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