The output of portage with --quite-build=y already shows system load. Nice bonus feature would be per-package build times: Current: >>> Starting parallel fetch >>> Emerging (1 of 10) sys-devel/bison-2.4.3 >>> Installing (1 of 10) sys-devel/bison-2.4.3 Proposed: >>> Starting parallel fetch >>> Emerging (1 of 10) sys-devel/bison-2.4.3, took 47 seconds >>> Installing (1 of 10) sys-devel/bison-2.4.3, took 4 seconds