3 # this function is used to sleep a fraction of a second
4 # it calculates the difference between every time is called
5 # and tries to align the sleep time to give you exactly the
10 LOOPSLEEPMS_LASTSLEEP=0
11 LOOPSLEEPMS_LASTWORK=0
14 if [ "$1" = "tellwork" ]
20 # the time in seconds to wait, as the first argument
23 # check if high resolution timer is supported
24 if [ $LOOPSLEEPMS_HIGHRES -eq 2 ]
27 test `date +%N` = "%N" && LOOPSLEEPMS_HIGHRES=0
30 # if high resolution is not supported
31 # just sleep the time requested, in seconds
32 if [ $LOOPSLEEPMS_HIGHRES -eq 0 ]
38 # get the current time
39 local d=`date +'%s.%N'`
40 local s=`echo $d | cut -d '.' -f 1`
41 local m=`echo $d | cut -d '.' -f 2 | cut -b 1-3`
42 local now="$s$m" # milliseconds since epoch (1-1-1970)
44 # calculate required sleep in ms
47 # this is our first run
48 # just wait the requested time
49 test $LOOPSLEEPMS_LASTRUN -eq 0 && LOOPSLEEPMS_LASTRUN=$now
51 # calculate ms since last run
52 LOOPSLEEPMS_LASTWORK=$((now - LOOPSLEEPMS_LASTRUN - LOOPSLEEPMS_LASTSLEEP))
53 # echo "# last loop's work took $LOOPSLEEPMS_LASTWORK ms"
55 test $tellwork -eq 1 && echo >&2 " >>> PERFORMANCE >>> WORK TOOK $LOOPSLEEPMS_LASTWORK ms ( $((LOOPSLEEPMS_LASTWORK * 100 / 1000)).$((LOOPSLEEPMS_LASTWORK % 10))% cpu )"
57 # calculate ms to sleep
58 local mstosleep=$((t - LOOPSLEEPMS_LASTWORK))
59 # echo "# mstosleep is $mstosleep ms"
61 # if we are too slow, sleep some time
62 test $mstosleep -lt 100 && mstosleep=100
64 local s=$((mstosleep / 1000))
65 local m=$((mstosleep - (s * 1000)))
67 # echo "# sleeping $s.$m"
71 # keep the values we need
73 LOOPSLEEPMS_LASTRUN=$now
74 LOOPSLEEPMS_LASTSLEEP=$mstosleep