On 28.10.2007, at 23:52, js wrote:
On 10/29/07, Anders F Björklund <[EMAIL PROTECTED]> wrote:
Note that some ports will fail to build, when using "make -j 2"
What causes the build erorr? is it for bad Makefile or problem of
"-j"
option itself?
Bad makefiles, usually missing dependencies.
So, in a way, using -j encourage us to find wrong makefiles:)
Well, if you're lucky -- parallel builds get non-deterministic, so
software _may_ build correctly.
You may (!) even end up with a successful build that created "bad"
installations with misbehaving software;
An intermediate step that makes changes to a file may get scheduled
after the last step compiles an object file from this file; this way
you might get a successful build but w/o the changes from step 2.
Those are extremely hard to trace bugs and maintainers might reject
bug reports if builds got made parallel this way -- after all they
cannot reproduce failing builds due to the non-determinism.
I'd rather encourage a mechanism for port that provides a mechanism
for port authors to know how many processors there are and to enable
parallel builds if they know this to work.
Perhaps a switch "use_parallel_build [yes|no]" that will add "-j
2*CPUS" to build.args.
-Markus
---
Markus W. Weissmann
http://www.mweissmann.de/
_______________________________________________
macports-dev mailing list
macports-dev@lists.macosforge.org
http://lists.macosforge.org/mailman/listinfo/macports-dev
