If I run a build of packages with poudriere via something like: poudriere bulk -j testjail -J2 www/firefox the build of firefox will determine how many CPUs the buildhost actually has and use that many, e.g. on my host kern.smp.cpus == 8, so the build of www/firefox is invoked with gmake -j8
Looks like a change to the mk files has made this much happier now.