Re: Guix Day: Notes from the CI session

[Leo Famulari]

On Mon, Feb 08, 2021 at 06:07:25PM +0100, Ludovic Courtès wrote:
> ## Open issue: new machines
> 
>   - fast ARM servers available
>   - criteria for hardware?
>     - must run free system (stock Guix System)
>   - hosting?
>     - the MDC (in Berlin) wouldn't host Guix-specific non-x86 servers
>     - could rent space (currently renting space for bayfront.guix in 
> Bordeaux, France), but it's relatively costly
>     - workstations could be in people's homes
>       - https://store.avantek.co.uk/ampere-altra-64bit-arm-workstation.html
>         - (benchmark info: 
> https://www.phoronix.com/scan.php?page=article&item=ampere-altra-q80 - 
> compete with AMD Epyc 7nm 2nd Gen)
>       - 
>     - small boards are unreliable or too slow
>     - looking for volunteers to help
>       - pick hardware we could buy
>       - get in touch on `guix-devel` or `guix-sysadmin` (private) mailing 
> lists

I think the status quo of 64-bit ARM for us is untenable. The emulated
builds cause mass failures that can't be reproduced on real hardware.
There is a growing demand for this platform among hobbyists and hackers
who we could convert to Guix contributors!

Regarding hosting, I heard objections to spending significant amounts of
money on it. But, there was also an objection to hosting the machines in
people's homes. Do we know anyone who could donate some rackspace? Or
office-space, if we acquire workstations instead of servers?

As for the hardware itself, yes, it's expensive, but not any more than
what we'd pay for our x86_64 build farm (~1500 CPU cores and terabytes
of RAM). Again, do we know anyone who would donate some? Should we try
negotiating a discount with vendors?

I don't think that using hobbyist SBCs is viable.  It doesn't work for
our armhf platform. Not to mention, the most powerful ones available are
merely dual-core old Cortex-A72 design. For purchasing build farm
hardware, we should look for Cortex-A76, at least, if not Neoverse N1.
Hobbyist SBCs are designed for low-power consumption, not performance;
they are basically re-using SOCs designed for TV boxes and embedded
applications.