[Buildroot] Another Buildroot Enhancement Suggestion (re-use base build)

[Nimai Mahajan]

On Fri, Jul 17, 2015 at 3:04 AM, Baruch Siach <baruch at tkos.co.il> wrote:
> Hi Nimai,
>
> On Thu, Jul 16, 2015 at 08:48:02AM -0400, Nimai Mahajan wrote:
>> I should have brought this up during the hackathon but it totally
>> slipped my mind. But anyways, here it goes: we use Buildroot for ~3-4
>> projects here at work and it's been great for us since it is very easy
>> to customize and build from the ground up. We generally compile our
>> builds from scratch, as is the Buildroot norm, and that works (I also
>> use CCACHE and external toolchain and that does help quite a bit) but
>> I was wondering if this could be even further sped up.
>>
>> The use case is that our release builds for those 3-4 projects is
>> always the same (minus a slightly different fs overlay and 1-2
>> different packages). Is there any way or do you guys see any
>> usefulness in taking an already built "external base build" with all
>> the packages that subsequent builds will use and telling Buildroot
>> what to add on top of it? Basically, it doesn't make sense to me to
>> rebuild the entire thing when only a few files change. This is
>> probably a huge effort as I don't think a mechanism exists to do it
>> but I'm just looking for some comments/thoughts. Does this even make
>> sense or is there already a decent way to do this?
>>
>> For release builds, this is not a major problem because builds only
>> take 5-10 min at most, but when you're compiling debug builds with
>> debugging symbols for various projects, this can add hours or even
>> days if builds fail. We have Jenkins running and pumping out builds
>> for us 24/7, and this would help a lot in testing, taking a prebuilt
>> base build and just recompiling our custom packages (for now, we do a
>> -dirclean on our packages and rebuild them every time which works for
>> the time being).
>
> The patch at http://patchwork.ozlabs.org/patch/464753/ might be helpful for
> you. Please check it out and let us know.
>
> baruch
>
> --
>      http://baruch.siach.name/blog/                  ~. .~   Tk Open Systems
> =}------------------------------------------------ooO--U--Ooo------------{=
>    - baruch at tkos.co.il - tel: +972.2.679.5364, http://www.tkos.co.il -

Thanks, I will take a look at that. I think with that + the recently
proposed RFC here
(http://permalink.gmane.org/gmane.comp.lib.uclibc.buildroot/120702)
that highlights a "phased" build approach, I think this is definitely
doable in a reliable way. I think it depends on what will Thomas plans
to do about the custom skeleton, as the first patch seems reliant on
that.