executed (when the mis-match occured) will have
188  * put the TCB back on the hpts and it will return. If your
189  * call did not add it back to the hpts then you will either
190  * over-send or the cwnd will block you from sending more.
191  *
192  * Note you should also be holding the INP_WLOCK() when you
193  * call the remove from the hpts as well. Thoug usually
194  * you are either doing this from a timer, where you need
195  * that INP_WLOCK() or from destroying your TCB where again
196  * you should already have the INP_WLOCK().
197  */
198 uint32_t __tcp_hpts_insert(struct inpcb *inp, uint32_t slot, int32_t line);
199 #define tcp_hpts_insert(a, b) __tcp_hpts_insert(a, b, __LINE__)
200 
201 uint32_t
202 tcp_hpts_insert_diag(struct inpcb *inp, uint32_t slot, int32_t line, struct hpts_diag *diag);
203 
204 int
205     __tcp_queue_to_input_locked(struct inpcb *inp, struct tcp_hpts_entry *hpts, int32_t line);
206 #define tcp_queue_to_input_locked(a, b) __tcp_queue_to_input_locked(a, b, __LINE__);
207 int
208 __tcp_queue_to_input(struct inpcb *inp, int32_t line);
209 #define tcp_queue_to_input(a) __tcp_queue_to_input(a, __LINE__)
210 
211 uint16_t tcp_hpts_delayedby(struct inpcb *inp);
212 
213 void __tcp_set_hpts(struct inpcb *inp, int32_t line);
214 #define tcp_set_hpts(a) __tcp_set_hpts(a, __LINE__)
215 
216 void __tcp_set_inp_to_drop(struct inpcb *inp, uint16_t reason, int32_t line);
217 #define tcp_set_inp_to_drop(a, b) __tcp_set_inp_to_drop(a, b, __LINE__)
218 
219 extern int32_t tcp_min_hptsi_time;
220 
221 static __inline uint32_t
222 tcp_tv_to_hptstick(struct timeval *sv)
223 {
224 	return ((sv->tv_sec * 100000) + (sv->tv_usec / 10));
225 }
226 
227 static __inline uint32_t
228 tcp_gethptstick(struct timeval *sv)
229 {
230 	struct timeval tv;
231 
232 	if (sv == NULL)
233 		sv = &tv;
234 	microuptime(sv);
235 	return (tcp_tv_to_hptstick(sv));
236 }
237 
238 static __inline uint32_t
239 tcp_tv_to_usectick(struct timeval *sv)
240 {
241 	return ((uint32_t) ((sv->tv_sec * HPTS_USEC_IN_SEC) + sv->tv_usec));
242 }
243 
244 static __inline uint32_t
245 tcp_tv_to_mssectick(struct timeval *sv)
246 {
247 	return ((uint32_t) ((sv->tv_sec * HPTS_MSEC_IN_SEC) + (sv->tv_usec/HPTS_USEC_IN_MSEC)));
248 }
249 
250 static __inline void
251 tcp_hpts_unlock(struct tcp_hpts_entry *hpts)
252 {
253 	mtx_unlock(&hpts->p_mtx);
254 }
255 
256 static __inline uint32_t
257 tcp_get_usecs(struct timeval *tv)
258 {
259 	struct timeval tvd;
260 
261 	if (tv == NULL)
262 		tv = &tvd;
263 	microuptime(tv);
264 	return (tcp_tv_to_usectick(tv));
265 }
266 
267 #endif /* _KERNEL */
268 #endif /* __tcp_hpts_h__ */
269