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ntpd: calculate offset to jitter ratio before updating jitter

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The offset to jitter ratio is now calculated before updating
jitter to make the test more sensitive.

function                                             old     new   delta
ntp_init                                             460     474     +14
update_local_clock                                   752     764     +12
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 2/0 up/down: 26/0)               Total: 26 bytes

Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Miroslav Lichvar 2014-10-05 03:10:15 +02:00 committed by Denys Vlasenko
parent cd73871178
commit 760d035699
1 changed files with 8 additions and 4 deletions
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12
networking/ntpd.c
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@ -1488,12 +1488,19 @@ update_local_clock(peer_t *p)
} else { /* abs_offset <= STEP_THRESHOLD */
/* The ratio is calculated before jitter is updated to make
* poll adjust code more sensitive to large offsets.
*/
G.offset_to_jitter_ratio = abs_offset / G.discipline_jitter;
/* Compute the clock jitter as the RMS of exponentially
* weighted offset differences. Used by the poll adjust code.
*/
etemp = SQUARE(G.discipline_jitter);
dtemp = SQUARE(offset - G.last_update_offset);
G.discipline_jitter = SQRT(etemp + (dtemp - etemp) / AVG);
if (G.discipline_jitter < G_precision_sec)
G.discipline_jitter = G_precision_sec;
switch (G.discipline_state) {
case STATE_NSET:
@ -1570,10 +1577,6 @@ 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.ntp_status = p->lastpkt_status;
G.refid = p->lastpkt_refid;
@ -2111,6 +2114,7 @@ static NOINLINE void ntp_init(char **argv)
bb_error_msg_and_die(bb_msg_you_must_be_root);
/* Set some globals */
G.discipline_jitter = G_precision_sec;
G.stratum = MAXSTRAT;
if (BURSTPOLL != 0)
G.poll_exp = BURSTPOLL; /* speeds up initial sync */