3ff3cb483
Denys Vlasenko
2025-10-11
Subject
ntpd: set tmx.maxerror properly - avoid STA_UNSYNC
Binary
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Architecture & Compiler Flags
gcc -Wp,-MD,applets/.usage.d -Wall -Wstrict-prototypes -O2 -fomit-frame-pointer -Iinclude -Iinclude -o applets/usage applets/usage.c
Build Log
(log yok)
Commit Diff GitHub →
networking/ntpd.c+12 -5
| @@ -1645,7 +1645,7 @@ update_local_clock(peer_t *p) | |
| /* 65536 is one ppm */ | |
| tmx.freq = G.discipline_freq_drift * 65536e6; | |
| #endif | |
| - | tmx.modes = ADJ_OFFSET | ADJ_STATUS | ADJ_TIMECONST;// | ADJ_MAXERROR | ADJ_ESTERROR; |
| + | tmx.modes = ADJ_OFFSET | ADJ_STATUS | ADJ_TIMECONST | ADJ_MAXERROR | ADJ_ESTERROR; |
| tmx.offset = (long)(offset * 1000000); /* usec */ | |
| if (SLEW_THRESHOLD < STEP_THRESHOLD) { | |
| @@ -1738,16 +1738,23 @@ update_local_clock(peer_t *p) | |
| if (tmx.constant < 0) | |
| tmx.constant = 0; | |
| - | //tmx.esterror = (uint32_t)(clock_jitter * 1e6); |
| - | //tmx.maxerror = (uint32_t)((sys_rootdelay / 2 + sys_rootdisp) * 1e6); |
| + | /* For ADJ_MAXERROR and ADJ_ESTERROR: */ |
| + | /* kernel increments this by 500us each second, sets STA_UNSYNC if exceeds 16 seconds: */ |
| + | tmx.maxerror = (uint32_t)((G.rootdelay / 2 + G.rootdisp) * 1000000.0); |
| + | /* (without ADJ_MAXERROR, time adjustment still works, but kernel uses |
| + | * conservative maxerror value and quickly sets STA_UNSYNC) |
| + | */ |
| + | /* esterror is not used by kernel, presumably may be used by other programs reading adjtimex result: */ |
| + | tmx.esterror = (uint32_t)(G.discipline_jitter * 1000000.0); |
| + | |
| rc = adjtimex(&tmx); | |
| if (rc < 0) | |
| bb_simple_perror_msg_and_die("adjtimex"); | |
| /* NB: here kernel returns constant == G.poll_exp, not == G.poll_exp - 4. | |
| * Not sure why. Perhaps it is normal. | |
| */ | |
| - | VERB4 bb_error_msg("adjtimex:%d freq:%ld offset:%+ld status:0x%x", |
| - | rc, (long)tmx.freq, (long)tmx.offset, tmx.status); |
| + | VERB4 bb_error_msg("adjtimex:%d freq:%ld offset:%+ld esterror:%ld maxerror:%ld status:0x%x", |
| + | rc, (long)tmx.freq, (long)tmx.offset, (long)tmx.esterror, (long)tmx.maxerror, tmx.status); |
| G.kernel_freq_drift = tmx.freq / 65536; | |
| VERB2 bb_error_msg("update from:%s offset:%+f delay:%f jitter:%f clock drift:%+.3fppm tc:%d", | |
| p->p_dotted, | |