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 current_time_ms_from_date() {
17 if [ $LOOPSLEEPMS_HIGHRES -eq 0 ]
19 now_ms="$($LOOPSLEEP_DATE +'%s')000"
21 now_ms="$(( $( $LOOPSLEEP_DATE +'%s * 1000 + %-N / 1000000' ) ))"
25 # -----------------------------------------------------------------------------
26 # use /proc/uptime as a high resolution timer
28 current_time_ms_from_date
29 current_time_ms_from_uptime_started="${now_ms}"
30 current_time_ms_from_uptime_last="${now_ms}"
31 current_time_ms_from_uptime_first=0
32 current_time_ms_from_uptime() {
33 local up rest arr=() n
35 read up rest </proc/uptime
38 echo >&2 "$0: Cannot read /proc/uptime - falling back to current_time_ms_from_date()."
39 current_time_ms="current_time_ms_from_date"
40 current_time_ms_from_date
41 current_time_ms_accuracy=1
47 if [ ${#arr[1]} -lt 1 ]
50 elif [ ${#arr[1]} -lt 2 ]
52 n="${arr[0]}${arr[1]}00"
53 elif [ ${#arr[1]} -lt 3 ]
55 n="${arr[0]}${arr[1]}0"
57 n="${arr[0]}${arr[1]}"
60 now_ms=$((current_time_ms_from_uptime_started - current_time_ms_from_uptime_first + n))
62 if [ "${now_ms}" -lt "${current_time_ms_from_uptime_last}" ]
64 echo >&2 "$0: Cannot use current_time_ms_from_uptime() - new time ${now_ms} is older than the last ${current_time_ms_from_uptime_last} - falling back to current_time_ms_from_date()."
65 current_time_ms="current_time_ms_from_date"
66 current_time_ms_from_date
67 current_time_ms_accuracy=1
70 current_time_ms_from_uptime_last="${now_ms}"
72 current_time_ms_from_uptime
73 current_time_ms_from_uptime_first="$((now_ms - current_time_ms_from_uptime_started))"
74 current_time_ms_from_uptime_last="${current_time_ms_from_uptime_first}"
75 current_time_ms="current_time_ms_from_uptime"
76 current_time_ms_accuracy=10
77 if [ "${current_time_ms_from_uptime_first}" -eq 0 ]
79 echo >&2 "$0: Invalid setup for current_time_ms_from_uptime() - falling back to current_time_ms_from_date()."
80 current_time_ms="current_time_ms_from_date"
81 current_time_ms_accuracy=1
84 # -----------------------------------------------------------------------------
85 # use read with timeout for sleep
87 mysleep="mysleep_read"
89 mysleep_fifo="${NETDATA_CACHE_DIR-/tmp}/.netdata_bash_sleep_timer_fifo"
90 [ ! -e "${mysleep_fifo}" ] && mkfifo "${mysleep_fifo}"
91 [ ! -e "${mysleep_fifo}" ] && mysleep="sleep"
94 read -t "${1}" <>"${mysleep_fifo}"
98 echo >&2 "$0: Cannot use read for sleeping (return code ${ret})."
105 # -----------------------------------------------------------------------------
106 # this function is used to sleep a fraction of a second
107 # it calculates the difference between every time is called
108 # and tries to align the sleep time to give you exactly the
111 LOOPSLEEPMS_LASTRUN=0
112 LOOPSLEEPMS_NEXTRUN=0
113 LOOPSLEEPMS_LASTSLEEP=0
114 LOOPSLEEPMS_LASTWORK=0
117 local tellwork=0 t="${1}" div s m now mstosleep
119 if [ "${t}" = "tellwork" ]
126 # $t = the time in seconds to wait
128 # if high resolution is not supported
129 # just sleep the time requested, in seconds
130 if [ ${LOOPSLEEPMS_HIGHRES} -eq 0 ]
136 # get the current time, in ms in ${now_ms}
139 # calculate ms since last run
140 [ ${LOOPSLEEPMS_LASTRUN} -gt 0 ] && \
141 LOOPSLEEPMS_LASTWORK=$((now_ms - LOOPSLEEPMS_LASTRUN - LOOPSLEEPMS_LASTSLEEP))
142 # echo "# last loop's work took $LOOPSLEEPMS_LASTWORK ms"
145 LOOPSLEEPMS_LASTRUN=${now_ms}
147 # calculate the next run
148 LOOPSLEEPMS_NEXTRUN=$(( ( now_ms - ( now_ms % ( t * 1000 ) ) ) + ( t * 1000 ) ))
150 # calculate ms to sleep
151 mstosleep=$(( LOOPSLEEPMS_NEXTRUN - now_ms + current_time_ms_accuracy ))
152 # echo "# mstosleep is $mstosleep ms"
154 # if we are too slow, sleep some time
155 test ${mstosleep} -lt 200 && mstosleep=200
157 s=$(( mstosleep / 1000 ))
158 m=$(( mstosleep - (s * 1000) ))
159 [ "${m}" -lt 100 ] && m="0${m}"
160 [ "${m}" -lt 10 ] && m="0${m}"
162 test $tellwork -eq 1 && echo >&2 " >>> PERFORMANCE >>> WORK TOOK ${LOOPSLEEPMS_LASTWORK} ms ( $((LOOPSLEEPMS_LASTWORK * 100 / 1000)).$((LOOPSLEEPMS_LASTWORK % 10))% cpu ) >>> SLEEPING ${mstosleep} ms"
164 # echo "# sleeping ${s}.${m}"
168 # keep the values we need
170 LOOPSLEEPMS_LASTSLEEP=$mstosleep
176 # r=$(( (RANDOM * 2000 / 32767) ))
178 # m=$((r - (s * 1000)))
179 # [ "${m}" -lt 100 ] && m="0${m}"
180 # [ "${m}" -lt 10 ] && m="0${m}"
181 # echo "${r} = ${s}.${m}"
184 # ${mysleep} ${s}.${m}
186 # # the alignment loop
187 # loopsleepms tellwork 1