1 files changed, 90 insertions, 0 deletions
diff --git a/plugins.d/loopsleepms.sh.inc b/plugins.d/loopsleepms.sh.inc
new file mode 100644
index 000000000..2e22de3d8
--- /dev/null
+++ b/plugins.d/loopsleepms.sh.inc
@@ -0,0 +1,90 @@
+#!/bin/bash
+
+# this function is used to sleep a fraction of a second
+# it calculates the difference between every time is called
+# and tries to align the sleep time to give you exactly the
+# loop you need.
+
+LOOPSLEEP_DATE="$(which date)"
+if [ -z "$LOOPSLEEP_DATE" ]
+	then
+	echo >&2 "$0: ERROR: Cannot find the command 'date' in the system path."
+	exit 1
+fi
+
+LOOPSLEEPMS_LASTRUN=0
+LOOPSLEEPMS_LASTSLEEP=0
+LOOPSLEEPMS_LASTWORK=0
+
+LOOPSLEEPMS_HIGHRES=1
+test "$($LOOPSLEEP_DATE +%N)" = "%N" && LOOPSLEEPMS_HIGHRES=0
+
+now_ms=
+current_time_ms() {
+	# if high resolution is not supported
+	# just sleep the time requested, in seconds
+	if [ $LOOPSLEEPMS_HIGHRES -eq 0 ]
+	then
+		now_ms="$($LOOPSLEEP_DATE +'%s')000"
+	else
+		now_ms="$(( $( $LOOPSLEEP_DATE +'%s * 1000 + %-N / 1000000' ) ))"
+	fi
+}
+
+loopsleepms() {
+	local tellwork=0 t="$1" div s m now mstosleep
+
+	if [ "$t" = "tellwork" ]
+	then
+		tellwork=1
+		shift
+		t="$1"
+	fi
+	div="${2-100}"
+
+	# $t = the time in seconds to wait
+
+	# if high resolution is not supported
+	# just sleep the time requested, in seconds
+	if [ $LOOPSLEEPMS_HIGHRES -eq 0 ]
+	then
+		sleep $t
+		return
+	fi
+
+	# get the current time, in ms
+	# milliseconds since epoch (1-1-1970)
+	now="$(( $( $LOOPSLEEP_DATE +'%s * 1000 + %-N / 1000000' ) ))"
+
+	# calculate required sleep in ms
+	t=$((t * 1000 * div / 100))
+
+	# this is our first run
+	# just wait the requested time
+	test $LOOPSLEEPMS_LASTRUN -eq 0 && LOOPSLEEPMS_LASTRUN=$now
+
+	# calculate ms since last run
+	LOOPSLEEPMS_LASTWORK=$((now - LOOPSLEEPMS_LASTRUN - LOOPSLEEPMS_LASTSLEEP))
+	# echo "# last loop's work took $LOOPSLEEPMS_LASTWORK ms"
+
+	# calculate ms to sleep
+	mstosleep=$(( t - LOOPSLEEPMS_LASTWORK ))
+	# echo "# mstosleep is $mstosleep ms"
+
+	# if we are too slow, sleep some time
+	test $mstosleep -lt 200 && mstosleep=200
+
+	s=$((mstosleep / 1000))
+	m=$((mstosleep - (s * 1000)))
+
+	test $tellwork -eq 1 && echo >&2 " >>> PERFORMANCE >>> WORK TOOK $LOOPSLEEPMS_LASTWORK ms ( $((LOOPSLEEPMS_LASTWORK * 100 / 1000)).$((LOOPSLEEPMS_LASTWORK % 10))% cpu ) >>> SLEEPING $mstosleep ms"
+
+	# echo "# sleeping $s.$m"
+	# echo
+	sleep $s.$m
+
+	# keep the values we need
+	# for our next run
+	LOOPSLEEPMS_LASTRUN=$now
+	LOOPSLEEPMS_LASTSLEEP=$mstosleep
+}