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authorDenys Vlasenko <vda.linux@googlemail.com>2012-03-03 11:15:46 (GMT)
committer Denys Vlasenko <vda.linux@googlemail.com>2012-03-03 11:15:46 (GMT)
commite8ce285395d801e551811ed3eb9df25a6d46df0e (patch)
treefcc67670287e2a8e3ab95f9c539cd53ef7761927
parentb124c3491b8cb86dd7e978c375aa2b83eaca1462 (diff)
downloadbusybox-e8ce285395d801e551811ed3eb9df25a6d46df0e.tar.gz
busybox-e8ce285395d801e551811ed3eb9df25a6d46df0e.tar.bz2
ntpd: avoid printing messages between send and recv. good for fast networks
function old new delta ntpd_main 887 929 +42 Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
-rw-r--r--networking/ntpd.c37
1 files changed, 30 insertions, 7 deletions
diff --git a/networking/ntpd.c b/networking/ntpd.c
index e86f72f..938c7f0 100644
--- a/networking/ntpd.c
+++ b/networking/ntpd.c
@@ -107,7 +107,10 @@
#define FREQ_TOLERANCE 0.000015 /* frequency tolerance (15 PPM) */
#define BURSTPOLL 0 /* initial poll */
#define MINPOLL 5 /* minimum poll interval. std ntpd uses 6 (6: 64 sec) */
-#define BIGPOLL 10 /* drop to lower poll at any trouble (10: 17 min) */
+/* If offset > discipline_jitter * POLLADJ_GATE, and poll interval is >= 2^BIGPOLL,
+ * then it is decreased _at once_. (If < 2^BIGPOLL, it will be decreased _eventually_).
+ */
+#define BIGPOLL 10 /* 2^10 sec ~= 17 min */
#define MAXPOLL 12 /* maximum poll interval (12: 1.1h, 17: 36.4h). std ntpd uses 17 */
/* Actively lower poll when we see such big offsets.
* With STEP_THRESHOLD = 0.125, it means we try to sync more aggressively
@@ -124,13 +127,13 @@
/* Poll-adjust threshold.
* When we see that offset is small enough compared to discipline jitter,
- * we grow a counter: += MINPOLL. When it goes over POLLADJ_LIMIT,
+ * we grow a counter: += MINPOLL. When counter goes over POLLADJ_LIMIT,
* we poll_exp++. If offset isn't small, counter -= poll_exp*2,
- * and when it goes below -POLLADJ_LIMIT, we poll_exp--
- * (bumped from 30 to 40 since otherwise I often see poll_exp going *2* steps down)
+ * and when it goes below -POLLADJ_LIMIT, we poll_exp--.
+ * (Bumped from 30 to 40 since otherwise I often see poll_exp going *2* steps down)
*/
#define POLLADJ_LIMIT 40
-/* If offset < POLLADJ_GATE * discipline_jitter, then we can increase
+/* If offset < discipline_jitter * POLLADJ_GATE, then we decide to increase
* poll interval (we think we can't improve timekeeping
* by staying at smaller poll).
*/
@@ -732,6 +735,12 @@ send_query_to_peer(peer_t *p)
free(local_lsa);
}
+ /* Emit message _before_ attempted send. Think of a very short
+ * roundtrip networks: we need to go back to recv loop ASAP,
+ * to reduce delay. Printing messages after send works against that.
+ */
+ VERB1 bb_error_msg("sending query to %s", p->p_dotted);
+
/*
* Send out a random 64-bit number as our transmit time. The NTP
* server will copy said number into the originate field on the
@@ -759,7 +768,6 @@ send_query_to_peer(peer_t *p)
}
p->reachable_bits <<= 1;
- VERB1 bb_error_msg("sent query to %s", p->p_dotted);
set_next(p, RESPONSE_INTERVAL);
}
@@ -2077,8 +2085,23 @@ int ntpd_main(int argc UNUSED_PARAM, char **argv)
timeout++; /* (nextaction - G.cur_time) rounds down, compensating */
/* Here we may block */
- VERB2 bb_error_msg("poll %us, sockets:%u, poll interval:%us", timeout, i, 1 << G.poll_exp);
+ VERB2 {
+ if (i > ENABLE_FEATURE_NTPD_SERVER) {
+ /* We wait for at least one reply.
+ * Poll for it, without wasting time for message.
+ * Since replies often come under 1 second, this also
+ * reduces clutter in logs.
+ */
+ nfds = poll(pfd, i, 1000);
+ if (nfds != 0)
+ goto did_poll;
+ if (--timeout <= 0)
+ goto did_poll;
+ }
+ bb_error_msg("poll %us, sockets:%u, poll interval:%us", timeout, i, 1 << G.poll_exp);
+ }
nfds = poll(pfd, i, timeout * 1000);
+ did_poll:
gettime1900d(); /* sets G.cur_time */
if (nfds <= 0) {
if (G.script_name && G.cur_time - G.last_script_run > 11*60) {