In >=portage-2.2_rc2 there are a few new emerge options that many Gentoo users will probably be interested in:
--jobs JOBS Specifies the number of packages to build simultaneously. Also see the related --load-average option. --keep-going Continue as much as possible after an error. When an error occurs, dependencies are recalculated for remaining packages and any with unsatisfied dependencies are automatically dropped. Also see the related --skipfirst option. --load-average LOAD Specifies that no new builds should be started if there are other builds running and the load average is at least LOAD (a floating-point number). This option is recommended for use in combination with --jobs in order to avoid excess load. See make(1) for information about analogous options that should be configured via MAKEOPTS in make.conf(5).
Here is some sample parallel build output from a catalyst stage2 build, with emerge’s new –jobs option enabled:
>>> Building (1 of 10) sys-devel/gettext-0.17 for / >>> Building (2 of 10) sys-libs/zlib-1.2.3-r1 for / >>> Building (3 of 10) virtual/libintl-0 for / >>> Building (4 of 10) dev-util/unifdef-1.20 for / >>> Installing virtual/libintl-0 to / >>> Installing dev-util/unifdef-1.20 to / >>> Building (5 of 10) sys-kernel/linux-headers-2.6.23-r3 for / >>> Installing sys-libs/zlib-1.2.3-r1 to / >>> Jobs: 3 of 10 complete, 2 running Load avg: 3.44, 1.46, 0.69