Re: Improving CI throughput

["Ludovic Courtès" <ludo@gnu.org>]

Hello!

Mathieu Othacehe <othacehe@gnu.org> skribis:

>> Yeah, this is a ridiculous situation.  We should do a hackathon to get
>> better monitoring of useful metrics (machine load,
>> time-of-push-to-time-to-build-completion, etc.), to clearly identify the
>> bottlenecks (crashes? inefficient protocol? scheduling issues? Cuirass
>> or offload or guix-daemon issue?), and to address as many of them as we
>> can.
>>
>> Any volunteers?  :-)
>
> I'd really like to improve the situation! A hackathon seems like a
> nice idea.
>
> As a matter of fact, I already spent some times improving the stability
> of Cuirass web interface[1].

Much appreciated!

> Now I can see multiple topics that could be approached in parallel:
>
> * Add metrics to Cuirass as you suggested. There's an open ticket about
>   that here[2].
>
> * Investigate offloading issues[3].
>
> * Fix database contention[4].
>
> * Fix guix-daemon deadlocking[5].
>
> * Monitor closely what's happening on Berlin and decide if it is
> opportune to add a build scheduler mechanism somewhere. See what Hydra
> is doing[6] and what Chris is proposing[7].

I’m happy to help tackle daemon/offload issues, but I’ll be more
motivated if others join.  :-)

> As most of the issues are only observed on Berlin machines, which access is
> restricted, we will also have to find a way to reproduce them locally.

Yeah, and these are usually non-deterministic issues and not that
frequent.

> Anyway, if some people are motivated, we could try to plan a day or
> week-end to work on those topics :).

I can try and spend some time on it this week-end.  I suggest that
people join the IRC channel and shout “CI!” as a way to rally, and then
share what they’re looking at and how they feel.  How does that sound?

Thanks for cooking up this list of issues!

Ludo’.