-
Notifications
You must be signed in to change notification settings - Fork 2.9k
/
erl_time_sup.c
2453 lines (2078 loc) · 66.9 KB
/
erl_time_sup.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
/*
* %CopyrightBegin%
*
* Copyright Ericsson AB 1999-2015. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* %CopyrightEnd%
*/
/*
* Support routines for the time
*/
/* #define ERTS_TIME_CORRECTION_PRINT */
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include "sys.h"
#include "erl_vm.h"
#include "global.h"
#define ERTS_WANT_TIMER_WHEEL_API
#include "erl_time.h"
#include "erl_driver.h"
#include "erl_nif.h"
static erts_smp_mtx_t erts_timeofday_mtx;
static erts_smp_mtx_t erts_get_time_mtx;
static SysTimes t_start; /* Used in elapsed_time_both */
static ErtsMonotonicTime prev_wall_clock_elapsed; /* Used in wall_clock_elapsed_time_both */
static ErtsMonotonicTime previous_now; /* Used in get_now */
static ErtsMonitor *time_offset_monitors = NULL;
static Uint no_time_offset_monitors = 0;
#ifdef DEBUG
static int time_sup_initialized = 0;
#endif
#define ERTS_MONOTONIC_TIME_KILO \
((ErtsMonotonicTime) 1000)
#define ERTS_MONOTONIC_TIME_MEGA \
(ERTS_MONOTONIC_TIME_KILO*ERTS_MONOTONIC_TIME_KILO)
#define ERTS_MONOTONIC_TIME_GIGA \
(ERTS_MONOTONIC_TIME_MEGA*ERTS_MONOTONIC_TIME_KILO)
#define ERTS_MONOTONIC_TIME_TERA \
(ERTS_MONOTONIC_TIME_GIGA*ERTS_MONOTONIC_TIME_KILO)
static void init_time_napi(void);
static void
schedule_send_time_offset_changed_notifications(ErtsMonotonicTime new_offset);
struct time_sup_read_only__ {
ErtsMonotonicTime (*get_time)(void);
int correction;
ErtsTimeWarpMode warp_mode;
#ifdef ERTS_HAVE_OS_MONOTONIC_TIME_SUPPORT
ErtsMonotonicTime moffset;
int os_corrected_monotonic_time;
int os_monotonic_time_disable;
char *os_monotonic_time_func;
char *os_monotonic_time_clock_id;
int os_monotonic_time_locked;
Uint64 os_monotonic_time_resolution;
Uint64 os_monotonic_time_extended;
#endif
char *os_system_time_func;
char *os_system_time_clock_id;
int os_system_time_locked;
Uint64 os_system_time_resolution;
Uint64 os_system_time_extended;
struct {
ErtsMonotonicTime large_diff;
ErtsMonotonicTime small_diff;
} adj;
struct {
ErtsMonotonicTime error;
ErtsMonotonicTime resolution;
int intervals;
int use_avg;
} drift_adj;
};
typedef struct {
ErtsMonotonicTime drift; /* Correction for os monotonic drift */
ErtsMonotonicTime error; /* Correction for error between system times */
} ErtsMonotonicCorrection;
typedef struct {
ErtsMonotonicTime erl_mtime;
ErtsMonotonicTime os_mtime;
ErtsMonotonicCorrection correction;
} ErtsMonotonicCorrectionInstance;
#define ERTS_MAX_DRIFT_INTERVALS 50
typedef struct {
struct {
struct {
ErtsMonotonicTime sys;
ErtsMonotonicTime mon;
} diff;
struct {
ErtsMonotonicTime sys;
ErtsMonotonicTime mon;
} time;
} intervals[ERTS_MAX_DRIFT_INTERVALS];
struct {
ErtsMonotonicTime sys;
ErtsMonotonicTime mon;
} acc;
int ix;
int dirty_counter;
} ErtsMonotonicDriftData;
typedef struct {
ErtsMonotonicCorrectionInstance prev;
ErtsMonotonicCorrectionInstance curr;
} ErtsMonotonicCorrectionInstances;
typedef struct {
ErtsMonotonicCorrectionInstances insts;
ErtsMonotonicDriftData drift;
ErtsMonotonicTime last_check;
int short_check_interval;
} ErtsMonotonicCorrectionData;
struct time_sup_infrequently_changed__ {
#ifdef ERTS_HAVE_OS_MONOTONIC_TIME_SUPPORT
struct {
erts_smp_rwmtx_t rwmtx;
ErtsTWheelTimer timer;
ErtsMonotonicCorrectionData cdata;
} parmon;
ErtsMonotonicTime minit;
#endif
ErtsSystemTime sinit;
ErtsMonotonicTime not_corrected_moffset;
erts_smp_atomic64_t offset;
ErtsMonotonicTime shadow_offset;
erts_smp_atomic32_t preliminary_offset;
};
struct time_sup_frequently_changed__ {
ErtsMonotonicTime last_not_corrected_time;
};
static struct {
union {
struct time_sup_read_only__ o;
char align__[ERTS_ALC_CACHE_LINE_ALIGN_SIZE(sizeof(struct time_sup_read_only__))];
} r;
union {
struct time_sup_infrequently_changed__ c;
char align__[ERTS_ALC_CACHE_LINE_ALIGN_SIZE(sizeof(struct time_sup_infrequently_changed__))];
} inf;
union {
struct time_sup_frequently_changed__ c;
char align__[ERTS_ALC_CACHE_LINE_ALIGN_SIZE(sizeof(struct time_sup_frequently_changed__))];
} f;
} time_sup erts_align_attribute(ERTS_CACHE_LINE_SIZE);
ErtsTimeSupData erts_time_sup__ erts_align_attribute(ERTS_CACHE_LINE_SIZE);
/*
* erts_get_approx_time() returns an *approximate* time
* in seconds. NOTE that this time may jump backwards!!!
*/
erts_approx_time_t
erts_get_approx_time(void)
{
ErtsSystemTime stime = erts_os_system_time();
return (erts_approx_time_t) ERTS_MONOTONIC_TO_SEC(stime);
}
static ERTS_INLINE void
init_time_offset(ErtsMonotonicTime offset)
{
erts_smp_atomic64_init_nob(&time_sup.inf.c.offset, (erts_aint64_t) offset);
}
static ERTS_INLINE void
set_time_offset(ErtsMonotonicTime offset)
{
erts_smp_atomic64_set_relb(&time_sup.inf.c.offset, (erts_aint64_t) offset);
}
static ERTS_INLINE ErtsMonotonicTime
get_time_offset(void)
{
return (ErtsMonotonicTime) erts_smp_atomic64_read_acqb(&time_sup.inf.c.offset);
}
static ERTS_INLINE void
update_last_mtime(ErtsSchedulerData *esdp, ErtsMonotonicTime mtime)
{
if (!esdp)
esdp = erts_get_scheduler_data();
if (esdp) {
ASSERT(mtime >= esdp->last_monotonic_time);
esdp->last_monotonic_time = mtime;
esdp->check_time_reds = 0;
}
}
#ifdef ERTS_HAVE_OS_MONOTONIC_TIME_SUPPORT
/*
* Time correction adjustments made due to
* error between Erlang system time and OS
* system time:
* - Large adjustment ~1%
* - Small adjustment ~0.05%
*/
#define ERTS_TCORR_ERR_UNIT 2048
#define ERTS_TCORR_ERR_LARGE_ADJ 20
#define ERTS_TCORR_ERR_SMALL_ADJ 1
#define ERTS_INIT_SHORT_INTERVAL_COUNTER 10
#define ERTS_LONG_TIME_CORRECTION_CHECK ERTS_SEC_TO_MONOTONIC(60)
#define ERTS_SHORT_TIME_CORRECTION_CHECK ERTS_SEC_TO_MONOTONIC(15)
#define ERTS_TIME_DRIFT_MAX_ADJ_DIFF ERTS_USEC_TO_MONOTONIC(50)
#define ERTS_TIME_DRIFT_MIN_ADJ_DIFF ERTS_USEC_TO_MONOTONIC(5)
/*
* Maximum drift of the OS monotonic clock expected.
*
* We use 1 milli second per second. If the monotonic
* clock drifts more than this we will fail to adjust for
* drift, and error correction will kick in instead.
* If it is larger than this, one could argue that the
* primitive is to poor to be used...
*/
#define ERTS_MAX_MONOTONIC_DRIFT ERTS_MSEC_TO_MONOTONIC(1)
/*
* We assume that precision is 32 times worse than the
* resolution. This is a wild guess, but there are no
* practical way to determine actual precision.
*/
#define ERTS_ASSUMED_PRECISION_DROP 32
#define ERTS_MIN_MONOTONIC_DRIFT_MEASUREMENT \
(ERTS_SHORT_TIME_CORRECTION_CHECK - 2*ERTS_MAX_MONOTONIC_DRIFT)
static ERTS_INLINE ErtsMonotonicTime
calc_corrected_erl_mtime(ErtsMonotonicTime os_mtime,
ErtsMonotonicCorrectionInstance *cip,
ErtsMonotonicTime *os_mdiff_p,
int os_drift_corrected)
{
ErtsMonotonicTime erl_mtime, diff = os_mtime - cip->os_mtime;
ERTS_TIME_ASSERT(diff >= 0);
if (!os_drift_corrected)
diff += (cip->correction.drift*diff)/ERTS_MONOTONIC_TIME_UNIT;
erl_mtime = cip->erl_mtime;
erl_mtime += diff;
erl_mtime += cip->correction.error*(diff/ERTS_TCORR_ERR_UNIT);
if (os_mdiff_p)
*os_mdiff_p = diff;
return erl_mtime;
}
static ERTS_INLINE ErtsMonotonicTime
read_corrected_time(int os_drift_corrected)
{
ErtsMonotonicTime os_mtime;
ErtsMonotonicCorrectionInstance ci;
erts_smp_rwmtx_rlock(&time_sup.inf.c.parmon.rwmtx);
os_mtime = erts_os_monotonic_time();
if (os_mtime >= time_sup.inf.c.parmon.cdata.insts.curr.os_mtime)
ci = time_sup.inf.c.parmon.cdata.insts.curr;
else {
if (os_mtime < time_sup.inf.c.parmon.cdata.insts.prev.os_mtime)
erl_exit(ERTS_ABORT_EXIT,
"OS monotonic time stepped backwards\n");
ci = time_sup.inf.c.parmon.cdata.insts.prev;
}
erts_smp_rwmtx_runlock(&time_sup.inf.c.parmon.rwmtx);
return calc_corrected_erl_mtime(os_mtime, &ci, NULL,
os_drift_corrected);
}
static ErtsMonotonicTime get_os_drift_corrected_time(void)
{
return read_corrected_time(!0);
}
static ErtsMonotonicTime get_corrected_time(void)
{
return read_corrected_time(0);
}
#ifdef ERTS_TIME_CORRECTION_PRINT
static ERTS_INLINE void
print_correction(int change,
ErtsMonotonicTime sdiff,
ErtsMonotonicTime old_ecorr,
ErtsMonotonicTime old_dcorr,
ErtsMonotonicTime new_ecorr,
ErtsMonotonicTime new_dcorr,
Uint tmo)
{
ErtsMonotonicTime usec_sdiff;
if (sdiff < 0)
usec_sdiff = -1*ERTS_MONOTONIC_TO_USEC(-1*sdiff);
else
usec_sdiff = ERTS_MONOTONIC_TO_USEC(sdiff);
if (!change)
erts_fprintf(stderr,
"sdiff = %b64d usec : [ec=%b64d ppm, dc=%b64d ppb] : "
"tmo = %bpu msec\r\n",
usec_sdiff,
(1000000*old_ecorr) / ERTS_TCORR_ERR_UNIT,
(1000000000*old_dcorr) / ERTS_MONOTONIC_TIME_UNIT,
tmo);
else
erts_fprintf(stderr,
"sdiff = %b64d usec : [ec=%b64d ppm, dc=%b64d ppb] "
"-> [ec=%b64d ppm, dc=%b64d ppb] : tmo = %bpu msec\r\n",
usec_sdiff,
(1000000*old_ecorr) / ERTS_TCORR_ERR_UNIT,
(1000000000*old_dcorr) / ERTS_MONOTONIC_TIME_UNIT,
(1000000*new_ecorr) / ERTS_TCORR_ERR_UNIT,
(1000000000*new_dcorr) / ERTS_MONOTONIC_TIME_UNIT,
tmo);
}
#endif
static ERTS_INLINE ErtsMonotonicTime
get_timeout_pos(ErtsMonotonicTime now, ErtsMonotonicTime tmo)
{
ErtsMonotonicTime tpos;
tpos = ERTS_MONOTONIC_TO_CLKTCKS(now - 1);
tpos += ERTS_MSEC_TO_CLKTCKS(tmo);
tpos += 1;
return tpos;
}
static void
check_time_correction(void *vesdp)
{
int init_drift_adj = !vesdp;
ErtsSchedulerData *esdp = (ErtsSchedulerData *) vesdp;
ErtsMonotonicCorrection new_correction;
ErtsMonotonicCorrectionInstance ci;
ErtsMonotonicTime mdiff, sdiff, os_mtime, erl_mtime, os_stime,
erl_stime, time_offset, timeout_pos;
Uint timeout;
int os_drift_corrected = time_sup.r.o.os_corrected_monotonic_time;
int set_new_correction = 0, begin_short_intervals = 0;
erts_smp_rwmtx_rlock(&time_sup.inf.c.parmon.rwmtx);
erts_os_times(&os_mtime, &os_stime);
ci = time_sup.inf.c.parmon.cdata.insts.curr;
erts_smp_rwmtx_runlock(&time_sup.inf.c.parmon.rwmtx);
if (os_mtime < ci.os_mtime)
erl_exit(ERTS_ABORT_EXIT,
"OS monotonic time stepped backwards\n");
erl_mtime = calc_corrected_erl_mtime(os_mtime, &ci, &mdiff,
os_drift_corrected);
time_offset = get_time_offset();
erl_stime = erl_mtime + time_offset;
sdiff = erl_stime - os_stime;
if (time_sup.inf.c.shadow_offset) {
ERTS_TIME_ASSERT(time_sup.r.o.warp_mode == ERTS_SINGLE_TIME_WARP_MODE);
if (erts_smp_atomic32_read_nob(&time_sup.inf.c.preliminary_offset))
sdiff += time_sup.inf.c.shadow_offset;
else
time_sup.inf.c.shadow_offset = 0;
}
new_correction = ci.correction;
if (time_sup.r.o.warp_mode == ERTS_MULTI_TIME_WARP_MODE
&& (sdiff < -2*time_sup.r.o.adj.small_diff
|| 2*time_sup.r.o.adj.small_diff < sdiff)) {
/* System time diff exeeded limits; change time offset... */
time_offset -= sdiff;
sdiff = 0;
set_time_offset(time_offset);
schedule_send_time_offset_changed_notifications(time_offset);
begin_short_intervals = 1;
if (ci.correction.error != 0) {
set_new_correction = 1;
new_correction.error = 0;
}
}
else if ((time_sup.r.o.warp_mode == ERTS_SINGLE_TIME_WARP_MODE
&& erts_smp_atomic32_read_nob(&time_sup.inf.c.preliminary_offset))
&& (sdiff < -2*time_sup.r.o.adj.small_diff
|| 2*time_sup.r.o.adj.small_diff < sdiff)) {
/*
* System time diff exeeded limits; change shadow offset
* and let OS system time leap away from Erlang system
* time.
*/
time_sup.inf.c.shadow_offset -= sdiff;
sdiff = 0;
begin_short_intervals = 1;
if (ci.correction.error != 0) {
set_new_correction = 1;
new_correction.error = 0;
}
}
else if (ci.correction.error == 0) {
if (sdiff < -time_sup.r.o.adj.small_diff) {
set_new_correction = 1;
if (sdiff < -time_sup.r.o.adj.large_diff)
new_correction.error = ERTS_TCORR_ERR_LARGE_ADJ;
else
new_correction.error = ERTS_TCORR_ERR_SMALL_ADJ;
}
else if (sdiff > time_sup.r.o.adj.small_diff) {
set_new_correction = 1;
if (sdiff > time_sup.r.o.adj.large_diff)
new_correction.error = -ERTS_TCORR_ERR_LARGE_ADJ;
else
new_correction.error = -ERTS_TCORR_ERR_SMALL_ADJ;
}
}
else if (ci.correction.error > 0) {
if (sdiff < 0) {
if (ci.correction.error != ERTS_TCORR_ERR_LARGE_ADJ
&& sdiff < -time_sup.r.o.adj.large_diff) {
new_correction.error = ERTS_TCORR_ERR_LARGE_ADJ;
set_new_correction = 1;
}
}
else if (sdiff > time_sup.r.o.adj.small_diff) {
set_new_correction = 1;
if (sdiff > time_sup.r.o.adj.large_diff)
new_correction.error = -ERTS_TCORR_ERR_LARGE_ADJ;
else
new_correction.error = -ERTS_TCORR_ERR_SMALL_ADJ;
}
else {
set_new_correction = 1;
new_correction.error = 0;
}
}
else /* if (ci.correction.error < 0) */ {
if (0 < sdiff) {
if (ci.correction.error != -ERTS_TCORR_ERR_LARGE_ADJ
&& time_sup.r.o.adj.large_diff < sdiff) {
new_correction.error = -ERTS_TCORR_ERR_LARGE_ADJ;
set_new_correction = 1;
}
}
else if (sdiff < -time_sup.r.o.adj.small_diff) {
set_new_correction = 1;
if (sdiff < -time_sup.r.o.adj.large_diff)
new_correction.error = ERTS_TCORR_ERR_LARGE_ADJ;
else
new_correction.error = ERTS_TCORR_ERR_SMALL_ADJ;
}
else {
set_new_correction = 1;
new_correction.error = 0;
}
}
if (!os_drift_corrected) {
ErtsMonotonicDriftData *ddp = &time_sup.inf.c.parmon.cdata.drift;
int ix = ddp->ix;
ErtsMonotonicTime mtime_diff, old_os_mtime;
old_os_mtime = ddp->intervals[ix].time.mon;
mtime_diff = os_mtime - old_os_mtime;
if ((mtime_diff >= ERTS_MIN_MONOTONIC_DRIFT_MEASUREMENT)
| init_drift_adj) {
ErtsMonotonicTime drift_adj, drift_adj_diff, old_os_stime,
smtime_diff, stime_diff, mtime_acc, stime_acc,
avg_drift_adj, max_drift;
old_os_stime = ddp->intervals[ix].time.sys;
mtime_acc = ddp->acc.mon;
stime_acc = ddp->acc.sys;
avg_drift_adj = (((stime_acc - mtime_acc)
* ERTS_MONOTONIC_TIME_UNIT)
/ mtime_acc);
mtime_diff = os_mtime - old_os_mtime;
stime_diff = os_stime - old_os_stime;
smtime_diff = stime_diff - mtime_diff;
ix++;
if (ix >= time_sup.r.o.drift_adj.intervals)
ix = 0;
mtime_acc -= ddp->intervals[ix].diff.mon;
mtime_acc += mtime_diff;
stime_acc -= ddp->intervals[ix].diff.sys;
stime_acc += stime_diff;
ddp->intervals[ix].diff.mon = mtime_diff;
ddp->intervals[ix].diff.sys = stime_diff;
ddp->intervals[ix].time.mon = os_mtime;
ddp->intervals[ix].time.sys = os_stime;
ddp->ix = ix;
ddp->acc.mon = mtime_acc;
ddp->acc.sys = stime_acc;
max_drift = ERTS_MAX_MONOTONIC_DRIFT;
max_drift *= ERTS_MONOTONIC_TO_SEC(mtime_diff);
if (smtime_diff > time_sup.r.o.drift_adj.error + max_drift
|| smtime_diff < -1*time_sup.r.o.drift_adj.error - max_drift) {
dirty_intervals:
/*
* We had a leap in system time. Mark array as
* dirty to ensure that dirty values are rotated
* out before we use it again...
*/
ddp->dirty_counter = time_sup.r.o.drift_adj.intervals;
begin_short_intervals = 1;
}
else if (ddp->dirty_counter > 0) {
if (init_drift_adj) {
new_correction.drift = ((smtime_diff
* ERTS_MONOTONIC_TIME_UNIT)
/ mtime_diff);
set_new_correction = 1;
}
ddp->dirty_counter--;
}
else {
if (ddp->dirty_counter == 0) {
/* Force set new drift correction... */
set_new_correction = 1;
ddp->dirty_counter--;
}
if (time_sup.r.o.drift_adj.use_avg)
drift_adj = (((stime_acc - mtime_acc)
* ERTS_MONOTONIC_TIME_UNIT)
/ mtime_acc);
else
drift_adj = ((smtime_diff
* ERTS_MONOTONIC_TIME_UNIT)
/ mtime_diff);
drift_adj_diff = avg_drift_adj - drift_adj;
if (drift_adj_diff < -ERTS_TIME_DRIFT_MAX_ADJ_DIFF
|| ERTS_TIME_DRIFT_MAX_ADJ_DIFF < drift_adj_diff)
goto dirty_intervals;
drift_adj_diff = drift_adj - new_correction.drift;
if (drift_adj_diff) {
if (drift_adj_diff > ERTS_TIME_DRIFT_MAX_ADJ_DIFF)
drift_adj_diff = ERTS_TIME_DRIFT_MAX_ADJ_DIFF;
else if (drift_adj_diff < -ERTS_TIME_DRIFT_MAX_ADJ_DIFF)
drift_adj_diff = -ERTS_TIME_DRIFT_MAX_ADJ_DIFF;
new_correction.drift += drift_adj_diff;
if (drift_adj_diff < -ERTS_TIME_DRIFT_MIN_ADJ_DIFF
|| ERTS_TIME_DRIFT_MIN_ADJ_DIFF < drift_adj_diff) {
set_new_correction = 1;
}
}
}
}
}
begin_short_intervals |= set_new_correction;
if (begin_short_intervals) {
time_sup.inf.c.parmon.cdata.short_check_interval
= ERTS_INIT_SHORT_INTERVAL_COUNTER;
}
else if ((os_mtime - time_sup.inf.c.parmon.cdata.last_check
>= ERTS_SHORT_TIME_CORRECTION_CHECK - ERTS_MONOTONIC_TIME_UNIT)
&& time_sup.inf.c.parmon.cdata.short_check_interval > 0) {
time_sup.inf.c.parmon.cdata.short_check_interval--;
}
time_sup.inf.c.parmon.cdata.last_check = os_mtime;
if (new_correction.error == 0)
timeout = ERTS_MONOTONIC_TO_MSEC(ERTS_LONG_TIME_CORRECTION_CHECK);
else {
ErtsMonotonicTime ecorr = new_correction.error;
ErtsMonotonicTime abs_sdiff;
abs_sdiff = (sdiff < 0) ? -1*sdiff : sdiff;
if (ecorr < 0)
ecorr = -1*ecorr;
if (abs_sdiff > ecorr*(ERTS_LONG_TIME_CORRECTION_CHECK/ERTS_TCORR_ERR_UNIT))
timeout = ERTS_MONOTONIC_TO_MSEC(ERTS_LONG_TIME_CORRECTION_CHECK);
else {
timeout = ERTS_MONOTONIC_TO_MSEC((ERTS_TCORR_ERR_UNIT*abs_sdiff)/ecorr);
if (timeout < 10)
timeout = 10;
}
}
if (timeout > ERTS_MONOTONIC_TO_MSEC(ERTS_SHORT_TIME_CORRECTION_CHECK)
&& (time_sup.inf.c.parmon.cdata.short_check_interval
|| time_sup.inf.c.parmon.cdata.drift.dirty_counter >= 0)) {
timeout = ERTS_MONOTONIC_TO_MSEC(ERTS_SHORT_TIME_CORRECTION_CHECK);
}
timeout_pos = get_timeout_pos(erl_mtime, timeout);
#ifdef ERTS_TIME_CORRECTION_PRINT
print_correction(set_new_correction,
sdiff,
ci.correction.error,
ci.correction.drift,
new_correction.error,
new_correction.drift,
timeout);
#endif
if (set_new_correction) {
erts_smp_rwmtx_rwlock(&time_sup.inf.c.parmon.rwmtx);
os_mtime = erts_os_monotonic_time();
/* Save previous correction instance */
time_sup.inf.c.parmon.cdata.insts.prev = ci;
/*
* Current correction instance begin when
* OS monotonic time has increased two units.
*/
os_mtime += 2;
/*
* Erlang monotonic time corresponding to
* next OS monotonic time using previous
* correction.
*/
erl_mtime = calc_corrected_erl_mtime(os_mtime, &ci, NULL,
os_drift_corrected);
/*
* Save new current correction instance.
*/
time_sup.inf.c.parmon.cdata.insts.curr.erl_mtime = erl_mtime;
time_sup.inf.c.parmon.cdata.insts.curr.os_mtime = os_mtime;
time_sup.inf.c.parmon.cdata.insts.curr.correction = new_correction;
erts_smp_rwmtx_rwunlock(&time_sup.inf.c.parmon.rwmtx);
}
if (!esdp)
esdp = erts_get_scheduler_data();
erts_twheel_set_timer(esdp->timer_wheel,
&time_sup.inf.c.parmon.timer,
check_time_correction,
NULL,
(void *) esdp,
timeout_pos);
}
static ErtsMonotonicTime get_os_corrected_time(void)
{
ASSERT(time_sup.r.o.warp_mode == ERTS_MULTI_TIME_WARP_MODE);
return erts_os_monotonic_time() + time_sup.r.o.moffset;
}
static void
check_time_offset(void *vesdp)
{
ErtsSchedulerData *esdp = (ErtsSchedulerData *) vesdp;
ErtsMonotonicTime sdiff, os_mtime, erl_mtime, os_stime,
erl_stime, time_offset, timeout, timeout_pos;
ASSERT(time_sup.r.o.warp_mode == ERTS_MULTI_TIME_WARP_MODE);
erts_os_times(&os_mtime, &os_stime);
erl_mtime = os_mtime + time_sup.r.o.moffset;
time_offset = get_time_offset();
erl_stime = erl_mtime + time_offset;
sdiff = erl_stime - os_stime;
if ((sdiff < -2*time_sup.r.o.adj.small_diff
|| 2*time_sup.r.o.adj.small_diff < sdiff)) {
/* System time diff exeeded limits; change time offset... */
#ifdef ERTS_TIME_CORRECTION_PRINT
erts_fprintf(stderr, "sdiff = %b64d nsec -> 0 nsec\n",
ERTS_MONOTONIC_TO_NSEC(sdiff));
#endif
time_offset -= sdiff;
sdiff = 0;
set_time_offset(time_offset);
schedule_send_time_offset_changed_notifications(time_offset);
}
#ifdef ERTS_TIME_CORRECTION_PRINT
else erts_fprintf(stderr, "sdiff = %b64d nsec\n",
ERTS_MONOTONIC_TO_NSEC(sdiff));
#endif
timeout = ERTS_MONOTONIC_TO_MSEC(ERTS_LONG_TIME_CORRECTION_CHECK);
timeout_pos = get_timeout_pos(erl_mtime, timeout);
erts_twheel_set_timer(esdp->timer_wheel,
&time_sup.inf.c.parmon.timer,
check_time_offset,
NULL,
vesdp,
timeout_pos);
}
static void
init_check_time_correction(void *vesdp)
{
ErtsMonotonicDriftData *ddp;
ErtsMonotonicTime old_mtime, old_stime, mtime, stime, mtime_diff,
stime_diff, smtime_diff, max_drift;
int ix;
ddp = &time_sup.inf.c.parmon.cdata.drift;
ix = ddp->ix;
old_mtime = ddp->intervals[0].time.mon;
old_stime = ddp->intervals[0].time.sys;
erts_os_times(&mtime, &stime);
mtime_diff = mtime - old_mtime;
stime_diff = stime - old_stime;
smtime_diff = stime_diff - mtime_diff;
max_drift = ERTS_MAX_MONOTONIC_DRIFT;
max_drift *= ERTS_MONOTONIC_TO_SEC(mtime_diff);
if (smtime_diff > time_sup.r.o.drift_adj.error + max_drift
|| smtime_diff < -1*time_sup.r.o.drift_adj.error - max_drift) {
/* Had a system time leap... pretend no drift... */
stime_diff = mtime_diff;
}
/*
* We use old time values in order to trigger
* a drift adjustment, and repeat this interval
* in all slots...
*/
for (ix = 0; ix < time_sup.r.o.drift_adj.intervals; ix++) {
ddp->intervals[ix].diff.mon = mtime_diff;
ddp->intervals[ix].diff.sys = stime_diff;
ddp->intervals[ix].time.mon = old_mtime;
ddp->intervals[ix].time.sys = old_stime;
}
ddp->acc.sys = stime_diff*time_sup.r.o.drift_adj.intervals;
ddp->acc.mon = mtime_diff*time_sup.r.o.drift_adj.intervals;
ddp->ix = 0;
ddp->dirty_counter = time_sup.r.o.drift_adj.intervals;
check_time_correction(vesdp);
}
static ErtsMonotonicTime
finalize_corrected_time_offset(ErtsSystemTime *stimep)
{
ErtsMonotonicTime os_mtime;
ErtsMonotonicCorrectionInstance ci;
int os_drift_corrected = time_sup.r.o.os_corrected_monotonic_time;
erts_smp_rwmtx_rlock(&time_sup.inf.c.parmon.rwmtx);
erts_os_times(&os_mtime, stimep);
ci = time_sup.inf.c.parmon.cdata.insts.curr;
erts_smp_rwmtx_runlock(&time_sup.inf.c.parmon.rwmtx);
if (os_mtime < ci.os_mtime)
erl_exit(ERTS_ABORT_EXIT,
"OS monotonic time stepped backwards\n");
return calc_corrected_erl_mtime(os_mtime, &ci, NULL,
os_drift_corrected);
}
static void
late_init_time_correction(ErtsSchedulerData *esdp)
{
int quick_init_drift_adj;
void (*check_func)(void *);
ErtsMonotonicTime timeout, timeout_pos;
quick_init_drift_adj =
ERTS_MONOTONIC_TO_USEC(time_sup.r.o.drift_adj.error) == 0;
if (quick_init_drift_adj)
timeout = ERTS_MONOTONIC_TO_MSEC(ERTS_SHORT_TIME_CORRECTION_CHECK/10);
else
timeout = ERTS_MONOTONIC_TO_MSEC(ERTS_SHORT_TIME_CORRECTION_CHECK);
if (!time_sup.r.o.os_corrected_monotonic_time)
check_func = init_check_time_correction;
else if (time_sup.r.o.get_time == get_os_corrected_time) {
quick_init_drift_adj = 0;
check_func = check_time_offset;
}
else
check_func = check_time_correction;
timeout_pos = get_timeout_pos(erts_get_monotonic_time(esdp),
timeout);
erts_twheel_init_timer(&time_sup.inf.c.parmon.timer);
erts_twheel_set_timer(esdp->timer_wheel,
&time_sup.inf.c.parmon.timer,
check_func,
NULL,
(quick_init_drift_adj
? NULL
: esdp),
timeout_pos);
}
#endif /* ERTS_HAVE_OS_MONOTONIC_TIME_SUPPORT */
static ErtsMonotonicTime get_not_corrected_time(void)
{
ErtsMonotonicTime stime, mtime;
erts_smp_mtx_lock(&erts_get_time_mtx);
stime = erts_os_system_time();
mtime = stime - time_sup.inf.c.not_corrected_moffset;
if (mtime >= time_sup.f.c.last_not_corrected_time)
time_sup.f.c.last_not_corrected_time = mtime;
else {
mtime = time_sup.f.c.last_not_corrected_time;
if (time_sup.r.o.warp_mode == ERTS_MULTI_TIME_WARP_MODE) {
ErtsMonotonicTime new_offset = stime - mtime;
new_offset = ERTS_MONOTONIC_TO_USEC(new_offset);
new_offset = ERTS_USEC_TO_MONOTONIC(new_offset);
if (time_sup.inf.c.not_corrected_moffset != new_offset) {
time_sup.inf.c.not_corrected_moffset = new_offset;
set_time_offset(new_offset);
schedule_send_time_offset_changed_notifications(new_offset);
}
}
}
ASSERT(stime == mtime + time_sup.inf.c.not_corrected_moffset);
erts_smp_mtx_unlock(&erts_get_time_mtx);
return mtime;
}
int erts_check_time_adj_support(int time_correction,
ErtsTimeWarpMode time_warp_mode)
{
if (!time_correction)
return 1;
/* User wants time correction */
#ifdef ERTS_HAVE_OS_MONOTONIC_TIME_SUPPORT
return !time_sup.r.o.os_monotonic_time_disable;
#else
return 0;
#endif
}
int
erts_has_time_correction(void)
{
return time_sup.r.o.correction;
}
void erts_init_sys_time_sup(void)
{
ErtsSysInitTimeResult sys_init_time_res
= ERTS_SYS_INIT_TIME_RESULT_INITER;
sys_init_time(&sys_init_time_res);
erts_time_sup__.r.o.monotonic_time_unit
= sys_init_time_res.os_monotonic_time_unit;
#ifndef SYS_CLOCK_RESOLUTION
erts_time_sup__.r.o.clktck_resolution
= sys_init_time_res.sys_clock_resolution;
erts_time_sup__.r.o.clktck_resolution *= 1000;
#endif
#ifdef ERTS_HAVE_OS_MONOTONIC_TIME_SUPPORT
time_sup.r.o.os_monotonic_time_disable
= !sys_init_time_res.have_os_monotonic_time;
time_sup.r.o.os_corrected_monotonic_time =
sys_init_time_res.have_corrected_os_monotonic_time;
time_sup.r.o.os_monotonic_time_func
= sys_init_time_res.os_monotonic_time_info.func;
time_sup.r.o.os_monotonic_time_clock_id
= sys_init_time_res.os_monotonic_time_info.clock_id;
time_sup.r.o.os_monotonic_time_locked
= sys_init_time_res.os_monotonic_time_info.locked_use;
time_sup.r.o.os_monotonic_time_resolution
= sys_init_time_res.os_monotonic_time_info.resolution;
time_sup.r.o.os_monotonic_time_extended
= sys_init_time_res.os_monotonic_time_info.extended;
#endif
time_sup.r.o.os_system_time_func
= sys_init_time_res.os_system_time_info.func;
time_sup.r.o.os_system_time_clock_id
= sys_init_time_res.os_system_time_info.clock_id;
time_sup.r.o.os_system_time_locked
= sys_init_time_res.os_system_time_info.locked_use;
time_sup.r.o.os_system_time_resolution
= sys_init_time_res.os_system_time_info.resolution;
}
int
erts_init_time_sup(int time_correction, ErtsTimeWarpMode time_warp_mode)
{
ErtsMonotonicTime resolution, ilength, intervals, short_isecs;
#if !ERTS_COMPILE_TIME_MONOTONIC_TIME_UNIT
ErtsMonotonicTime abs_native_offset, native_offset;
#endif
init_time_napi();
erts_hl_timer_init();
ASSERT(ERTS_MONOTONIC_TIME_MIN < ERTS_MONOTONIC_TIME_MAX);
erts_smp_mtx_init(&erts_timeofday_mtx, "timeofday");
erts_smp_mtx_init(&erts_get_time_mtx, "get_time");
time_sup.r.o.correction = time_correction;
time_sup.r.o.warp_mode = time_warp_mode;
if (time_warp_mode == ERTS_SINGLE_TIME_WARP_MODE)
erts_smp_atomic32_init_nob(&time_sup.inf.c.preliminary_offset, 1);
else
erts_smp_atomic32_init_nob(&time_sup.inf.c.preliminary_offset, 0);
time_sup.inf.c.shadow_offset = 0;
#if !ERTS_COMPILE_TIME_MONOTONIC_TIME_UNIT
/*
* NOTE! erts_time_sup__.r.o.start *need* to be a multiple
* of ERTS_MONOTONIC_TIME_UNIT.
*/
#ifdef ARCH_32
erts_time_sup__.r.o.start = ((((ErtsMonotonicTime) 1) << 32)-1);
erts_time_sup__.r.o.start /= ERTS_MONOTONIC_TIME_UNIT;
erts_time_sup__.r.o.start *= ERTS_MONOTONIC_TIME_UNIT;
erts_time_sup__.r.o.start += ERTS_MONOTONIC_TIME_UNIT;
native_offset = erts_time_sup__.r.o.start - ERTS_MONOTONIC_BEGIN;
abs_native_offset = native_offset;
#else /* ARCH_64 */
if (ERTS_MONOTONIC_TIME_UNIT <= 10*1000*1000) {
erts_time_sup__.r.o.start = 0;
native_offset = -ERTS_MONOTONIC_BEGIN;
abs_native_offset = ERTS_MONOTONIC_BEGIN;
}
else {
erts_time_sup__.r.o.start = ((ErtsMonotonicTime) MIN_SMALL);
erts_time_sup__.r.o.start /= ERTS_MONOTONIC_TIME_UNIT;
erts_time_sup__.r.o.start *= ERTS_MONOTONIC_TIME_UNIT;
native_offset = erts_time_sup__.r.o.start - ERTS_MONOTONIC_BEGIN;
abs_native_offset = -1*native_offset;
}
#endif