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ntpd: fix a case when discipline_jitter = 0 if we step

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Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2012-03-05 10:18:00 +01:00
parent b3439d4727
commit 547ee7926e
1 changed files with 13 additions and 17 deletions
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30
networking/ntpd.c
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@ -340,7 +340,10 @@ struct globals {
double last_update_offset; // c.last double last_update_offset; // c.last
double last_update_recv_time; // s.t double last_update_recv_time; // s.t
double discipline_jitter; // c.jitter double discipline_jitter; // c.jitter
double offset_to_jitter_ratio; /* Since we only compare it with ints, can simplify code
* by not making this variable floating point:
*/
unsigned offset_to_jitter_ratio;
//double cluster_offset; // s.offset //double cluster_offset; // s.offset
//double cluster_jitter; // s.jitter //double cluster_jitter; // s.jitter
#if !USING_KERNEL_PLL_LOOP #if !USING_KERNEL_PLL_LOOP
@ -1339,7 +1342,7 @@ update_local_clock(peer_t *p)
return 1; /* "ok to increase poll interval" */ return 1; /* "ok to increase poll interval" */
} }
#endif #endif
offset = 0; abs_offset = offset = 0;
set_new_values(STATE_SYNC, offset, recv_time); set_new_values(STATE_SYNC, offset, recv_time);
} else { /* abs_offset <= STEP_THRESHOLD */ } else { /* abs_offset <= STEP_THRESHOLD */
@ -1356,10 +1359,6 @@ update_local_clock(peer_t *p)
etemp = SQUARE(G.discipline_jitter); etemp = SQUARE(G.discipline_jitter);
dtemp = SQUARE(offset - G.last_update_offset); dtemp = SQUARE(offset - G.last_update_offset);
G.discipline_jitter = SQRT(etemp + (dtemp - etemp) / AVG); G.discipline_jitter = SQRT(etemp + (dtemp - etemp) / AVG);
if (G.discipline_jitter < G_precision_sec)
G.discipline_jitter = G_precision_sec;
G.offset_to_jitter_ratio = fabs(offset) / G.discipline_jitter;
VERB3 bb_error_msg("discipline jitter=%f", G.discipline_jitter);
switch (G.discipline_state) { switch (G.discipline_state) {
case STATE_NSET: case STATE_NSET:
@ -1436,6 +1435,10 @@ update_local_clock(peer_t *p)
} }
} }
if (G.discipline_jitter < G_precision_sec)
G.discipline_jitter = G_precision_sec;
G.offset_to_jitter_ratio = abs_offset / G.discipline_jitter;
G.reftime = G.cur_time; G.reftime = G.cur_time;
G.ntp_status = p->lastpkt_status; G.ntp_status = p->lastpkt_status;
G.refid = p->lastpkt_refid; G.refid = p->lastpkt_refid;
@ -1473,7 +1476,7 @@ update_local_clock(peer_t *p)
memset(&tmx, 0, sizeof(tmx)); memset(&tmx, 0, sizeof(tmx));
if (adjtimex(&tmx) < 0) if (adjtimex(&tmx) < 0)
bb_perror_msg_and_die("adjtimex"); bb_perror_msg_and_die("adjtimex");
VERB3 bb_error_msg("p adjtimex freq:%ld offset:%+ld constant:%ld status:0x%x", bb_error_msg("p adjtimex freq:%ld offset:%+ld constant:%ld status:0x%x",
tmx.freq, tmx.offset, tmx.constant, tmx.status); tmx.freq, tmx.offset, tmx.constant, tmx.status);
} }
@ -1506,7 +1509,7 @@ update_local_clock(peer_t *p)
* To be on a safe side, let's do it only if offset is significantly * To be on a safe side, let's do it only if offset is significantly
* larger than jitter. * larger than jitter.
*/ */
if (tmx.constant > 0 && G.offset_to_jitter_ratio > TIMECONST_HACK_GATE) if (tmx.constant > 0 && G.offset_to_jitter_ratio >= TIMECONST_HACK_GATE)
tmx.constant--; tmx.constant--;
//tmx.esterror = (uint32_t)(clock_jitter * 1e6); //tmx.esterror = (uint32_t)(clock_jitter * 1e6);
@ -1520,7 +1523,7 @@ update_local_clock(peer_t *p)
VERB3 bb_error_msg("adjtimex:%d freq:%ld offset:%+ld status:0x%x", VERB3 bb_error_msg("adjtimex:%d freq:%ld offset:%+ld status:0x%x",
rc, tmx.freq, tmx.offset, tmx.status); rc, tmx.freq, tmx.offset, tmx.status);
G.kernel_freq_drift = tmx.freq / 65536; G.kernel_freq_drift = tmx.freq / 65536;
VERB2 bb_error_msg("update peer:%s, offset:%+f, jitter:%f, clock drift:%+.3f ppm, tc:%d", VERB2 bb_error_msg("update from:%s offset:%+f jitter:%f clock drift:%+.3fppm tc:%d",
p->p_dotted, offset, G.discipline_jitter, (double)tmx.freq / 65536, (int)tmx.constant); p->p_dotted, offset, G.discipline_jitter, (double)tmx.freq / 65536, (int)tmx.constant);
return 1; /* "ok to increase poll interval" */ return 1; /* "ok to increase poll interval" */
@ -1705,14 +1708,7 @@ recv_and_process_peer_pkt(peer_t *p)
* is increased, otherwise it is decreased. A bit of hysteresis * is increased, otherwise it is decreased. A bit of hysteresis
* helps calm the dance. Works best using burst mode. * helps calm the dance. Works best using burst mode.
*/ */
VERB4 if (rc > 0) { if (rc > 0 && G.offset_to_jitter_ratio <= POLLADJ_GATE) {
bb_error_msg("offset:%+f POLLADJ_GATE*discipline_jitter:%f poll:%s",
q->filter_offset, POLLADJ_GATE * G.discipline_jitter,
fabs(q->filter_offset) < POLLADJ_GATE * G.discipline_jitter
? "grows" : "falls"
);
}
if (rc > 0 && G.offset_to_jitter_ratio < POLLADJ_GATE) {
/* was += G.poll_exp but it is a bit /* was += G.poll_exp but it is a bit
* too optimistic for my taste at high poll_exp's */ * too optimistic for my taste at high poll_exp's */
G.polladj_count += MINPOLL; G.polladj_count += MINPOLL;