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authorDenys Vlasenko <vda.linux@googlemail.com>2018-07-02 16:17:07 +0200
committerDenys Vlasenko <vda.linux@googlemail.com>2018-07-02 16:18:34 +0200
commit029bd187bdad5bfd7771ed356e633e8ec8044d2e (patch)
tree7fdd8faa810296748e45b6a621c104360cb1f1ba
parent0dbcb46af50ab273e03f3a6e4ae93912aa1f2f35 (diff)
downloadbusybox-029bd187bdad5bfd7771ed356e633e8ec8044d2e.tar.gz
ntpd: increase minimum G.FREQHOLD_cnt from 8 to 10
With ~0.9 initiall offsets, using 8 results in a bit too eager frequency correction. Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
-rw-r--r--networking/ntpd.c7
1 files changed, 4 insertions, 3 deletions
diff --git a/networking/ntpd.c b/networking/ntpd.c
index a1b8ac5b0..7b800369e 100644
--- a/networking/ntpd.c
+++ b/networking/ntpd.c
@@ -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;