| Re: [chrony-dev] [PATCH] macOS - support for ntp_adjtime() |
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- To: chrony-dev@xxxxxxxxxxxxxxxxxxxx
- Subject: Re: [chrony-dev] [PATCH] macOS - support for ntp_adjtime()
- From: Bryan Christianson <bryan@xxxxxxxxxxxxx>
- Date: Tue, 11 Jul 2017 11:53:35 +1200
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Hi Miroslov
There is a new release of macOS 10.13 out today but as yet no fix for the adjtime() issue.
> On 11/07/2017, at 2:49 AM, Miroslav Lichvar <mlichvar@xxxxxxxxxx> wrote:
>
> Is it really 5000 ppm on macOS 10.13? There is a testing program
> test/kernel/adjtime, which should print the maximum slew rate. You
> may need to modify it to try a larger offset than 1 second. On an
> older macOS it was 42000 ppm.
>
> I like that you reused the FreeBSD/NetBSD driver, but if adjtime()
> behaves differently, then maybe it would be better to duplicate the
> fast-slewing functionality in the macOS driver instead.
I ran the adjtime test on macOS 10.13. The skew results were surprising and appear to me to be the same as what you have on FreeBSD/NetBSD. Quite different from macOS 10.12 and earlier. It looks as though Apple have moved the FreeBSD implementation directly into their kernel (and made a signed/unsigned error at the same time).
I think we should stick with calling the netbsd driver from the macOS driver.
sierra-beta:chronycontrol bryan$ sysctl -a|grep kern.clock
kern.clockrate: { hz = 100, tick = 10000, tickadj = 2, profhz = 100, stathz = 100 }
From <sys/timex.h>
/*
* The following defines establish the performance envelope of the
* kernel discipline loop. Phase or frequency errors greater than
* NAXPHASE or MAXFREQ are clamped to these maxima. For update intervals
* less than MINSEC, the loop always operates in PLL mode; while, for
* update intervals greater than MAXSEC, the loop always operates in FLL
* mode. Between these two limits the operating mode is selected by the
* STA_FLL bit in the status word.
*/
#define MAXPHASE 500000000L /* max phase error (ns) */
#define MAXFREQ 500000L /* max freq error (ns/s) */
#define MINSEC 256 /* min FLL update interval (s) */
#define MAXSEC 2048 /* max PLL update interval (s) */
#define NANOSECOND 1000000000L /* nanoseconds in one second */
#define SCALE_PPM (65536 / 1000) /* crude ns/s to scaled PPM */
#define MAXTC 10 /* max time constant */
test/kernel/adjtime
range:
0 s : ok
-1 s : ok
1 s : ok
-2 s : ok
3 s : ok
-4 s : ok
7 s : ok
-8 s : ok
15 s : ok
-16 s : ok
31 s : ok
-32 s : ok
63 s : ok
-64 s : ok
127 s : ok
-128 s : ok
255 s : ok
-256 s : ok
511 s : ok
-512 s : ok
1023 s : ok
-1024 s : ok
2047 s : ok
-2048 s : ok
4095 s : ok
-4096 s : ok
8191 s : ok
-8192 s : ok
16383 s : ok
-16384 s : ok
32767 s : ok
-32768 s : ok
65535 s : ok
-65536 s : ok
131071 s : ok
-131072 s : ok
262143 s : ok
-262144 s : ok
524287 s : ok
-524288 s : ok
1048575 s : ok
-1048576 s : ok
2097151 s : ok
-2097152 s : ok
4194303 s : ok
-4194304 s : ok
8388607 s : ok
-8388608 s : ok
16777215 s : ok
-16777216 s : ok
33554431 s : ok
-33554432 s : ok
67108863 s : ok
-67108864 s : ok
134217727 s : ok
-134217728 s : ok
268435455 s : ok
-268435456 s : ok
536870911 s : ok
-536870912 s : ok
1073741823 s : ok
-1073741824 s : ok
2147483647 s : ok
-2147483648 s : ok
4294967295 s : ok
-4294967296 s : ok
8589934591 s : ok
-8589934592 s : ok
17179869183 s : ok
-17179869184 s : ok
34359738367 s : ok
-34359738368 s : ok
68719476735 s : ok
-68719476736 s : ok
137438953471 s : ok
-137438953472 s : ok
274877906943 s : ok
-274877906944 s : ok
549755813887 s : ok
-549755813888 s : ok
1099511627775 s : ok
-1099511627776 s : ok
2199023255551 s : ok
-2199023255552 s : ok
4398046511103 s : ok
-4398046511104 s : ok
8796093022207 s : ok
-8796093022208 s : ok
17592186044415 s : ok
-17592186044416 s : ok
35184372088831 s : ok
-35184372088832 s : ok
70368744177663 s : ok
-70368744177664 s : ok
140737488355327 s : ok
-140737488355328 s : ok
281474976710655 s : ok
-281474976710656 s : ok
562949953421311 s : ok
-562949953421312 s : ok
1125899906842623 s : ok
-1125899906842624 s : ok
2251799813685247 s : ok
-2251799813685248 s : ok
4503599627370495 s : ok
-4503599627370496 s : ok
9007199254740991 s : ok
-9007199254740992 s : ok
18014398509481983 s : ok
-18014398509481984 s : ok
36028797018963967 s : ok
-36028797018963968 s : ok
72057594037927935 s : ok
-72057594037927936 s : ok
144115188075855871 s : ok
-144115188075855872 s : ok
288230376151711743 s : ok
-288230376151711744 s : ok
576460752303423487 s : ok
-576460752303423488 s : ok
1152921504606846975 s : ok
-1152921504606846976 s : ok
2305843009213693951 s : ok
-2305843009213693952 s : ok
4611686018427387903 s : ok
-4611686018427387904 s : ok
9223372036854775807 s : ok
-9223372036854775808 s : ok
readonly:
1 us : adjtime() failed : Bad address fail
2 us : adjtime() failed : Bad address fail
4 us : adjtime() failed : Bad address fail
8 us : adjtime() failed : Bad address fail
16 us : adjtime() failed : Bad address fail
32 us : adjtime() failed : Bad address fail
64 us : adjtime() failed : Bad address fail
128 us : adjtime() failed : Bad address fail
256 us : adjtime() failed : Bad address fail
512 us : adjtime() failed : Bad address fail
1024 us : adjtime() failed : Bad address fail
2048 us : adjtime() failed : Bad address fail
4096 us : adjtime() failed : Bad address fail
8192 us : adjtime() failed : Bad address fail
16384 us : adjtime() failed : Bad address fail
32768 us : adjtime() failed : Bad address fail
65536 us : adjtime() failed : Bad address fail
131072 us : adjtime() failed : Bad address fail
262144 us : adjtime() failed : Bad address fail
524288 us : adjtime() failed : Bad address fail
1048576 us : adjtime() failed : Bad address fail
readwrite:
1 us : ok
2 us : ok
4 us : ok
8 us : ok
16 us : ok
32 us : ok
64 us : ok
128 us : ok
256 us : ok
512 us : ok
1024 us : ok
2048 us : ok
4096 us : ok
8192 us : ok
16384 us : ok
32768 us : ok
65536 us : ok
131072 us : ok
262144 us : ok
524288 us : ok
1048576 us : ok
slew:
512 us : 0 (16) 0 (256) 0 (4096) 0 (65536) 0 (1048576)
1024 us : 0 (16) 0 (256) 0 (4096) 0 (65536) 0 (1048576)
2048 us : 0 (16) 0 (256) 0 (4096) 0 (65536) 0 (1048576)
4096 us : 0 (16) 0 (256) 0 (4096) 0 (65536) 0 (1048576)
8192 us : 0 (16) 0 (256) 0 (4096) 0 (65536) 0 (1048576)
16384 us : 0 (16) 0 (256) 0 (4096) 0 (65536) 0 (1048576)
32768 us : 0 (16) 0 (256) 0 (4096) 0 (65536) 0 (1048576)
65536 us : 0 (16) 0 (256) 0 (4096) 0 (65536) 0 (1048576)
131072 us : 0 (16) 0 (256) 0 (4096) 0 (65536) 0 (1048576)
262144 us : 0 (16) 0 (256) 0 (4096) 0 (65536) 0 (1048576)
524288 us : 0 (16) 0 (256) 0 (4096) 0 (65536) 0 (1048576)
1048576 us : 16 (16) 256 (256) 500 (4096) 500 (65536) 5000 (1048576)
Bryan Christianson
bryan@xxxxxxxxxxxxx
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