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Hi, |
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|
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On Thu, 20 Nov 2014 20:16:09 -0800 Zac Medico wrote: |
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> > There's currently no switch for this. However, you can use a a command |
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> > like this to see all installed packages that pull in your installed ghc: |
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> > |
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> > emerge -pv --depclean dev-lang/ghc |
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> > |
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> > I've filed a feature request bug for the switch that you have requested: |
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> > |
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> > https://bugs.gentoo.org/show_bug.cgi?id=529988 |
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> |
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> I forgot, we have a --verbose-conflicts option already. |
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|
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Yeah, that's exactly what I need. Somehow I missed this option, |
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sorry. |
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|
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> > From your results, it seems that _select_pkg_highest_available would be |
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> > an obvious thing to optimize. This method already uses memoization, but |
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> > the cache is entirely discarded each time that a package is added to the |
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> > graph. I will see about making it salvage as much cache as possible when |
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> > a package is added. |
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> |
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> I've written a patch, and it gives good results. On one of my computers |
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> with this patch, 'emerge -puvDN @world' takes 15% less time, and results |
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> in 58% fewer _select_pkg_highest_available_imp calls: |
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> |
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> https://bugs.gentoo.org/show_bug.cgi?id=530010 |
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|
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I've done some profiling with this both patches (from bugs 529660 |
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and 530010) applied. See *p530010*.pdf files for both hosts here: |
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ftp://brunestud.info/gentoo/portage-v4.tar.xz |
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|
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For performance enhancement I get the following data for |
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normal (that is unprofiled) runs: |
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time calls |
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desktop 13% 62% |
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hitomi 6% 62% |
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|
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where time — is % less real time for emerge run and calls stands |
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for % less _select_pkg_highest_available_imp calls. |
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|
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While testing --verbose-conflicts I found that if tree contains |
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unresolved conflict, it takes much longer time for emerge to |
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proceed: +36% on desktop and +44% on hitomi. |
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|
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Unresolved conflict was created by adding apt-text/dvipdfmx to the |
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@world: it blocks latex-2014 update. (Actually I just reverted one |
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of fixes I made earlier in order to run -DNupv @world without |
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errors .) Looks like emerge tries to build more depgraps to solves |
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this issue. I'm not sure if this may be a subject for optimization. |
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Graps are also present in the tarball in "*@world_with_blocks*.pdf" |
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files. |
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|
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And thank your for optimizations! They really give a new breath to |
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my old boxes. Awaiting for them upstream :) |
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|
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Best regards, |
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Andrew Savchenko |