| b.liu | e958203 | 2025-04-17 19:18:16 +0800 | [diff] [blame^] | 1 | Adjust the reaction to a polling interval timestamp that references |
| 2 | to a past time. |
| 3 | |
| 4 | Past timestamps can happen when ntpd adjusts router's time after network |
| 5 | connectivity is obtained after boot. Collectd shows warnings for each plugin |
| 6 | as it tries to enter new values with the same timestamp as the previous one. |
| 7 | |
| 8 | This patch adjusts the next polling time to be now+2 seconds for the main |
| 9 | loop and for the plugin-specific read loops. That avoids the warnings, but |
| 10 | does not overreact in case there are shorter polling intervals or the time |
| 11 | gets adjusted for other reasons. |
| 12 | |
| 13 | Additionally some debug statements are added, but they are visible only |
| 14 | when --enable-debug configure option is used in Makefile. |
| 15 | |
| 16 | |
| 17 | --- a/src/daemon/collectd.c |
| 18 | +++ b/src/daemon/collectd.c |
| 19 | @@ -274,20 +274,23 @@ static int do_loop(void) { |
| 20 | update_kstat(); |
| 21 | #endif |
| 22 | |
| 23 | + DEBUG("do_loop before plugin_read_all: now = %.3f", CDTIME_T_TO_DOUBLE(cdtime())); |
| 24 | /* Issue all plugins */ |
| 25 | plugin_read_all(); |
| 26 | |
| 27 | cdtime_t now = cdtime(); |
| 28 | + DEBUG("do_loop after plugin_read_all: now = %.3f, wait_until= %.3f", CDTIME_T_TO_DOUBLE(now), CDTIME_T_TO_DOUBLE(wait_until)); |
| 29 | if (now >= wait_until) { |
| 30 | - WARNING("Not sleeping because the next interval is " |
| 31 | + WARNING("Sleeping only 2s because the next interval is " |
| 32 | "%.3f seconds in the past!", |
| 33 | CDTIME_T_TO_DOUBLE(now - wait_until)); |
| 34 | - wait_until = now + interval; |
| 35 | - continue; |
| 36 | + wait_until = now + DOUBLE_TO_CDTIME_T(2); |
| 37 | + DEBUG("do_loop: wait_until adjusted to now+2 = %.3f", CDTIME_T_TO_DOUBLE(wait_until)); |
| 38 | } |
| 39 | |
| 40 | struct timespec ts_wait = CDTIME_T_TO_TIMESPEC(wait_until - now); |
| 41 | wait_until = wait_until + interval; |
| 42 | + DEBUG("do_loop ends: wait_until set to %.3f", CDTIME_T_TO_DOUBLE(wait_until)); |
| 43 | |
| 44 | while ((loop == 0) && (nanosleep(&ts_wait, &ts_wait) != 0)) { |
| 45 | if (errno != EINTR) { |
| 46 | --- a/src/daemon/plugin.c |
| 47 | +++ b/src/daemon/plugin.c |
| 48 | @@ -585,10 +585,11 @@ static void *plugin_read_thread(void __a |
| 49 | |
| 50 | /* Check, if `rf_next_read' is in the past. */ |
| 51 | if (rf->rf_next_read < now) { |
| 52 | - /* `rf_next_read' is in the past. Insert `now' |
| 53 | + /* `rf_next_read' is in the past. Insert `now'+2s |
| 54 | * so this value doesn't trail off into the |
| 55 | * past too much. */ |
| 56 | - rf->rf_next_read = now; |
| 57 | + rf->rf_next_read = now + DOUBLE_TO_CDTIME_T(2); |
| 58 | + DEBUG("plugin_read_thread: Next read is in the past. Adjusted to now+2s"); |
| 59 | } |
| 60 | |
| 61 | DEBUG("plugin_read_thread: Next read of the `%s' plugin at %.3f.", |