+# -----------------------------------------------------------------------------
+# use /proc/uptime as a high resolution timer
+
+current_time_ms_from_date
+current_time_ms_from_uptime_started="${now_ms}"
+current_time_ms_from_uptime_last="${now_ms}"
+current_time_ms_from_uptime_first=0
+current_time_ms_from_uptime() {
+ local up rest arr=() n
+
+ read up rest </proc/uptime
+ if [ $? -ne 0 ]
+ then
+ echo >&2 "$0: Cannot read /proc/uptime - falling back to current_time_ms_from_date()."
+ current_time_ms="current_time_ms_from_date"
+ current_time_ms_from_date
+ current_time_ms_accuracy=1
+ return
+ fi
+
+ arr=(${up//./ })
+
+ if [ ${#arr[1]} -lt 1 ]
+ then
+ n="${arr[0]}000"
+ elif [ ${#arr[1]} -lt 2 ]
+ then
+ n="${arr[0]}${arr[1]}00"
+ elif [ ${#arr[1]} -lt 3 ]
+ then
+ n="${arr[0]}${arr[1]}0"
+ else
+ n="${arr[0]}${arr[1]}"
+ fi
+
+ now_ms=$((current_time_ms_from_uptime_started - current_time_ms_from_uptime_first + n))
+
+ if [ "${now_ms}" -lt "${current_time_ms_from_uptime_last}" ]
+ then
+ echo >&2 "$0: Cannot use current_time_ms_from_uptime() - new time ${now_ms} is older than the last ${current_time_ms_from_uptime_last} - falling back to current_time_ms_from_date()."
+ current_time_ms="current_time_ms_from_date"
+ current_time_ms_from_date
+ current_time_ms_accuracy=1
+ fi
+
+ current_time_ms_from_uptime_last="${now_ms}"
+}
+current_time_ms_from_uptime
+current_time_ms_from_uptime_first="$((now_ms - current_time_ms_from_uptime_started))"
+current_time_ms_from_uptime_last="${current_time_ms_from_uptime_first}"
+current_time_ms="current_time_ms_from_uptime"
+current_time_ms_accuracy=10
+if [ "${current_time_ms_from_uptime_first}" -eq 0 ]
+ then
+ echo >&2 "$0: Invalid setup for current_time_ms_from_uptime() - falling back to current_time_ms_from_date()."
+ current_time_ms="current_time_ms_from_date"
+ current_time_ms_accuracy=1
+fi
+
+# -----------------------------------------------------------------------------
+# use read with timeout for sleep
+
+mysleep="mysleep_read"
+
+mysleep_fifo="${NETDATA_CACHE_DIR-/tmp}/.netdata_bash_sleep_timer_fifo"
+[ ! -e "${mysleep_fifo}" ] && mkfifo "${mysleep_fifo}"
+[ ! -e "${mysleep_fifo}" ] && mysleep="sleep"
+
+mysleep_read() {
+ read -t "${1}" <>"${mysleep_fifo}"
+ ret=$?
+ if [ $ret -le 128 ]
+ then
+ echo >&2 "$0: Cannot use read for sleeping (return code ${ret})."
+ mysleep="sleep"
+ ${mysleep} "${1}"
+ fi