[OE-core] Suggest removing classes/siteconfig.bbclass

[Khem Raj]

On Wed, Jan 9, 2019 at 11:17 PM Robert Yang <liezhi.yang at windriver.com>
wrote:

> Hi,
>
> I reimplemented glibc's site config and did a lot of tests recently,
> finally,
> I found that it isn't as useful as I had thought, so I'm leaning to remove
> classes/siteconfig.bbclass.
>
> * Here are the test results of with/without glibc's siteconfig:
> $ bitbake recipe -cconfigure && bitbake recipe -ccleansstate && time
> bitbake
> recipe -cconfigure
> - gettext:
>      without: 2m38.382s
>      with:    2m33.099s
>
> - coreutils:
>      without: 1m19.967s
>      with:    1m13.574s
>
> - bison:
>      without: 0m56.203s
>      with:    0m50.134s
>
> These 3 recipes' do_configure are very time consuming, we can see that it
> saves
> about 6s for bison/coreutils/gettext's do_configure, but they need depend
> on
> glibc's site config recipe (glibc-site.bb), while glibc-site requires
> about 30s
> to build, so if we count glibc-site's 30s, it seems not worth. And I also
> tested
> again and again on core-image-minimal and core-image-sato with/without
> glibc's
> siteconfig, there is nearly no difference, about 30s in 30m (1.6%)'s
> differences, this maybe because of host rather than siteconfig. So I think
> that
> we can remove classes/siteconfig.bbclass since it is not as useful as
> expected.
>
> I've also tested remove siteconfig.bbclass (zlib and ncurses use it),
> there is
> no difference when "time bitbake core-image-minimal".
>
> The new implementation for glibc's site config is:
> - Add a recipe called glibc-site_2.28.bb, find out the top 100 used
> functions
>    and headers, and add them to site_config/funcs and site_config/headers.
> Please
>    see patches' commit message on how to find out the top 100.
>
> - Make target/nativesdk recipes depend on glibc-site when inherit
> autotools.bbclass
>
> Here are the 2 patches:
>    git://git.openembedded.org/openembedded-core-contrib rbt/glibc-site
>
> http://cgit.openembedded.org/openembedded-core-contrib/log/?h=rbt/glibc-site
>
>
> Please feel free to give your comments, and I will remove it if no
> objections.
>

I think if we cache all values then It probably will be faster but partial
caching will give results like you see what will be interring to see is
world build time differences when doing build from scratch
But it indeed sounds a over optimization

>
> --
> Thanks
>
> Robert
> --
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> Openembedded-core at lists.openembedded.org
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>
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