Re: GCC Buildbot Update

[Segher Boessenkool <segher@kernel.crashing.org>]

On Fri, Dec 15, 2017 at 08:42:18AM +0100, Markus Trippelsdorf wrote:
> On 2017.12.14 at 21:32 +0100, Christophe Lyon wrote:
> > On 14 December 2017 at 09:56, Paulo Matos <pmatos@linki.tools> wrote:
> > > I got an email suggesting I add some aarch64 workers so I did:
> > > 4 workers from CF (gcc113, gcc114, gcc115 and gcc116);
> > >
> > Great, I thought the CF machines were reserved for developpers.
> > Good news you could add builders on them.
> 
> I don't think this is good news at all. 
> 
> Once a buildbot runs on a CF machine it immediately becomes impossible
> to do any meaningful measurement on that machine. That is mainly because
> of the random I/O (untar, rm -fr, etc.) of the bot. As a result variance
> goes to the roof and all measurements drown in noise.

Automated runs should not use an unreasonable amount of resources (and
neither should manual runs, but the bar for automated things lies much
lower, since they are more annoying).

All the cfarm machines are shared resources.  Benchmarking on them will
not work no matter what.  And being a shared resource means all users
have to share and be mindful of others.

> So it would be good if there was a strict separation of machines used
> for bots and machines used by humans. In other words bots should only
> run on dedicated machines.

The aarch64 builds should probably not use all of gcc113..gcc116.

We do not have enough resources to dedicate machines to bots.


Segher