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On Wed, Nov 22, 2017 at 07:52:54AM +0100, Raffaele Belardi wrote: |
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> Hi, |
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> |
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> rebuilding system and world with gcc-7.2.0 on a 6-core AMD CPU I have the impression that |
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> most of the ebuilds limit parallel builds to 1, 2 or 3 threads. I'm aware it is only an |
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> impression, I did not spend the night monitoring the process, but nevertheless every time |
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> I checked the load was very low. |
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|
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multi-core is definitely worth it. Any non-trivial package |
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(wine,glibc,gcc,llvm,qt off the top of my head) will spend a long time |
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building many files that can be built in parallel with multiple make jobs. |
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|
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That being said: if you do a world rebuild you will have lots of packages |
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that spend ~40 seconds doing their autoconf run, only to build 2-3 sources |
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files. On an 8-core machine at work, I get good results using parallel |
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emerge jobs (emerge -jX). For your 6-core AMD CPU (assuming it actually |
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has 12 threads) I'd start with 'emerge -j3' and MAKEOPTS='-j12 -l16'. |
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That should get you a nice speedup, but may require a bit more ram. |