Date: Mon, 16 Oct 2006 16:30:23 -0700 From: Kent Stewart <kstewart@owt.com> To: "Nikolas Britton" <nikolas.britton@gmail.com> Cc: freebsd-stable@freebsd.org Subject: Re: FreeBSD and "make -j# buildworld" usability Message-ID: <200610161630.23776.kstewart@owt.com> In-Reply-To: <ef10de9a0610161246w25652bb7ra198db6eecd25d02@mail.gmail.com> References: <20061013143130.GW491@dev.null.cz> <200610131347.41023.kstewart@owt.com> <ef10de9a0610161246w25652bb7ra198db6eecd25d02@mail.gmail.com>
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On Monday 16 October 2006 12:46, Nikolas Britton wrote: > On 10/13/06, Kent Stewart <kstewart@owt.com> wrote: > > On Friday 13 October 2006 07:31, Buki wrote: > > > Hi, > > > > > > I searched the archives and web a little but found many different > > > opinions on stability/usability of using make -j# with buildworld > > > (and buildkernel). > > > > > > So I am asking if it is a good idea to use make -j on production > > > boxes. > > > > I tested buildworlds with different values for -j. On single > > processors, using a script that basically looked like > > > > time make -j? ... > > > > yielded fastest builds when I didn't specify a value for -j. On > > dual cpu's a value around -j8 yielded the fastest build. > > That's odd, your results don't jive with this: > http://people.freebsd.org/~fsmp/SMP/akgraph-a/graph1.html His results are too old to use as a reference. My system was the next step up and is also too old to consider current. His cpus were Intel Pentium pro 200MHZ and the bus speed alone (66MHz) would make a big difference. Only having 64MB of memory may also skew the results. My system was 2 Intel pIII 866's and had 256-512MB of SDRAM or DDR memory. Kent > > Although that report is quite old... My general rule of thumb for -j > is n +1, where n equals the total number of cpu cores. This is > generally enough to keep to processor(s) occupied without over > stressing the system. Maybe n * 2 is more appropriate, can you post > the results from your test? -- Kent Stewart Richland, WA http://www.soyandina.com/ "I am Andean project". http://users.owt.com/kstewart/index.html
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