new synchronization mechanism to align data collected to fixed steps

diff --git a/plugins.d/charts.d.plugin b/plugins.d/charts.d.plugin
index 9214b3091fde680ff5cbe4f4647ecce9699e981f..648bc78a0eff8ec7c81abf959d24defe7c813f72 100755 (executable)
--- a/plugins.d/charts.d.plugin
+++ b/plugins.d/charts.d.plugin
@@ -205,6 +205,7 @@ fi
 # loop control
 
 # default sleep function
+LOOPSLEEPMS_HIGHRES=0
 loopsleepms() {
        [ "$1" = "tellwork" ] && shift
        sleep $1
@@ -436,22 +437,26 @@ if [ -z "$run_charts" ]
        exit 1
 fi
 
-declare -A charts_last_update=() charts_min_dt=()
+declare -A charts_last_update=() charts_update_every=() charts_next_update=() chart_run_counter=()
 global_update() {
-       local exit_after=$((restart_timeout / update_every)) \
+       local exit_at \
                c=0 dt ret exec_start_ms exec_end_ms \
                chart now_charts=() next_charts=($run_charts)
 
        # return the current time in ms in $now_ms
        current_time_ms
 
+       exit_at=$(( now_ms + (restart_timeout * 1000) ))
+
        for chart in $run_charts
        do
-               eval "charts_min_dt[$chart]=\$$chart$suffix_update_every"
-               test -z "${charts_min_dt[$chart]}" && charts_min_dt[$charts]=$update_every
-               charts_last_update[$chart]=$((now_ms - (charts_min_dt[$chart] * 1000) ))
+               eval "charts_update_every[$chart]=\$$chart$suffix_update_every"
+               test -z "${charts_update_every[$chart]}" && charts_update_every[$charts]=$update_every
+               charts_last_update[$chart]=$((now_ms - (now_ms % (charts_update_every[$chart] * 1000) ) ))
+               charts_next_update[$chart]=$(( charts_last_update[$chart] + (charts_update_every[$chart] * 1000) ))
+               charts_run_counter[$chart]=0
 
-               echo "CHART netdata.plugin_$chart '' 'Execution time for $chart plugin' 'milliseconds / run' netdata netdata area 90000 ${charts_min_dt[$chart]}"
+               echo "CHART netdata.plugin_$chart '' 'Execution time for $chart plugin' 'milliseconds / run' netdata netdata area 90000 ${charts_update_every[$chart]}"
                echo "DIMENSION run_time 'run time' absolute 1 1"
        done
 
@@ -462,22 +467,35 @@ global_update() {
                now_charts=("${next_charts[@]}")
                next_charts=()
 
+               # return the current time in ms in $now_ms
+               current_time_ms
+
                for chart in "${now_charts[@]}"
                do
-                       # return the current time in ms in $now_ms
-                       current_time_ms
-                       dt=$(( (now_ms - charts_last_update[$chart]) * 1000 ))
-                       if [ $dt -ge $(( charts_min_dt[$chart] * 1000000 )) ]
+                       # echo >&2 "DEBUG: chart: $chart last: ${charts_last_update[$chart]}, next: ${charts_next_update[$chart]}, now: ${now_ms}"
+                       if [ ${now_ms} -ge ${charts_next_update[$chart]} ]
                        then
+                               dt=$(( (now_ms - charts_last_update[$chart]) ))
+                               #echo >&2 "DEBUG: chart: $chart last: ${charts_last_update[$chart]}, next: ${charts_next_update[$chart]}, now: ${now_ms}, dt: ${dt}"
+
                                charts_last_update[$chart]=$now_ms
 
+                               while [ ${charts_next_update[$chart]} -lt ${now_ms} ]
+                               do
+                                       charts_next_update[$chart]=$(( charts_next_update[$chart] + (charts_update_every[$chart] * 1000) ))
+                               done
+
                                # the first call should not give a duration
                                # so that netdata calibrates to current time
-                               test $c -eq 1 && dt=
+                               charts_run_counter[$chart]=$(( charts_run_counter[$chart] + 1 ))
+                               test ${charts_run_counter[$chart]} -eq 1 && dt=
+                               dt=$(( dt * 1000 ))
 
                                exec_start_ms=$now_ms
                                $chart$charts_update $dt
                                ret=$?
+                               
+                               # return the current time in ms in $now_ms
                                current_time_ms; exec_end_ms=$now_ms
 
                                echo "BEGIN netdata.plugin_$chart $dt"
@@ -501,10 +519,16 @@ global_update() {
                        suspend || ( echo >&2 "$PROGRAM_NAME: suspend returned error $?, falling back to sleep."; loopsleepms $debug_time $update_every $time_divisor)
                else
                        # wait the time you are required to
-                       loopsleepms $debug_time $update_every $time_divisor
+                       #loopsleepms $debug_time $update_every $time_divisor
+                       if [ ${LOOPSLEEPMS_HIGHRES} -eq 1 ]
+                               then
+                               sleep 0.2
+                       else
+                               sleep 1
+                       fi
                fi
 
-               test $c -gt $exit_after && exit 0
+               test ${now_ms} -ge ${exit_at} && exit 0
        done
 }