Russ Allbery a écrit : > Aurelien Jarno <[EMAIL PROTECTED]> writes: >> Russ Allbery a écrit : > >>> The effect of dpkg-buildpackage -j is to set DEB_BUILD_OPTIONS. The >>> package should continue to look at DEB_BUILD_OPTIONS to determine >>> whether parallel builds should be done. > >> As far as I understand, the main effect is to call debian/rules with -j, >> but it also set DEB_BUILD_OPTIONS (but I fail to see why). > > It also sets MAKEFLAGS. I'm not sure that part is a good idea, since > packages that don't anticipate this can't reject the provided MAKEFLAGS in > the case that the upstream build system doesn't support parallel builds. > Basically, this means that using dpkg-buildpackage -j isn't generally > safe. It can only be used with packages that you already know support > parallel builds. >
I think that is a problem. dpkg-buildpackage -j will be really usable when *all* packages support parallel builds. On the other hand, DEB_BUILD_OPTIONS=parallel=n was ignored by packages that have not been validated by the maintainers, and used by packages that have been tested by the maintainer. Also it was possible to use only on some parts of the build. For example the make install part is sometimes problematic, and mainly depends on I/O throughput of the machine, and not CPU. This make some problems difficult to detect, as they happen only in rare case on some machines. Unfortunately dpkg-buildpackage now looks for DEB_BUILD_OPTIONS and call debian/rules with -j and the value it founds in this environment variable. That makes DEB_BUILD_OPTIONS=parallel=n useless, as it has the same effect as dpkg-buildpackage -j. I personally think that supporting DEB_BUILD_OPTIONS=parallel=n on some packages is a first goal to achieve. Supporting this option in the 100 packages which take the longest to build would probably be a huge improvement in build time of the whole archive, while being easier than fixing all the packages in the archive. The most difficult part probably being changing the policy (sigh) as some of them already support that, but through a specific environment variable. Also a lot of packages spend most of their time in the configure script for those using autotools, and in installing/removing build-depends packages for the others. Using make -j in those cases won't help. -- .''`. Aurelien Jarno | GPG: 1024D/F1BCDB73 : :' : Debian developer | Electrical Engineer `. `' [EMAIL PROTECTED] | [EMAIL PROTECTED] `- people.debian.org/~aurel32 | www.aurel32.net -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
