Date: Thu, 27 Mar 2014 19:12:45 +0100 From: Jilles Tjoelker <jilles@stack.nl> To: Warner Losh <imp@bsdimp.com> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org, Dimitry Andric <dim@freebsd.org> Subject: Re: svn commit: r263778 - in head: bin lib lib/clang sbin share/mk usr.bin usr.sbin Message-ID: <20140327181245.GA69977@stack.nl> In-Reply-To: <AA90F6B0-3A7A-473D-82C2-CFDFD263E9AC@gmail.com> References: <201403262230.s2QMUdH6021943@svn.freebsd.org> <AA90F6B0-3A7A-473D-82C2-CFDFD263E9AC@gmail.com>
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On Thu, Mar 27, 2014 at 11:05:00AM -0600, Warner Losh wrote: > On Mar 26, 2014, at 4:30 PM, Dimitry Andric <dim@freebsd.org> wrote: > > Author: dim > > Date: Wed Mar 26 22:30:38 2014 > > New Revision: 263778 > > URL: http://svnweb.freebsd.org/changeset/base/263778 > > Log: > > Add a SUBDIR_PARALLEL option to bsd.subdir.mk, to allow make to process > > all the SUBDIR entries in parallel, instead of serially. Apply this > > option to a selected number of Makefiles, which can greatly speed up the > > build on multi-core machines, when using make -j. > > This can be extended to more Makefiles later on, whenever they are > > verified to work correctly with parallel building. > Why not have this ‘opt out’ rather than ‘opt in’ like it is now? Are > there any known bad dependencies this introduces? I'm paranoid about build systems ;) It is easy to add dependencies across directories and as long as directories are built in sequence, nothing goes wrong. In fact, I had enabled SUBDIR_PARALLEL in sys/modules/Makefile as well, but this caused mysterious failures with some kernels such as mips ADM5120. -- Jilles Tjoelker
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