1 # no need for shebang - this file is included from other scripts
3 LOOPSLEEP_DATE="$(which date)"
4 if [ -z "$LOOPSLEEP_DATE" ]
6 echo >&2 "$0: ERROR: Cannot find the command 'date' in the system path."
10 # -----------------------------------------------------------------------------
11 # use the date command as a high resolution timer
15 test "$($LOOPSLEEP_DATE +%N)" = "%N" && LOOPSLEEPMS_HIGHRES=0
16 test -z "$($LOOPSLEEP_DATE +%N)" && LOOPSLEEPMS_HIGHRES=0
17 current_time_ms_from_date() {
18 if [ $LOOPSLEEPMS_HIGHRES -eq 0 ]
20 now_ms="$($LOOPSLEEP_DATE +'%s')000"
22 now_ms="$(( $( $LOOPSLEEP_DATE +'%s * 1000 + %-N / 1000000' ) ))"
26 # -----------------------------------------------------------------------------
27 # use /proc/uptime as a high resolution timer
29 current_time_ms_from_date
30 current_time_ms_from_uptime_started="${now_ms}"
31 current_time_ms_from_uptime_last="${now_ms}"
32 current_time_ms_from_uptime_first=0
33 current_time_ms_from_uptime() {
34 local up rest arr=() n
36 read up rest </proc/uptime
39 echo >&2 "$0: Cannot read /proc/uptime - falling back to current_time_ms_from_date()."
40 current_time_ms="current_time_ms_from_date"
41 current_time_ms_from_date
42 current_time_ms_accuracy=1
48 if [ ${#arr[1]} -lt 1 ]
51 elif [ ${#arr[1]} -lt 2 ]
53 n="${arr[0]}${arr[1]}00"
54 elif [ ${#arr[1]} -lt 3 ]
56 n="${arr[0]}${arr[1]}0"
58 n="${arr[0]}${arr[1]}"
61 now_ms=$((current_time_ms_from_uptime_started - current_time_ms_from_uptime_first + n))
63 if [ "${now_ms}" -lt "${current_time_ms_from_uptime_last}" ]
65 echo >&2 "$0: Cannot use current_time_ms_from_uptime() - new time ${now_ms} is older than the last ${current_time_ms_from_uptime_last} - falling back to current_time_ms_from_date()."
66 current_time_ms="current_time_ms_from_date"
67 current_time_ms_from_date
68 current_time_ms_accuracy=1
71 current_time_ms_from_uptime_last="${now_ms}"
73 current_time_ms_from_uptime
74 current_time_ms_from_uptime_first="$((now_ms - current_time_ms_from_uptime_started))"
75 current_time_ms_from_uptime_last="${current_time_ms_from_uptime_first}"
76 current_time_ms="current_time_ms_from_uptime"
77 current_time_ms_accuracy=10
78 if [ "${current_time_ms_from_uptime_first}" -eq 0 ]
80 echo >&2 "$0: Invalid setup for current_time_ms_from_uptime() - falling back to current_time_ms_from_date()."
81 current_time_ms="current_time_ms_from_date"
82 current_time_ms_accuracy=1
85 # -----------------------------------------------------------------------------
86 # use read with timeout for sleep
88 mysleep="mysleep_read"
90 mysleep_fifo="${NETDATA_CACHE_DIR-/tmp}/.netdata_bash_sleep_timer_fifo"
91 [ ! -e "${mysleep_fifo}" ] && mkfifo "${mysleep_fifo}"
92 [ ! -e "${mysleep_fifo}" ] && mysleep="sleep"
95 read -t "${1}" <>"${mysleep_fifo}"
99 echo >&2 "$0: Cannot use read for sleeping (return code ${ret})."
106 # -----------------------------------------------------------------------------
107 # this function is used to sleep a fraction of a second
108 # it calculates the difference between every time is called
109 # and tries to align the sleep time to give you exactly the
112 LOOPSLEEPMS_LASTRUN=0
113 LOOPSLEEPMS_NEXTRUN=0
114 LOOPSLEEPMS_LASTSLEEP=0
115 LOOPSLEEPMS_LASTWORK=0
118 local tellwork=0 t="${1}" div s m now mstosleep
120 if [ "${t}" = "tellwork" ]
127 # $t = the time in seconds to wait
129 # if high resolution is not supported
130 # just sleep the time requested, in seconds
131 if [ ${LOOPSLEEPMS_HIGHRES} -eq 0 ]
137 # get the current time, in ms in ${now_ms}
140 # calculate ms since last run
141 [ ${LOOPSLEEPMS_LASTRUN} -gt 0 ] && \
142 LOOPSLEEPMS_LASTWORK=$((now_ms - LOOPSLEEPMS_LASTRUN - LOOPSLEEPMS_LASTSLEEP))
143 # echo "# last loop's work took $LOOPSLEEPMS_LASTWORK ms"
146 LOOPSLEEPMS_LASTRUN=${now_ms}
148 # calculate the next run
149 LOOPSLEEPMS_NEXTRUN=$(( ( now_ms - ( now_ms % ( t * 1000 ) ) ) + ( t * 1000 ) ))
151 # calculate ms to sleep
152 mstosleep=$(( LOOPSLEEPMS_NEXTRUN - now_ms + current_time_ms_accuracy ))
153 # echo "# mstosleep is $mstosleep ms"
155 # if we are too slow, sleep some time
156 test ${mstosleep} -lt 200 && mstosleep=200
158 s=$(( mstosleep / 1000 ))
159 m=$(( mstosleep - (s * 1000) ))
160 [ "${m}" -lt 100 ] && m="0${m}"
161 [ "${m}" -lt 10 ] && m="0${m}"
163 test $tellwork -eq 1 && echo >&2 " >>> PERFORMANCE >>> WORK TOOK ${LOOPSLEEPMS_LASTWORK} ms ( $((LOOPSLEEPMS_LASTWORK * 100 / 1000)).$((LOOPSLEEPMS_LASTWORK % 10))% cpu ) >>> SLEEPING ${mstosleep} ms"
165 # echo "# sleeping ${s}.${m}"
169 # keep the values we need
171 LOOPSLEEPMS_LASTSLEEP=$mstosleep
177 # r=$(( (RANDOM * 2000 / 32767) ))
179 # m=$((r - (s * 1000)))
180 # [ "${m}" -lt 100 ] && m="0${m}"
181 # [ "${m}" -lt 10 ] && m="0${m}"
182 # echo "${r} = ${s}.${m}"
185 # ${mysleep} ${s}.${m}
187 # # the alignment loop
188 # loopsleepms tellwork 1