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# no need for shebang - this file is included from other scripts
LOOPSLEEP_DATE="$(which date 2>/dev/null || command -v date 2>/dev/null)"
if [ -z "$LOOPSLEEP_DATE" ]
then
echo >&2 "$0: ERROR: Cannot find the command 'date' in the system path."
exit 1
fi
# -----------------------------------------------------------------------------
# use the date command as a high resolution timer
now_ms=
LOOPSLEEPMS_HIGHRES=1
test "$($LOOPSLEEP_DATE +%N)" = "%N" && LOOPSLEEPMS_HIGHRES=0
test -z "$($LOOPSLEEP_DATE +%N)" && LOOPSLEEPMS_HIGHRES=0
current_time_ms_from_date() {
if [ $LOOPSLEEPMS_HIGHRES -eq 0 ]
then
now_ms="$($LOOPSLEEP_DATE +'%s')000"
else
now_ms="$(( $( $LOOPSLEEP_DATE +'%s * 1000 + %-N / 1000000' ) ))"
fi
}
# -----------------------------------------------------------------------------
# use /proc/uptime as a high resolution timer
current_time_ms_from_date
current_time_ms_from_uptime_started="${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
}
# -----------------------------------------------------------------------------
# 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.
LOOPSLEEPMS_LASTRUN=0
LOOPSLEEPMS_NEXTRUN=0
LOOPSLEEPMS_LASTSLEEP=0
LOOPSLEEPMS_LASTWORK=0
loopsleepms() {
local tellwork=0 t="${1}" div s m now mstosleep
if [ "${t}" = "tellwork" ]
then
tellwork=1
shift
t="${1}"
fi
# $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 in ${now_ms}
${current_time_ms}
# calculate ms since last run
[ ${LOOPSLEEPMS_LASTRUN} -gt 0 ] && \
LOOPSLEEPMS_LASTWORK=$((now_ms - LOOPSLEEPMS_LASTRUN - LOOPSLEEPMS_LASTSLEEP + current_time_ms_accuracy))
# echo "# last loop's work took $LOOPSLEEPMS_LASTWORK ms"
# remember this run
LOOPSLEEPMS_LASTRUN=${now_ms}
# calculate the next run
LOOPSLEEPMS_NEXTRUN=$(( ( now_ms - ( now_ms % ( t * 1000 ) ) ) + ( t * 1000 ) ))
# calculate ms to sleep
mstosleep=$(( LOOPSLEEPMS_NEXTRUN - now_ms + current_time_ms_accuracy ))
# echo "# mstosleep is $mstosleep ms"
# if we are too slow, sleep some time
test ${mstosleep} -lt 200 && mstosleep=200
s=$(( mstosleep / 1000 ))
m=$(( mstosleep - (s * 1000) ))
[ "${m}" -lt 100 ] && m="0${m}"
[ "${m}" -lt 10 ] && m="0${m}"
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
${mysleep} ${s}.${m}
# keep the values we need
# for our next run
LOOPSLEEPMS_LASTSLEEP=$mstosleep
}
# test it
#while [ 1 ]
#do
# r=$(( (RANDOM * 2000 / 32767) ))
# s=$((r / 1000))
# m=$((r - (s * 1000)))
# [ "${m}" -lt 100 ] && m="0${m}"
# [ "${m}" -lt 10 ] && m="0${m}"
# echo "${r} = ${s}.${m}"
#
# # the work
# ${mysleep} ${s}.${m}
#
# # the alignment loop
# loopsleepms tellwork 1
#done
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