Date: Thu, 12 Apr 2007 13:30:05 -0700 (PDT) From: youshi10@u.washington.edu To: freebsd-ports@freebsd.org Subject: Re: parallel builds revisited Message-ID: <Pine.LNX.4.43.0704121330050.22181@hymn03.u.washington.edu> In-Reply-To: <461E8CF3.3030203@gmx.de>
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On Thu, 12 Apr 2007, [LoN]Kamikaze wrote: > Benjamin Lutz wrote: >> On Thursday 12 April 2007 11:06, Garrett Cooper wrote: >>> I dunno how you want to approach this, but gmake does recommend 2 >>> jobs be run in parallel for HTT enabled chips, and 3 or 4 jobs for a >>> dual core machines. >>> -Garrett >> >> So far the approach is one job per CPU. I'll do some benchmarks lateron >> to determine wether it really helps to run more jobs. For the KDE >> ports, my gut feeling is that the improvement would be negligible. I'll >> have to evaluate non-C++ ports like gnome-*, where the compilation time >> per file is shorter. > > I find the benefit especially big with Gecko based ports like Firefox or > Thunderbird. > >> Of course, to make proper use of distcc, at least #cores + 1 jobs are >> required. I'll keep that in mind. > > The recommendation of the Distcc developers is 2 jobs per core, as long as > the machines contain sufficient memory. > > My personal experience says that it's rarely possible to divide a Makefile > into more than 6 threads. Perhaps, but that's most likely just a limitation behind gmake. With a bit of a rewrite by the devs it could better utilize lookahead and dependency mapping I would think than it currently does. Needless to say this could be an easily squashed issue for making builds go faster, particularly with the large multicore / multiprocessor machines present nowadays. -Garrett
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