I did a pass on the buildworld infrastructure and added a new features to allow SUBDIR recursions to run concurrently. This should improve buildworld -j 12 (or similar) significantly. I was able to get a 28% improvement on our quad-core (8 thread) Xeons (1075 -> 769 seconds).
This is still a bit experimental in that there may be build dependencies that we haven't ferreted out yet. In particular, you might have to update your 'install' program to the latest in master to avoid a race inside its mkdir() function which could error-out the build (only if you are doing make -j N on your buildworlds). This work cleaned up probably 70-80% of the bottlenecks we had in the buildworld. There are far fewer periods showing idle cpu during the build with these changes. http://gitweb.dragonflybsd.org/dragonfly.git/commit/d2e9c9d8664f753a0d599eceed1dd98ffa7ef479 http://gitweb.dragonflybsd.org/dragonfly.git/commit/67be553814c6242d4a801d26dc2f6e5ca4b1aa8a http://gitweb.dragonflybsd.org/dragonfly.git/commit/0e6b9ee838cf6370c2c8e3ea723839c383de96cc http://gitweb.dragonflybsd.org/dragonfly.git/commit/6e73105ec5492ebba66b83ced8a62e16f87e0498 -Matt Matthew Dillon <dil...@backplane.com>