Re: Plan needed for switching m68k to 32-bit alignment

On Tue, 2024-10-29 at 14:39 +1100, Finn Thain wrote:
> On Tue, 29 Oct 2024, Michael Schmitz wrote:
> 
> > On 25/10/24 22:55, Arnd Bergmann wrote:
> > 
> > > I also expect that a lot of users (of m68k kernels) are never going to 
> > > get the benefits as they are already stuck on older userspace because 
> > > of added bloat in new software releases. I assume you have better 
> > > understanding than me of what m68k hardware is commonly used these 
> > > days, and how constrained that is in practice.
> > 
> > I second that - currently bisecting to find out what makes my extremely 
> > RAM constrained m68k system fail to boot or run anything past 6.9-rc4 
> > (sysvinit, not systemd).
> > 
> 
> As cloud instances multiply, that small quantity of lost RAM gets 
> multiplied. So it appears that small systems aren't so strange, even after 
> they become unprofitable...

Yes, who doesn't know the cloud instances with 64 MB RAM. Those are today's standard.

> > Much as I appreciate Adrian's efforts to keep up with user space 
> > development, I won't be in a position to help with an ABI change.
> > 
> 
> Bloated m68k packages will continue to work -- given emulators that run 
> faster with every hardware upgrade. But how would such a distro add value?

You can easily upgrade Amigas to 256 MB or more these days. The aftermarket
provides a lot of affordable upgrades these days.

> I don't mind if Gentoo ships a separate profile for (downstream) ABI 
> experimentation, leaving the default m68k profile on the standard ABI.

The Gentoo developers will be glad to hear that you don't mind. Do you think
they need a written permission from you?

> And if Debian wants to switch ABI entirely, I won't object further, I've 
> said enough about the associated risks.
> 
> So I'll just reiterate that I'd rather see more collaboration instead -
> 
> 1) among all small systems ports, to try to alleviate Debian's package 
>    dependency problem

That dependency chain comes from upstream, not from Debian.

> 2) among all developers working on non-commercial architectures, to 
>    improve the GCC Rust frontend

GCC Rust uses parts of the upstream Rust code, so you can expect the same
problems there as well.

> 3) among all 680x0 developers interested in the NetBSD ABI

The alignment issue affects NetBSD as well.

> 4) among all users of EOL'd hardware, so that value may continue to be 
>    extracted from it (thanks to the efforts of Debian and Gentoo devs, 
>    among others).

Software will run faster with 32-bit alignment, not slower.

Adrian

-- 
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer
`. `'   Physicist
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