Re: bug#47615: [PATCH 0/9] Add 32-bit powerpc support

[Ludovic Courtès]

Hi Efraim,

Efraim Flashner <efraim@flashner.co.il> skribis:

> On Sat, Apr 17, 2021 at 06:04:02PM +0200, Ludovic Courtès wrote:

[...]

>>   3. OTOH, what will be the status of this architecture?  I don’t think
>>      new 32-bit PPC hardware is being made (right?), so I guess we
>>      probably won’t have substitutes for that architecture.  That means
>>      it won’t be supported at the same level as other architectures and
>>      may quickly suffer from bitrot.
>
> I don't know about new 32-bit powerpc hardware, I think it's only being
> newly created for the embedded and networking space. As far as operating
> systems with support¹ Adélie Linux is the only one I know that's
> actually targeting the machines.
>
> I found that emulation on my desktop (Ryzen 3900XT, 24 threads) is
> faster than building on native hardware (1 core, 1.5GB of RAM, original
> 4200 RPM disk), edging it out on single threaded compiling and doing
> great when it comes to using multiple cores and parallel builds.
> Ignoring how to create an OS image if we just targeted, say, mesa and
> maybe one or two other packages, we could have a core set which doesn't
> change regularly and won't take up too much emulated build time but will
> save days of compile time.

[...]

> The fear of bit-rot is real and I think we should mention in the manual
> (when I actually write the section) that support is best-effort with
> minimal substitutes.

I feel like “best-effort with minimal substitutes” is already more than
I’d be willing to commit to as a maintainer.

We just added POWER9, for which we have actual hardware, and even
getting to this minimal state where we provide a binary tarball required
quite some effort.

Doing the same with 32-bit PowerPC would require us to set up emulation;
we wouldn’t even have real hardware.

All in all, my preference would be to take the patches but not mention
PowerPC 32-bit support anywhere, or at least, not provide substitutes
and binary installation tarball.  IOW, few people would know whether it
actually works :-) but tinkerers could still play with it.

WDYT?

Ludo’.