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ntpd: decrease INITIAL_SAMPLES from 4 to 3

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This reduces initial traffic to NTP servers when a lot of devices boot at once.

Log inspection tells me we agressively burst-poll servers about 5 times
at startup, even though we usually already update clock after second replies.
INITIAL_SAMPLES can probably be even lower, e.g. 2, but let's be conservative
when changing this stuff.

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2021-03-02 12:07:14 +01:00
parent 70ee23399c
commit 2d6c175d9b
1 changed files with 12 additions and 15 deletions
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27
networking/ntpd.c
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@ -169,7 +169,7 @@
* datapoints after the step.
*/
#define INITIAL_SAMPLES 4 /* how many samples do we want for init */
#define INITIAL_SAMPLES 3 /* 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 factor */
@ -223,7 +223,16 @@
#define MIN_SELECTED 1 /* minimum intersection survivors */
#define MIN_CLUSTERED 3 /* minimum cluster survivors */
#define MAXDRIFT 0.000500 /* frequency drift we can correct (500 PPM) */
/* Correct frequency ourself (0) or let kernel do it (1)? */
#define USING_KERNEL_PLL_LOOP 1
// /* frequency drift we can correct (500 PPM) */
// #define MAXDRIFT 0.000500
// /* Compromise Allan intercept (sec). doc uses 1500, std ntpd uses 512 */
// #define ALLAN 512
// /* PLL loop gain */
// #define PLL 65536
// /* FLL loop gain [why it depends on MAXPOLL??] */
// #define FLL (MAXPOLL + 1)
/* Poll-adjust threshold.
* When we see that offset is small enough compared to discipline jitter,
@ -239,12 +248,6 @@
*/
#define POLLADJ_GATE 4
#define TIMECONST_HACK_GATE 2
/* Compromise Allan intercept (sec). doc uses 1500, std ntpd uses 512 */
#define ALLAN 512
/* PLL loop gain */
#define PLL 65536
/* FLL loop gain [why it depends on MAXPOLL??] */
#define FLL (MAXPOLL + 1)
/* Parameter averaging constant */
#define AVG 4
@ -372,9 +375,6 @@ typedef struct {
char p_hostname[1];
} peer_t;
#define USING_KERNEL_PLL_LOOP 1
enum {
OPT_n = (1 << 0),
OPT_q = (1 << 1),
@ -453,7 +453,7 @@ struct globals {
*/
#define G_precision_exp -9
/*
* G_precision_exp is used only for construction outgoing packets.
* G_precision_exp is used only for constructing outgoing packets.
* It's ok to set G_precision_sec to a slightly different value
* (One which is "nicer looking" in logs).
* Exact value would be (1.0 / (1 << (- G_precision_exp))):
@ -484,7 +484,6 @@ struct globals {
};
#define G (*ptr_to_globals)
#define VERB1 if (MAX_VERBOSE && G.verbose)
#define VERB2 if (MAX_VERBOSE >= 2 && G.verbose >= 2)
#define VERB3 if (MAX_VERBOSE >= 3 && G.verbose >= 3)
@ -989,7 +988,6 @@ send_query_to_peer(peer_t *p)
set_next(p, RESPONSE_INTERVAL);
}
/* Note that there is no provision to prevent several run_scripts
* to be started in quick succession. In fact, it happens rather often
* if initial syncronization results in a step.
@ -1767,7 +1765,6 @@ update_local_clock(peer_t *p)
return 1; /* "ok to increase poll interval" */
}
/*
* We've got a new reply packet from a peer, process it
* (helpers first)