Markus Weissmann wrote:
So the discussion has narrowed to: 1.) disabled by default on an "per-installation" option: Can be toggled system-wide (with default "off"); ports have to actively deny a parallel build attempt;
2.) disabled by default on a per-port option Can be toggled system-wide (with default ?); ports have to actively declare to be build-able in parallel;
The point is: The primary goal when building software is working installations, everything else is of less priority. For getting the build time reduced, you get defunct software, which is a bad trade-off. Therefore even the power-user with an 8-core Xeon will rather wait a bit longer than get defunct software. So enabling parallel builds will suck, as stuff starts to break. I'd rather give them a real benefit that IF they enable parallel builds, they get working software _always_.
Therefore I think 2.) is the option of choice so everyone gets happy. The default in 2.) can be set manually or with some auto-number-of-cores detection, I dont care specifically.
Feel free to implement whatever is needed for the portfile parsing of this new toggle, I only wanted to add something a little more accessible than tweaking the build.cmd directly. If having a global default for -j is considered too dangerous, then it could be pulled from macports.conf altogether and only be available as an option. Just got tired of getting the "how do I pass -j flags over to make" question over and over... http://trac.macports.org/projects/macports/ticket/12280 --anders