2016-07-20 19:47, Wiles, Keith: > On Jul 20, 2016, at 12:48 PM, Neil Horman <nhorman at redhat.com> wrote: > > On Wed, Jul 20, 2016 at 07:40:49PM +0200, Thomas Monjalon wrote: > >> 2016-07-20 13:09, Neil Horman: > >>> From: Neil Horman <nhorman at redhat.com> > >>> +if [ -z "$MAKE_JOBS" ] > >>> +then > >>> + # This counts the number of cpus on the system > >>> + MAKE_JOBS=`lscpu -p=cpu | grep -v "#" | wc -l` > >>> +fi > >> > >> Is lscpu common enough? > >> > > I'm not sure how to answer that. lscpu is part of the util-linux package, > > which > > is part of any base install. Theres a variant for BSD, but I'm not sure how > > common it is there. > > Neil > > > >> Another acceptable default would be just "-j" without any number. > >> It would make the number of jobs unlimited. > > I think the best is just use -j as it tries to use the correct number of jobs > based on the number of cores, right?
No Keith, -j alone use as much jobs as it can create, i.e. much more than the number of CPUs. I have no measure but I remember it is less efficient than giving a number based on available CPUs (with a multiply factor to avoid idling between jobs). For a default value, both approaches are fine.
