New Linux Kernel Code Works On APIC "Decrapification", Suggests Dropping x86 32-bit

[SofS]

This 32bit x86 includes microcontrollers? Because if so Intel Quark was only discontinued in 2019. Which, by the way, is the date that should be of relevance for such discussions instead of the launch date.

Also, can anyone confirm if Hyper Threading counts for SMP? Because if so even the Pentium 4 and Atoms had it. Meanwhile the Core Duos were obviously SMP, so, if all these count as SMP, then forcing SMP would be an issue on the desktop only for the Core Solo line.

As for dates, the Core families were discontinued during 2012 and Atom I was unable to find the date from which it was discontinued, but the last 32bit only model was the Z600 launched during 2011.

[qlum]

They want to deprecate running on pure 32bit CPUs. I don't think there are more than a dozen people in the entire world using Linux 6.4.x on them.

We are talking about Pentium 4 Northwood's released in 2002 or Athlon Barton/Thorton's released in 2003. Net gen Pentiums and Athlons were already 64bit.

You cannot support old shit indefinitely or otherwise there will be people requiring Linux to fully support Intel 8086. Most modern Linux distros are x86-64 only and require at the very least 256MB of RAM just to boot in text mode. What's the point?

Unlike Michael however I don't think these changes will result in any performance improvements. On x86-64 systems the code in question is never used since it's behind #ifdef.

TBO, there's nothing to discuss here. If you have old junk and you feel nostalgic, use something from the bygone era. Modern stuff will run like molasses on it it it runs at all which is questionable.

Edit: I've totally forgotten about Intel Atoms. There are two Atoms, N270 and N280 from 2008 and 2009 respectively, that are 32bit only. Damn it, Intel. If Linus remembers about them, this patchset could be a no go for at least 5 more years.

There are also the failed tablet / mobile cpu's which were 32bit only until 2013 the Z2760 for example also landed in laptops that year.

then there is the quark which only became end of life in 2019 and was last shipped in 2022.

So yea it's gonna take a while before it can truely be removed.

[GreenReaper]

This reminds me of https://www.vortex86.com/

Okay, that's too niche. But does the mention of SMP means that future Linux will be incompatible with single core VM?

I think that it is more that there will be no support for running without SMP code, which adds ~10% overhead that is elided in uniprocessor builds. (Think of all the locks that form part of kernel structures.)

Such kernels should still work fine on uniprocessor CPUs as long as they do not assume the presence of e.g. multiprocessor ACPI tables that are not there.

As noted above, distro kernel binaries will be SMP, so if using them you pay the tax. It is possible to compile distro source with a uniprocessor config and I do that for a few of the aforementioned VMs. Doing it on actual hardware would be possible, although likely quite slow.

[Weasel]

They want to deprecate running on pure 32bit CPUs. I don't think there are more than a dozen people in the entire world using Linux 6.4.x on them.

Ah the pure ignorance of thinking everything is your desktop/laptop use case.

I suggest you look up Intel Quark and enlighten yourself once again.

[MorrisS.]

this mf literally advocating for planned obsolescence like he works for Apple

It's not matter of apple, it is matter of efficiency. Saved time in development improves the quality of software optimizing hardware. Moreover, the Cut off in the amount of software developed in 32bit reduces MB in software itself saving resources' memory.

[jrdoane]

Ah the pure ignorance of thinking everything is your desktop/laptop use case.

I suggest you look up Intel Quark and enlighten yourself once again.

People actually use that for embedded designs? I'm pretty sure there is a reason why it's EoL'ed and it's not because it was successful. Intel's own Product Notification statement says this:

Description of Change to the Customer: Market demand for the products listed in the "Products Affected/Intel Ordering Codes" table below have shifted to other Intel products. The products identified in this notification will be discontinued and unavailable for additional orders after the "Last Product Discontinuance Order Date" (see "Key Milestones" above).

That's a fancy way of saying that there wasn't enough market demand.
src: https://qdms.intel.com/dm/i.aspx/E88...N116715-00.pdf

[Adarion]

Why does an old machine needs the newest kernel?

Because of security fixes. HW support rarely improves for these machine, that's true, but the fixes would be welcome.

[Namelesswonder]

Ah the pure ignorance of thinking everything is your desktop/laptop use case.

I suggest you look up Intel Quark and enlighten yourself once again.

The most use Intel got out of Quark is using it for the Management Engine, which runs MINIX so Intel isn't shooting themselves in the foot here.

Given Intel's investments in RISC-V I am sure they will be switching the ME to run on an embedded RISC-V core sometime soon.

That leaves the only lasting success of Quark as running the spying and backdoor engine on Intel's products for the past decade, every other use of Quark was incredibly niche and already consumed by ARM before Intel was even able to get it to market.

[chithanh]

Edit: I've totally forgotten about Intel Atoms. There are two Atoms, N270 and N280 from 2008 and 2009 respectively, that are 32bit only. Damn it, Intel.

The last consumer 32-bit x86 Atom was the Z670, released in 2011.

That's a fancy way of saying that there wasn't enough market demand.

No, it is because the other products became more competitive, so people chose Atom over Quark CPUs going forward.

Also Quark is used to this day in the Intel ME, but it doesn't run Linux. Intel originally tried to make Linux work on the ME but the kernel maintainers were uncooperative, so they switched to MINIX.

[pegasus]

It's too soon for death of 32 bit...

Obviously it's time for Linux 7 64bit (only)