Re: Parallelism a la make -j <n> / GNU parallel

[John Kearney]

Am 04.05.2012 21:11, schrieb Greg Wooledge:
> On Fri, May 04, 2012 at 09:02:27PM +0200, John Kearney wrote:
>> set -m
>> cnt=0
>> trap ': $(( --cnt ))' SIGCHLD
>> set -- {0..20}
>> while [ $# -gt 0 ]; do
>>      if [[ ${cnt} -lt 10 ]] ; then
>>
>>              (
>>                      d=$(( RANDOM % 10 ))
>>                      echo $n sleeping $d
>>                      sleep $d
>>              ) &
>>              : $(( ++cnt ))
>>              shift
>>      fi
>>      echo going to wait
>>      sleep 1
>> done
> You're busy-looping with a 1-second sleep instead of using wait and the
> signal handler, which was the whole purpose of the previous example (and
> of the set -m that you kept in yours).  And $n should probably be $1 there.
>
see my response to mike.


what you are thinking about is either what I suggested or something like
this

function TestProcess_22 {
        local d=$(( RANDOM % 10 ))
        echo $1 sleeping $d
        sleep $d
        echo $1 exiting $d
}
function trap_SIGCHLD {
        echo "SIGCHLD";
        if [ $cnt -gt 0 ]; then
            : $(( --cnt ))
            TestProcess_22 $cnt  &
        fi
}
set -m
cnt=20
maxJobCnt=10
trap 'trap_SIGCHLD' SIGCHLD
for (( x=0; x<maxJobCnt ; x++ )); do
            : $(( --cnt ))
            TestProcess_22 $cnt  &
done
wait
trap - SIGCHLD