-#!/bin/bash
+# no need for shebang - this file is included from other scripts
-# 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="$(which date)"
+LOOPSLEEP_DATE="$(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
+ then
+ echo >&2 "$0: ERROR: Cannot find the command 'date' in the system path."
+ exit 1
fi
-LOOPSLEEPMS_LASTRUN=0
-LOOPSLEEPMS_LASTSLEEP=0
-LOOPSLEEPMS_LASTWORK=0
+# -----------------------------------------------------------------------------
+# use the date command as a high resolution timer
+now_ms=
LOOPSLEEPMS_HIGHRES=1
test "$($LOOPSLEEP_DATE +%N)" = "%N" && LOOPSLEEPMS_HIGHRES=0
+test -z "$($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
+}
-now_ms=
-current_time_ms() {
- # if high resolution is not supported
- # just sleep the time requested, in seconds
- if [ $LOOPSLEEPMS_HIGHRES -eq 0 ]
- then
- now_ms="$($LOOPSLEEP_DATE +'%s')000"
- else
- now_ms="$(( $( $LOOPSLEEP_DATE +'%s * 1000 + %-N / 1000000' ) ))"
- fi
+# -----------------------------------------------------------------------------
+# use /proc/uptime as a high resolution timer
+
+current_time_ms_from_date
+current_time_ms_from_uptime_started="${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="$1"
- fi
- div="${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
+ 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
projects / netdata.git / blobdiff