On Tue, 2011-03-15 at 22:02 -0400, Andrew Henderson wrote: > > While most people don't do this, you can set your CFLAGS/CPPFLAGS > environment variables in your shell.
Gentoo does that in /etc/make.conf :) Though some packages have hard coded flags which you must remove to override. Thankfully not many, but does happen. > Autoconf configure scripts will pick > up on this and add additional flags to the base flags for your > environment. I have yet to see any software package use the "-j" flag, so > that's a safe one to override. Since "-j1" is the default, you might > suddenly find all of your new compiles after you run the configure script > again to be much snappier if you increase it. Typically on Gentoo where you see -j1 is when a package is known to fail with more than one process/parallel compile. Granted a Gentoo ebuild could only set -j1 if its set to something higher than that in make.conf, which by default is should. Most any Gentoo documentation suggests you to set -j1, to the number of cpu/cores plus one. Thus even a single core system will be set to -j2, and that could make some things fail to compile. If their build system has not be tested out and/or supports parallel compiling. > The "-j" flag specifies the number of simultaneous build processes that > are running, and multi-core CPUs will take advantage of this. So, > sometimes when you think that you are using distcc, you might actually > still be using just the cores of the local CPU if the number after the > "-j" is too small. distcc really shines when you are doing > computationally expensive compiles (high-optimization, Boost templates, > etc.). The inverse of that is if you set the -j to high, even if your not compiling on the local box. The local box might get overloaded trying to manage all the remote compiles. Its some what of a balancing act :) But on Gentoo quite a number of packages will use distcc/parallel compiles, but not all. Using distcc on Gentoo will help to speed things up, but the increase in performance is not always what one expects. -- William L. Thomson Jr. Obsidian-Studios, Inc. http://www.obsidian-studios.com --------------------------------------------------------------------- Archive http://marc.info/?l=jaxlug-list&r=1&w=2 RSS Feed http://www.mail-archive.com/[email protected]/maillist.xml Unsubscribe [email protected]
