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| author | Denys Vlasenko <vda.linux@googlemail.com> | 2019-10-30 12:13:46 +0100 |
|---|---|---|
| committer | Denys Vlasenko <vda.linux@googlemail.com> | 2019-10-30 12:18:07 +0100 |
| commit | ea096d6c1389c93bdb6c6c45a04aff9062c7d8cf (patch) | |
| tree | 509ec77841766251b090e145d7435c4688cf0762 /networking | |
| parent | 6b4960155e94076bf25518e4e268a7a5f849308e (diff) | |
| download | busybox-ea096d6c1389c93bdb6c6c45a04aff9062c7d8cf.tar.gz | |
ntpd: decrease MIN_FREQHOLD by 2, increase "penalty" for largish offset x2
> 2018-07-25:
> ntpd: increase MIN_FREQHOLD by 3
> This means we'll start correcting frequency ~5 minutes after start,
> not ~3.5 ones.
> With previous settings I still often see largish ~0.7s initial offsets
> only about 1/2 corrected before frequency correction kicks in,
> resulting in ~200ppm "correction" which is then slowly undone.
Review of real-world results of the above shows that with small
initial offsets, freq correction can be allowed to kick in sooner,
whereas with large (~0.8s) offsets, we still start freq correction
a bit too soon.
Let's rebalance this a bit.
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Diffstat (limited to 'networking')
| -rw-r--r-- | networking/ntpd.c | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/networking/ntpd.c b/networking/ntpd.c index e11160a55..0f12409f9 100644 --- a/networking/ntpd.c +++ b/networking/ntpd.c @@ -164,7 +164,7 @@ */ #define INITIAL_SAMPLES 4 /* how many samples do we want for init */ -#define MIN_FREQHOLD 12 /* adjust offset, but not freq in this many first adjustments */ +#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 factor */ #define RETRY_INTERVAL 32 /* on send/recv error, retry in N secs (need to be power of 2) */ @@ -1876,11 +1876,11 @@ 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 MIN_FREQHOLD + 8 in the above example - * (off_065 is +1 for each 0.065536 seconds of offset). + * This expression would choose MIN_FREQHOLD + 14 in the above example + * (off_032 is +1 for each 0.032768 seconds of offset). */ - unsigned off_065 = abs((int)(tmx.offset >> 16)); - G.FREQHOLD_cnt = 1 + MIN_FREQHOLD + off_065; + unsigned off_032 = abs((int)(tmx.offset >> 15)); + G.FREQHOLD_cnt = 1 + MIN_FREQHOLD + off_032; } G.FREQHOLD_cnt--; tmx.status |= STA_FREQHOLD; |