Do not force internal collectors to call rrdset_next. (#13926)

* Remove calls to rrdset_next().

* Rm checks plugin

* Update documentantion

* Call rrdset_next from within rrdset_done

This wraps up the removal of rrdset_next from internal collectors, which
removes a lot of unecessary code and the need for if/else clauses in
every place.

The pluginsd parser is the only component that calls rrdset_next*()
functions because it's not strictly speaking a collector but more of a
collector manager/proxy.

With the current changes it's possible to simplify the API we expose
from RRD significantly, but this will be follow-up work in the future.

* Remove stale reference to checks.plugin

* Fix RRD unit test

rrdset_next is not meant to be called from these tests.

* Fix db engine unit test.

* Schedule rrdset_next when we have completed at least one collection.

* Mark chart creation clauses as unlikely.

* Add missing brace to fix FreeBSD plugin.

1 files changed, 2 insertions, 8 deletions

diff --git a/collectors/idlejitter.plugin/plugin_idlejitter.c b/collectors/idlejitter.plugin/plugin_idlejitter.c
index 535819c69f..b6339cc0fc 100644
--- a/collectors/idlejitter.plugin/plugin_idlejitter.c
+++ b/collectors/idlejitter.plugin/plugin_idlejitter.c
@@ -47,18 +47,15 @@ void *cpuidlejitter_main(void *ptr) {
 
     usec_t update_every_ut = localhost->rrd_update_every * USEC_PER_SEC;
     struct timeval before, after;
-    unsigned long long counter;
 
-    for(counter = 0; 1 ;counter++) {
+    while (!netdata_exit) {
         int iterations = 0;
         usec_t error_total = 0,
                 error_min = 0,
                 error_max = 0,
                 elapsed = 0;
 
-        if(netdata_exit) break;
-
-        while(elapsed < update_every_ut) {
+        while (elapsed < update_every_ut) {
             now_monotonic_high_precision_timeval(&before);
             worker_is_idle();
             sleep_usec(sleep_ut);
@@ -82,10 +79,7 @@ void *cpuidlejitter_main(void *ptr) {
             iterations++;
         }
 
-        if(netdata_exit) break;
-
         if(iterations) {
-            if (likely(counter)) rrdset_next(st);
             rrddim_set_by_pointer(st, rd_min, error_min);
             rrddim_set_by_pointer(st, rd_max, error_max);
             rrddim_set_by_pointer(st, rd_avg, error_total / iterations);