Launchpad builders - increasing memory spec

[Matthias Klose]

On 04.07.2017 22:22, Steve Langasek wrote:
> Hi James,
> 
> On Tue, Jul 04, 2017 at 04:31:32PM +0000, James Page wrote:
>> Hi All
> 
>> Mathias and I where discussing some challenges around fitting the Ceph
>> build with any level of parallelism in to a virtualized launchpad builder
>> (as used for the majority of architectures today).
> 
>> Basically the current memory spec only permits a max-parallel of 2 (on
>> Xenial amd64).  Ceph is a big C++ project so takes some time to build with
>> such a low level of parallelism.
> 
>> Would it be possible to nudge up the default memory allocation on the
>> builders? I use a 16G machine for test builds of i386/amd64 and I've not
>> seen any memory exhaustion with parallel=8.
> 
>> Or maybe have a mechanism to allow a source package to request a higher
>> spec of builder?
> 
> You should probably consult the Launchpad team on this, since the Launchpad
> builder configuration is owned by them and not by the Ubuntu developers
> directly.
> 
> As far as raising the default memory allocation, understand that there is a
> tradeoff between being able to parallelize /within/ a build and being able
> to parallelize across /all/ builds.  If the sole justification for this
> request is that it would speed up the build of one particular package, I
> don't think that's a sufficient reason to reduce the capacity of the
> launchpad build farm as a whole.

no, it's not that much about the build time, but people spending time to
identify and fix / work around these issues.

> Providing a mechanism to request a builder of a different size seems ok, but
> would need to be designed/implemented in Launchpad; and how do you prevent
> this from being abused?

the autopkg test setup has two configurations for that, defaulting to the small
setup, and choosing a bigger setup on a per package basis.