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ntpd: increase minimum G.FREQHOLD_cnt from 8 to 10

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With ~0.9 initiall offsets, using 8 results in a bit too eager
frequency correction.

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2018-07-02 16:17:07 +02:00
parent 0dbcb46af5
commit 029bd187bd
1 changed files with 4 additions and 3 deletions
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7
networking/ntpd.c
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@ -149,6 +149,7 @@
*/
#define INITIAL_SAMPLES 4 /* how many samples do we want for init */
#define MIN_FREQHOLD 10 /* adjust offset, but not freq in this many first adjustments */
#define BAD_DELAY_GROWTH 4 /* drop packet if its delay grew by more than this */
#define RETRY_INTERVAL 32 /* on send/recv error, retry in N secs (need to be power of 2) */
@ -1753,7 +1754,7 @@ update_local_clock(peer_t *p)
//15:19:39.114 update from:<IP> offset:+0.327022 delay:0.158384 jitter:0.108538 clock drift:-1.393ppm tc:4
//15:20:12.715 update from:<IP> offset:+0.275596 delay:0.158297 jitter:0.097292 clock drift:-1.393ppm tc:4
//15:20:45.111 update from:<IP> offset:+0.225715 delay:0.158271 jitter:0.087841 clock drift:-1.393ppm tc:4
// If allwed to continue, it would start increasing tmx.freq now.
// If allowed to continue, it would start increasing tmx.freq now.
// Instead, it was ^Ced, and started anew:
//15:21:15.043 no valid datapoints, no peer selected
//15:21:17.408 update from:<IP> offset:+0.175910 delay:0.158314 jitter:0.076683 clock drift:-1.393ppm tc:4
@ -1776,9 +1777,9 @@ update_local_clock(peer_t *p)
//15:31:53.473 update from:<IP> offset:+0.000007 delay:0.158142 jitter:0.010922 clock drift:+9.343ppm tc:6
//15:32:58.902 update from:<IP> offset:-0.000728 delay:0.158222 jitter:0.009454 clock drift:+9.298ppm tc:6
/*
* This expression would choose 15 in the above example.
* This expression would choose MIN_FREQHOLD + 7 in the above example.
*/
G.FREQHOLD_cnt = 8 + ((unsigned)(abs(tmx.offset)) >> 16);
G.FREQHOLD_cnt = MIN_FREQHOLD + ((unsigned)(abs(tmx.offset)) >> 16);
}
G.FREQHOLD_cnt--;
tmx.status |= STA_FREQHOLD;