[Buildroot] howto incorporate buildroot into an autobuild

[Arnout Vandecappelle <arnout@mind.be>]

On 13/11/12 09:45, Thomas Petazzoni wrote:
> Hello John,
>
> On Mon, 12 Nov 2012 16:47:29 -0800, John Stile wrote:
>> I am using buildroot for an embedded Arm project.
>>
>> I was wondering how people using buildroot implement continuous
>> integration builds?
>>
>> Do you start from a clean checkout, build the whole tool chain (which
>> takes a long time), and then build the project specific stuff?
>>
>> I worry about not starting from a clean checkout, since some options may
>> change, and the tools won't be rebuilt.
>>
>> But I also worry people will complain how long the build takes.
>>
>> Is there a good strategy to balance these concerns?
>
> If you do continuous integration builds, do you really care that much
> about the build time? Even if the build takes an hour, it is still very
> reasonable for an continuous integration build system.

  If you take the approach of e.g. Qt and require *every* patch to pass an
individual CI run before its accepted, then an hour is not acceptable...

> Tips to reduce the build time:
>
>   * Get a fast machine. Many people complaining about build time are
>     building inside a virtual machine on a slow laptop. This simply
>     cannot work. Get a 4 or 8 cores machine, with 16+ GB of RAM, and
>     some good I/Os.

  I don't know...  Buildroot currently serializes a lot (cfr. Avery's
remark), so going beyond 2 cores will not help that much.  It's better
to have several machines (or a single big machine) that do different
CI builds in parallel.

>   * Use an external toolchain.

  I.e. build only your toolchain with BR2_HOST_DIR set to a different path,
and use that path as an external toolchain in future builds.


  * Staggered builds. Assuming most commits are in your own software, you
can usually define a base layer that usually doesn't change.  Do a build
of this base layer once and reuse it for later builds.  Of course, you still
need to do full, clean builds occasionally.



  Regards,
  Arnout

-- 
Arnout Vandecappelle                               arnout at mind be
Senior Embedded Software Architect                 +32-16-286540
Essensium/Mind                                     http://www.mind.be
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