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
12 # the time in seconds to wait, as the first argument
15 # check if high resolution timer is supported
16 if [ $LOOPSLEEPMS_HIGHRES -eq 2 ]
19 test `date +%N` = "%N" && LOOPSLEEPMS_HIGHRES=0
22 # if high resolution is not supported
23 # just sleep the time requested, in seconds
24 if [ $LOOPSLEEPMS_HIGHRES -eq 0 ]
30 # get the current time
31 local d=`date +'%s.%N'`
32 local s=`echo $d | cut -d '.' -f 1`
33 local m=`echo $d | cut -d '.' -f 2 | cut -b 1-3`
34 local now="$s$m" # milliseconds since epoch (1-1-1970)
36 # calculate required sleep in ms
39 # this is our first run
40 # just wait the requested time
41 test $LOOPSLEEPMS_LASTRUN -eq 0 && LOOPSLEEPMS_LASTRUN=$now
43 # calculate ms since last run
44 local workms=$((now - LOOPSLEEPMS_LASTRUN - LOOPSLEEPMS_LASTSLEEP))
45 # echo "# last loop's work took $workms ms"
47 # calculate ms to sleep
48 local mstosleep=$((t - workms))
49 # echo "# mstosleep is $mstosleep ms"
51 # if we are too slow, sleep some time
52 test $mstosleep -lt 100 && mstosleep=100
54 local s=$((mstosleep / 1000))
55 local m=$((mstosleep - (s * 1000)))
57 # echo "# sleeping $s.$m"
61 # keep the values we need
63 LOOPSLEEPMS_LASTRUN=$now
64 LOOPSLEEPMS_LASTSLEEP=$mstosleep