Re: [gentoo-dev] Guidance on adding kernel config checks to ebuilds

[Mike Pagano <mpagano@gentoo.org>]

On 9/27/21 2:15 PM, Mike Gilbert wrote:
> On Mon, Sep 27, 2021 at 1:44 PM Robin H. Johnson <robbat2@gentoo.org> wrote:
>>
>> On Mon, Sep 27, 2021 at 01:15:10PM -0400, Mike Gilbert wrote:
>>> On Mon, Sep 27, 2021 at 12:23 PM Mike Pagano <mpagano@gentoo.org> wrote:
>>>>> Adding linux-info calls to pkg_pretend or pkg_setup causes slowdowns
>>>>> when running emerge, so we should do so only when there is a
>>>>> compensating benefit.
>>>>
>>>> Is this a significant slowdown? Do you have any numbers?
>>>
>>> Adding a check for CONFIG_PACKET to the dhcpcd ebuild adds around 7
>>> seconds of delay time to the pkg_setup and/or pkg_pretend phase on my
>>> system.
>>>
>>> That's ok if a small number of packages are doing it, but it would
>>> become quite annoying if a significant number of them get queued up.
>> 7 seconds is ridiculous.
> 
> I think the horribly slow performance is mainly due to this change in
> how we detect the kernel version:
> 
> https://gitweb.gentoo.org/repo/gentoo.git/commit/eclass/linux-info.eclass?id=d1ea596f034285cd044006b107a60902ea059793
> 
> That causes "make" to be called 4 times, and each make invocation adds
> a couple of seconds to the get_version call.
> 

Changes to these eclasses are like a prison of circular breakage for which there is no escape.