parallelize whack book border array processes

lets contend i have loop bash:

for foo `some-command`
do
   do-something $foo
done

do-something cpu organization i have good glossy 4 core processor. i'd means run adult 4 do-something's during once.

the genuine proceed seems be:

for foo `some-command`
do
   do-something $foo &
done

this run all do-somethings during once, nonetheless there integrate downsides, especially do-something competence also have touching i/o behaving all during once competence delayed down bit. problem formula retard advantage immediately, proceed work do-somethings finished.

how loop there always x do-somethings controlling during once?