e8ce28539
Denys Vlasenko
2012-03-03
Subject
ntpd: avoid printing messages between send and recv. good for fast networks
Binary
No binary (build failed)
Architecture & Compiler Flags
—
Build Log
(log yok)
Commit Diff GitHub →
networking/ntpd.c+30 -7
| @@ -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) { | |