Date: Thu, 27 Mar 2014 10:41:01 -0400 From: John Baldwin <jhb@freebsd.org> To: Dimitry Andric <dim@freebsd.org> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r263778 - in head: bin lib lib/clang sbin share/mk usr.bin usr.sbin Message-ID: <201403271041.01760.jhb@freebsd.org> In-Reply-To: <201403262230.s2QMUdH6021943@svn.freebsd.org> References: <201403262230.s2QMUdH6021943@svn.freebsd.org>
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On Wednesday, March 26, 2014 6:30:39 pm Dimitry Andric 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. > > I tested this on a 24-core machine, with make -j48 buildworld (N = 6): > > before stddev after stddev > ======= ====== ======= ====== > real time 1741.1 16.5 959.8 2.7 > user time 12468.7 16.4 14393.0 16.8 > sys time 1825.0 54.8 2110.6 22.8 > > (user+sys)/real 8.2 17.1 > > E.g. the build was approximately 45% faster in real time. On machines > with less cores, or with lower -j settings, the speedup will not be as > impressive. But at least you can now almost max out a machine with > buildworld! > > Submitted by: jilles > MFC after: 2 weeks Nice! -- John Baldwin
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