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Commit | Line | Data |
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fc235a3f ML |
1 | /* |
2 | chronyd/chronyc - Programs for keeping computer clocks accurate. | |
3 | ||
4 | ********************************************************************** | |
33967780 | 5 | * Copyright (C) Miroslav Lichvar 2014-2015 |
fc235a3f ML |
6 | * |
7 | * This program is free software; you can redistribute it and/or modify | |
8 | * it under the terms of version 2 of the GNU General Public License as | |
9 | * published by the Free Software Foundation. | |
10 | * | |
11 | * This program is distributed in the hope that it will be useful, but | |
12 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | * General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU General Public License along | |
17 | * with this program; if not, write to the Free Software Foundation, Inc., | |
18 | * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. | |
19 | * | |
20 | ********************************************************************** | |
21 | ||
22 | ======================================================================= | |
23 | ||
24 | Generic driver functions to complete system-specific drivers | |
25 | */ | |
26 | ||
27 | #include "config.h" | |
28 | ||
29 | #include "sysincl.h" | |
30 | ||
31 | #include "sys_generic.h" | |
32 | ||
9cf78b97 | 33 | #include "conf.h" |
fc235a3f ML |
34 | #include "local.h" |
35 | #include "localp.h" | |
36 | #include "logging.h" | |
400820d3 | 37 | #include "privops.h" |
fc235a3f ML |
38 | #include "sched.h" |
39 | #include "util.h" | |
40 | ||
41 | /* ================================================== */ | |
42 | ||
02cbe5e1 | 43 | /* System clock drivers */ |
fc235a3f ML |
44 | static lcl_ReadFrequencyDriver drv_read_freq; |
45 | static lcl_SetFrequencyDriver drv_set_freq; | |
02cbe5e1 | 46 | static lcl_SetSyncStatusDriver drv_set_sync_status; |
d6fdae5f ML |
47 | static lcl_AccrueOffsetDriver drv_accrue_offset; |
48 | static lcl_OffsetCorrectionDriver drv_get_offset_correction; | |
fc235a3f ML |
49 | |
50 | /* Current frequency as requested by the local module (in ppm) */ | |
51 | static double base_freq; | |
52 | ||
53 | /* Maximum frequency that can be set by drv_set_freq (in ppm) */ | |
54 | static double max_freq; | |
55 | ||
56 | /* Maximum expected delay in the actual frequency change (e.g. kernel ticks) | |
57 | in local time */ | |
58 | static double max_freq_change_delay; | |
59 | ||
9cf78b97 ML |
60 | /* Maximum allowed frequency offset relative to the base frequency */ |
61 | static double max_corr_freq; | |
62 | ||
fc235a3f ML |
63 | /* Amount of outstanding offset to process */ |
64 | static double offset_register; | |
65 | ||
66 | /* Minimum offset to correct */ | |
67 | #define MIN_OFFSET_CORRECTION 1.0e-9 | |
68 | ||
69 | /* Current frequency offset between base_freq and the real clock frequency | |
70 | as set by drv_set_freq (not in ppm) */ | |
71 | static double slew_freq; | |
72 | ||
fc235a3f | 73 | /* Time (raw) of last update of slewing frequency and offset */ |
d0dfa1de | 74 | static struct timespec slew_start; |
fc235a3f | 75 | |
af8e4a51 ML |
76 | /* Limits for the slew length */ |
77 | #define MIN_SLEW_DURATION 1.0 | |
78 | #define MAX_SLEW_DURATION 1.0e4 | |
fc235a3f | 79 | |
0076458e | 80 | /* Scheduler timeout ID for ending of the currently running slew */ |
fc235a3f | 81 | static SCH_TimeoutID slew_timeout_id; |
fc235a3f | 82 | |
2ed88c31 ML |
83 | /* Scheduled duration of the currently running slew */ |
84 | static double slew_duration; | |
85 | ||
86 | /* Expected delay in ending of the slew due to process scheduling and | |
87 | execution time, tracked as a decaying maximum value */ | |
88 | static double slew_excess_duration; | |
89 | ||
90 | /* Maximum accepted excess duration to ignore large jumps after resuming | |
91 | suspended system and other reasons (which should be handled in the | |
92 | scheduler), a constant to determine the minimum slew duration to avoid | |
93 | oscillations due to the excess, and the decay constant */ | |
94 | #define MAX_SLEW_EXCESS_DURATION 100.0 | |
95 | #define MIN_SLEW_DURATION_EXCESS_RATIO 5.0 | |
96 | #define SLEW_EXCESS_DURATION_DECAY 0.9 | |
97 | ||
fc235a3f ML |
98 | /* Suggested offset correction rate (correction time * offset) */ |
99 | static double correction_rate; | |
100 | ||
101 | /* Maximum expected offset correction error caused by delayed change in the | |
102 | real frequency of the clock */ | |
103 | static double slew_error; | |
104 | ||
d6fdae5f ML |
105 | /* Minimum offset that the system driver can slew faster than the maximum |
106 | frequency offset that it allows to be set directly */ | |
107 | static double fastslew_min_offset; | |
108 | ||
109 | /* Maximum slew rate of the system driver */ | |
110 | static double fastslew_max_rate; | |
111 | ||
112 | /* Flag indicating that the system driver is currently slewing */ | |
113 | static int fastslew_active; | |
114 | ||
fc235a3f ML |
115 | /* ================================================== */ |
116 | ||
117 | static void handle_end_of_slew(void *anything); | |
a33a9551 | 118 | static void update_slew(void); |
fc235a3f ML |
119 | |
120 | /* ================================================== */ | |
121 | /* Adjust slew_start on clock step */ | |
122 | ||
123 | static void | |
d0dfa1de | 124 | handle_step(struct timespec *raw, struct timespec *cooked, double dfreq, |
44c9744d | 125 | double doffset, LCL_ChangeType change_type, void *anything) |
fc235a3f | 126 | { |
9cc609c4 | 127 | if (change_type == LCL_ChangeStep) { |
d0dfa1de | 128 | UTI_AddDoubleToTimespec(&slew_start, -doffset, &slew_start); |
a33a9551 | 129 | } |
fc235a3f ML |
130 | } |
131 | ||
ad942e35 ML |
132 | /* ================================================== */ |
133 | ||
d6fdae5f ML |
134 | static void |
135 | start_fastslew(void) | |
136 | { | |
137 | if (!drv_accrue_offset) | |
138 | return; | |
139 | ||
140 | drv_accrue_offset(offset_register, 0.0); | |
141 | ||
f282856c | 142 | DEBUG_LOG("fastslew offset=%e", offset_register); |
d6fdae5f ML |
143 | |
144 | offset_register = 0.0; | |
145 | fastslew_active = 1; | |
146 | } | |
147 | ||
148 | /* ================================================== */ | |
149 | ||
150 | static void | |
d0dfa1de | 151 | stop_fastslew(struct timespec *now) |
d6fdae5f ML |
152 | { |
153 | double corr; | |
154 | ||
155 | if (!drv_get_offset_correction || !fastslew_active) | |
156 | return; | |
157 | ||
158 | /* Cancel the remaining offset */ | |
159 | drv_get_offset_correction(now, &corr, NULL); | |
160 | drv_accrue_offset(corr, 0.0); | |
161 | offset_register -= corr; | |
162 | } | |
163 | ||
164 | /* ================================================== */ | |
165 | ||
ad942e35 ML |
166 | static double |
167 | clamp_freq(double freq) | |
168 | { | |
169 | if (freq > max_freq) | |
170 | return max_freq; | |
171 | if (freq < -max_freq) | |
172 | return -max_freq; | |
173 | return freq; | |
174 | } | |
175 | ||
fc235a3f ML |
176 | /* ================================================== */ |
177 | /* End currently running slew and start a new one */ | |
178 | ||
179 | static void | |
180 | update_slew(void) | |
181 | { | |
2ed88c31 | 182 | double old_slew_freq, total_freq, corr_freq, duration, excess_duration; |
d0dfa1de | 183 | struct timespec now, end_of_slew; |
fc235a3f ML |
184 | |
185 | /* Remove currently running timeout */ | |
0076458e | 186 | SCH_RemoveTimeout(slew_timeout_id); |
fc235a3f ML |
187 | |
188 | LCL_ReadRawTime(&now); | |
189 | ||
190 | /* Adjust the offset register by achieved slew */ | |
cfe706f0 | 191 | duration = UTI_DiffTimespecsToDouble(&now, &slew_start); |
fc235a3f ML |
192 | offset_register -= slew_freq * duration; |
193 | ||
d6fdae5f ML |
194 | stop_fastslew(&now); |
195 | ||
2ed88c31 ML |
196 | /* Update the maximum excess duration, decaying even when the slew did |
197 | not time out (i.e. frequency was set or offset accrued), but add a small | |
198 | value to avoid denormals */ | |
199 | slew_excess_duration = (slew_excess_duration + 1.0e-9) * SLEW_EXCESS_DURATION_DECAY; | |
200 | excess_duration = duration - slew_duration; | |
201 | if (slew_excess_duration < excess_duration && | |
202 | excess_duration <= MAX_SLEW_EXCESS_DURATION) | |
203 | slew_excess_duration = excess_duration; | |
204 | ||
205 | /* Calculate the duration of the new slew, considering the current correction | |
206 | rate and previous delays in stopping of the slew */ | |
fc235a3f | 207 | if (fabs(offset_register) < MIN_OFFSET_CORRECTION) { |
af8e4a51 | 208 | duration = MAX_SLEW_DURATION; |
fc235a3f ML |
209 | } else { |
210 | duration = correction_rate / fabs(offset_register); | |
af8e4a51 ML |
211 | if (duration < MIN_SLEW_DURATION) |
212 | duration = MIN_SLEW_DURATION; | |
2ed88c31 ML |
213 | if (duration < MIN_SLEW_DURATION_EXCESS_RATIO * slew_excess_duration) |
214 | duration = MIN_SLEW_DURATION_EXCESS_RATIO * slew_excess_duration; | |
fc235a3f ML |
215 | } |
216 | ||
217 | /* Get frequency offset needed to slew the offset in the duration | |
218 | and clamp it to the allowed maximum */ | |
219 | corr_freq = offset_register / duration; | |
9cf78b97 ML |
220 | if (corr_freq < -max_corr_freq) |
221 | corr_freq = -max_corr_freq; | |
222 | else if (corr_freq > max_corr_freq) | |
223 | corr_freq = max_corr_freq; | |
fc235a3f | 224 | |
d6fdae5f ML |
225 | /* Let the system driver perform the slew if the requested frequency |
226 | offset is too large for the frequency driver */ | |
227 | if (drv_accrue_offset && fabs(corr_freq) >= fastslew_max_rate && | |
228 | fabs(offset_register) > fastslew_min_offset) { | |
229 | start_fastslew(); | |
230 | corr_freq = 0.0; | |
231 | } | |
232 | ||
fc235a3f | 233 | /* Get the new real frequency and clamp it */ |
ad942e35 | 234 | total_freq = clamp_freq(base_freq + corr_freq * (1.0e6 - base_freq)); |
fc235a3f ML |
235 | |
236 | /* Set the new frequency (the actual frequency returned by the call may be | |
237 | slightly different from the requested frequency due to rounding) */ | |
238 | total_freq = (*drv_set_freq)(total_freq); | |
239 | ||
240 | /* Compute the new slewing frequency, it's relative to the real frequency to | |
241 | make the calculation in offset_convert() cheaper */ | |
242 | old_slew_freq = slew_freq; | |
243 | slew_freq = (total_freq - base_freq) / (1.0e6 - total_freq); | |
244 | ||
245 | /* Compute the dispersion introduced by changing frequency and add it | |
246 | to all statistics held at higher levels in the system */ | |
247 | slew_error = fabs((old_slew_freq - slew_freq) * max_freq_change_delay); | |
e8bb95ba ML |
248 | if (slew_error >= MIN_OFFSET_CORRECTION) |
249 | lcl_InvokeDispersionNotifyHandlers(slew_error); | |
fc235a3f ML |
250 | |
251 | /* Compute the duration of the slew and clamp it. If the slewing frequency | |
252 | is zero or has wrong sign (e.g. due to rounding in the frequency driver or | |
d6fdae5f ML |
253 | when base_freq is larger than max_freq, or fast slew is active), use the |
254 | maximum timeout and try again on the next update. */ | |
f88a712d ML |
255 | if (fabs(offset_register) < MIN_OFFSET_CORRECTION || |
256 | offset_register * slew_freq <= 0.0) { | |
af8e4a51 | 257 | duration = MAX_SLEW_DURATION; |
fc235a3f ML |
258 | } else { |
259 | duration = offset_register / slew_freq; | |
af8e4a51 ML |
260 | if (duration < MIN_SLEW_DURATION) |
261 | duration = MIN_SLEW_DURATION; | |
262 | else if (duration > MAX_SLEW_DURATION) | |
263 | duration = MAX_SLEW_DURATION; | |
fc235a3f ML |
264 | } |
265 | ||
266 | /* Restart timer for the next update */ | |
d0dfa1de | 267 | UTI_AddDoubleToTimespec(&now, duration, &end_of_slew); |
fc235a3f | 268 | slew_timeout_id = SCH_AddTimeout(&end_of_slew, handle_end_of_slew, NULL); |
fc235a3f | 269 | slew_start = now; |
2ed88c31 | 270 | slew_duration = duration; |
fc235a3f | 271 | |
2ed88c31 ML |
272 | DEBUG_LOG("slew offset=%e corr_rate=%e base_freq=%f total_freq=%f slew_freq=%e" |
273 | " duration=%f excess=%f slew_error=%e", | |
274 | offset_register, correction_rate, base_freq, total_freq, slew_freq, | |
275 | slew_duration, slew_excess_duration, slew_error); | |
fc235a3f ML |
276 | } |
277 | ||
278 | /* ================================================== */ | |
279 | ||
280 | static void | |
281 | handle_end_of_slew(void *anything) | |
282 | { | |
0076458e | 283 | slew_timeout_id = 0; |
fc235a3f ML |
284 | update_slew(); |
285 | } | |
286 | ||
287 | /* ================================================== */ | |
288 | ||
289 | static double | |
290 | read_frequency(void) | |
291 | { | |
292 | return base_freq; | |
293 | } | |
294 | ||
295 | /* ================================================== */ | |
296 | ||
297 | static double | |
298 | set_frequency(double freq_ppm) | |
299 | { | |
300 | base_freq = freq_ppm; | |
301 | update_slew(); | |
302 | ||
303 | return base_freq; | |
304 | } | |
305 | ||
306 | /* ================================================== */ | |
307 | ||
308 | static void | |
309 | accrue_offset(double offset, double corr_rate) | |
310 | { | |
311 | offset_register += offset; | |
312 | correction_rate = corr_rate; | |
313 | ||
314 | update_slew(); | |
315 | } | |
316 | ||
317 | /* ================================================== */ | |
318 | /* Determine the correction to generate the cooked time for given raw time */ | |
319 | ||
320 | static void | |
d0dfa1de | 321 | offset_convert(struct timespec *raw, |
fc235a3f ML |
322 | double *corr, double *err) |
323 | { | |
d6fdae5f | 324 | double duration, fastslew_corr, fastslew_err; |
fc235a3f | 325 | |
cfe706f0 | 326 | duration = UTI_DiffTimespecsToDouble(raw, &slew_start); |
fc235a3f | 327 | |
d6fdae5f ML |
328 | if (drv_get_offset_correction && fastslew_active) { |
329 | drv_get_offset_correction(raw, &fastslew_corr, &fastslew_err); | |
330 | if (fastslew_corr == 0.0 && fastslew_err == 0.0) | |
331 | fastslew_active = 0; | |
332 | } else { | |
333 | fastslew_corr = fastslew_err = 0.0; | |
334 | } | |
335 | ||
336 | *corr = slew_freq * duration + fastslew_corr - offset_register; | |
337 | ||
338 | if (err) { | |
339 | *err = fastslew_err; | |
340 | if (fabs(duration) <= max_freq_change_delay) | |
341 | *err += slew_error; | |
342 | } | |
fc235a3f ML |
343 | } |
344 | ||
cf3c7b3b ML |
345 | /* ================================================== */ |
346 | /* Positive means currently fast of true time, i.e. jump backwards */ | |
347 | ||
f6a9c5c1 | 348 | static int |
cf3c7b3b ML |
349 | apply_step_offset(double offset) |
350 | { | |
d0dfa1de ML |
351 | struct timespec old_time, new_time; |
352 | struct timeval new_time_tv; | |
cf3c7b3b ML |
353 | double err; |
354 | ||
355 | LCL_ReadRawTime(&old_time); | |
d0dfa1de ML |
356 | UTI_AddDoubleToTimespec(&old_time, -offset, &new_time); |
357 | UTI_TimespecToTimeval(&new_time, &new_time_tv); | |
cf3c7b3b | 358 | |
d0dfa1de | 359 | if (PRV_SetTime(&new_time_tv, NULL) < 0) { |
f282856c | 360 | DEBUG_LOG("settimeofday() failed"); |
f6a9c5c1 | 361 | return 0; |
cf3c7b3b ML |
362 | } |
363 | ||
364 | LCL_ReadRawTime(&old_time); | |
cfe706f0 | 365 | err = UTI_DiffTimespecsToDouble(&old_time, &new_time); |
cf3c7b3b ML |
366 | |
367 | lcl_InvokeDispersionNotifyHandlers(fabs(err)); | |
f6a9c5c1 ML |
368 | |
369 | return 1; | |
cf3c7b3b ML |
370 | } |
371 | ||
fc235a3f ML |
372 | /* ================================================== */ |
373 | ||
02cbe5e1 ML |
374 | static void |
375 | set_sync_status(int synchronised, double est_error, double max_error) | |
376 | { | |
377 | double offset; | |
378 | ||
379 | offset = fabs(offset_register); | |
380 | if (est_error < offset) | |
381 | est_error = offset; | |
382 | max_error += offset; | |
383 | ||
384 | if (drv_set_sync_status) | |
385 | drv_set_sync_status(synchronised, est_error, max_error); | |
386 | } | |
387 | ||
388 | /* ================================================== */ | |
389 | ||
fc235a3f ML |
390 | void |
391 | SYS_Generic_CompleteFreqDriver(double max_set_freq_ppm, double max_set_freq_delay, | |
392 | lcl_ReadFrequencyDriver sys_read_freq, | |
393 | lcl_SetFrequencyDriver sys_set_freq, | |
394 | lcl_ApplyStepOffsetDriver sys_apply_step_offset, | |
d6fdae5f ML |
395 | double min_fastslew_offset, double max_fastslew_rate, |
396 | lcl_AccrueOffsetDriver sys_accrue_offset, | |
397 | lcl_OffsetCorrectionDriver sys_get_offset_correction, | |
e14a03a1 ML |
398 | lcl_SetLeapDriver sys_set_leap, |
399 | lcl_SetSyncStatusDriver sys_set_sync_status) | |
fc235a3f ML |
400 | { |
401 | max_freq = max_set_freq_ppm; | |
402 | max_freq_change_delay = max_set_freq_delay * (1.0 + max_freq / 1.0e6); | |
403 | drv_read_freq = sys_read_freq; | |
404 | drv_set_freq = sys_set_freq; | |
d6fdae5f ML |
405 | drv_accrue_offset = sys_accrue_offset; |
406 | drv_get_offset_correction = sys_get_offset_correction; | |
02cbe5e1 | 407 | drv_set_sync_status = sys_set_sync_status; |
fc235a3f ML |
408 | |
409 | base_freq = (*drv_read_freq)(); | |
410 | slew_freq = 0.0; | |
411 | offset_register = 0.0; | |
2ed88c31 | 412 | slew_excess_duration = 0.0; |
fc235a3f | 413 | |
9cf78b97 ML |
414 | max_corr_freq = CNF_GetMaxSlewRate() / 1.0e6; |
415 | ||
d6fdae5f ML |
416 | fastslew_min_offset = min_fastslew_offset; |
417 | fastslew_max_rate = max_fastslew_rate / 1.0e6; | |
418 | fastslew_active = 0; | |
419 | ||
fc235a3f | 420 | lcl_RegisterSystemDrivers(read_frequency, set_frequency, |
cf3c7b3b ML |
421 | accrue_offset, sys_apply_step_offset ? |
422 | sys_apply_step_offset : apply_step_offset, | |
02cbe5e1 | 423 | offset_convert, sys_set_leap, set_sync_status); |
fc235a3f ML |
424 | |
425 | LCL_AddParameterChangeHandler(handle_step, NULL); | |
426 | } | |
427 | ||
428 | /* ================================================== */ | |
429 | ||
430 | void | |
431 | SYS_Generic_Finalise(void) | |
432 | { | |
d0dfa1de | 433 | struct timespec now; |
d6fdae5f | 434 | |
fc235a3f ML |
435 | /* Must *NOT* leave a slew running - clock could drift way off |
436 | if the daemon is not restarted */ | |
0076458e ML |
437 | |
438 | SCH_RemoveTimeout(slew_timeout_id); | |
439 | slew_timeout_id = 0; | |
fc235a3f | 440 | |
ad942e35 | 441 | (*drv_set_freq)(clamp_freq(base_freq)); |
d6fdae5f ML |
442 | |
443 | LCL_ReadRawTime(&now); | |
444 | stop_fastslew(&now); | |
5f6f265f ML |
445 | |
446 | LCL_RemoveParameterChangeHandler(handle_step, NULL); | |
fc235a3f ML |
447 | } |
448 | ||
449 | /* ================================================== */ |