2 * Copyright (c) 2011 The University of Melbourne
5 * This software was developed by Julien Ridoux at the University of Melbourne
6 * under sponsorship from the FreeBSD Foundation.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 #ifndef _SYS_TIMEFF_H_
33 #define _SYS_TIMEFF_H_
35 #include <sys/_ffcounter.h>
38 * Feed-forward clock estimate
39 * Holds time mark as a ffcounter and conversion to bintime based on current
40 * timecounter period and offset estimate passed by the synchronization daemon.
41 * Provides time of last daemon update, clock status and bound on error.
43 struct ffclock_estimate {
44 struct bintime update_time; /* Time of last estimates update. */
45 ffcounter update_ffcount; /* Counter value at last update. */
46 ffcounter leapsec_next; /* Counter value of next leap second. */
47 uint64_t period; /* Estimate of counter period. */
48 uint32_t errb_abs; /* Bound on absolute clock error [ns]. */
49 uint32_t errb_rate; /* Bound on counter rate error [ps/s]. */
50 uint32_t status; /* Clock status. */
51 int16_t leapsec_total; /* All leap seconds seen so far. */
52 int8_t leapsec; /* Next leap second (in {-1,0,1}). */
58 /* Define the kern.sysclock sysctl tree. */
59 SYSCTL_DECL(_kern_sysclock);
61 /* Define the kern.sysclock.ffclock sysctl tree. */
62 SYSCTL_DECL(_kern_sysclock_ffclock);
65 * Index into the sysclocks array for obtaining the ASCII name of a particular
68 #define SYSCLOCK_FBCK 0
69 #define SYSCLOCK_FFWD 1
70 extern int sysclock_active;
73 * Parameters of counter characterisation required by feed-forward algorithms.
75 #define FFCLOCK_SKM_SCALE 1024
78 * Feed-forward clock status
80 #define FFCLOCK_STA_UNSYNC 1
81 #define FFCLOCK_STA_WARMUP 2
84 * Clock flags to select how the feed-forward counter is converted to absolute
85 * time by ffclock_convert_abs().
86 * FAST: do not read the hardware counter, return feed-forward clock time
87 * at last tick. The time returned has the resolution of the kernel
89 * LERP: linear interpolation of ffclock time to guarantee monotonic time.
90 * LEAPSEC: include leap seconds.
91 * UPTIME: removes time of boot.
93 #define FFCLOCK_FAST 1
94 #define FFCLOCK_LERP 2
95 #define FFCLOCK_LEAPSEC 4
96 #define FFCLOCK_UPTIME 8
98 /* Resets feed-forward clock from RTC */
99 void ffclock_reset_clock(struct timespec *ts);
102 * Return the current value of the feed-forward clock counter. Essential to
103 * measure time interval in counter units. If a fast timecounter is used by the
104 * system, may also allow fast but accurate timestamping.
106 void ffclock_read_counter(ffcounter *ffcount);
109 * Retrieve feed-forward counter value and time of last kernel tick. This
110 * accepts the FFCLOCK_LERP flag.
112 void ffclock_last_tick(ffcounter *ffcount, struct bintime *bt, uint32_t flags);
115 * Low level routines to convert a counter timestamp into absolute time and a
116 * counter timestamp interval into an interval in seconds. The absolute time
117 * conversion accepts the FFCLOCK_LERP flag.
119 void ffclock_convert_abs(ffcounter ffcount, struct bintime *bt, uint32_t flags);
120 void ffclock_convert_diff(ffcounter ffdelta, struct bintime *bt);
123 * Feed-forward clock routines.
125 * These functions rely on the timecounters and ffclock_estimates stored in
126 * fftimehands. Note that the error_bound parameter is not the error of the
127 * clock but an upper bound on the error of the absolute time or time interval
130 * ffclock_abstime(): retrieves current time as counter value and convert this
131 * timestamp in seconds. The value (in seconds) of the converted timestamp
132 * depends on the flags passed: for a given counter value, different
133 * conversions are possible. Different clock models can be selected by
134 * combining flags (for example (FFCLOCK_LERP|FFCLOCK_UPTIME) produces
135 * linearly interpolated uptime).
136 * ffclock_difftime(): computes a time interval in seconds based on an interval
137 * measured in ffcounter units. This should be the preferred way to measure
138 * small time intervals very accurately.
140 void ffclock_abstime(ffcounter *ffcount, struct bintime *bt,
141 struct bintime *error_bound, uint32_t flags);
142 void ffclock_difftime(ffcounter ffdelta, struct bintime *bt,
143 struct bintime *error_bound);
146 * Wrapper routines to return current absolute time using the feed-forward
147 * clock. These functions are named after those defined in <sys/time.h>, which
148 * contains a description of the original ones.
150 void ffclock_bintime(struct bintime *bt);
151 void ffclock_nanotime(struct timespec *tsp);
152 void ffclock_microtime(struct timeval *tvp);
154 void ffclock_getbintime(struct bintime *bt);
155 void ffclock_getnanotime(struct timespec *tsp);
156 void ffclock_getmicrotime(struct timeval *tvp);
158 void ffclock_binuptime(struct bintime *bt);
159 void ffclock_nanouptime(struct timespec *tsp);
160 void ffclock_microuptime(struct timeval *tvp);
162 void ffclock_getbinuptime(struct bintime *bt);
163 void ffclock_getnanouptime(struct timespec *tsp);
164 void ffclock_getmicrouptime(struct timeval *tvp);
167 * Wrapper routines to convert a time interval specified in ffcounter units into
168 * seconds using the current feed-forward clock estimates.
170 void ffclock_bindifftime(ffcounter ffdelta, struct bintime *bt);
171 void ffclock_nanodifftime(ffcounter ffdelta, struct timespec *tsp);
172 void ffclock_microdifftime(ffcounter ffdelta, struct timeval *tvp);
175 * When FFCLOCK is enabled in the kernel, [get]{bin,nano,micro}[up]time() become
176 * wrappers around equivalent feedback or feed-forward functions. Provide access
177 * outside of kern_tc.c to the feedback clock equivalent functions for
178 * specialised use i.e. these are not for general consumption.
180 void fbclock_bintime(struct bintime *bt);
181 void fbclock_nanotime(struct timespec *tsp);
182 void fbclock_microtime(struct timeval *tvp);
184 void fbclock_getbintime(struct bintime *bt);
185 void fbclock_getnanotime(struct timespec *tsp);
186 void fbclock_getmicrotime(struct timeval *tvp);
188 void fbclock_binuptime(struct bintime *bt);
189 void fbclock_nanouptime(struct timespec *tsp);
190 void fbclock_microuptime(struct timeval *tvp);
192 void fbclock_getbinuptime(struct bintime *bt);
193 void fbclock_getnanouptime(struct timespec *tsp);
194 void fbclock_getmicrouptime(struct timeval *tvp);
197 * Public system clock wrapper API which allows consumers to select which clock
198 * to obtain time from, independent of the current default system clock. These
199 * wrappers should be used instead of directly calling the underlying fbclock_
200 * or ffclock_ functions.
203 bintime_fromclock(struct bintime *bt, int whichclock)
206 if (whichclock == SYSCLOCK_FFWD)
213 nanotime_fromclock(struct timespec *tsp, int whichclock)
216 if (whichclock == SYSCLOCK_FFWD)
217 ffclock_nanotime(tsp);
219 fbclock_nanotime(tsp);
223 microtime_fromclock(struct timeval *tvp, int whichclock)
226 if (whichclock == SYSCLOCK_FFWD)
227 ffclock_microtime(tvp);
229 fbclock_microtime(tvp);
233 getbintime_fromclock(struct bintime *bt, int whichclock)
236 if (whichclock == SYSCLOCK_FFWD)
237 ffclock_getbintime(bt);
239 fbclock_getbintime(bt);
243 getnanotime_fromclock(struct timespec *tsp, int whichclock)
246 if (whichclock == SYSCLOCK_FFWD)
247 ffclock_getnanotime(tsp);
249 fbclock_getnanotime(tsp);
253 getmicrotime_fromclock(struct timeval *tvp, int whichclock)
256 if (whichclock == SYSCLOCK_FFWD)
257 ffclock_getmicrotime(tvp);
259 fbclock_getmicrotime(tvp);
263 binuptime_fromclock(struct bintime *bt, int whichclock)
266 if (whichclock == SYSCLOCK_FFWD)
267 ffclock_binuptime(bt);
269 fbclock_binuptime(bt);
273 nanouptime_fromclock(struct timespec *tsp, int whichclock)
276 if (whichclock == SYSCLOCK_FFWD)
277 ffclock_nanouptime(tsp);
279 fbclock_nanouptime(tsp);
283 microuptime_fromclock(struct timeval *tvp, int whichclock)
286 if (whichclock == SYSCLOCK_FFWD)
287 ffclock_microuptime(tvp);
289 fbclock_microuptime(tvp);
293 getbinuptime_fromclock(struct bintime *bt, int whichclock)
296 if (whichclock == SYSCLOCK_FFWD)
297 ffclock_getbinuptime(bt);
299 fbclock_getbinuptime(bt);
303 getnanouptime_fromclock(struct timespec *tsp, int whichclock)
306 if (whichclock == SYSCLOCK_FFWD)
307 ffclock_getnanouptime(tsp);
309 fbclock_getnanouptime(tsp);
313 getmicrouptime_fromclock(struct timeval *tvp, int whichclock)
316 if (whichclock == SYSCLOCK_FFWD)
317 ffclock_getmicrouptime(tvp);
319 fbclock_getmicrouptime(tvp);
324 /* Feed-Forward Clock system calls. */
326 int ffclock_getcounter(ffcounter *ffcount);
327 int ffclock_getestimate(struct ffclock_estimate *cest);
328 int ffclock_setestimate(struct ffclock_estimate *cest);
332 #endif /* __BSD_VISIBLE */
333 #endif /* _SYS_TIMEFF_H_ */