There are plenty of people, and when i mean plenty, i mean in the thousands category, that still use Ubuntu on hardware older than 2015.
Many people switch to Linux - Specifically Ubuntu or an Ubuntu based distro, because their hardware isn’t supported by other operating systems.
So if you want to give x86-64 v3 performance improvements, you could take notes from how Tumbleweed did it. Tumbleweed installed an x86-64-3 package by default on systems that support it and it still supported older hardware.
There are still a large number of CPUs in use that do not support AVX instructions, mine included (Intel Core i7-990x). In fact, 1st generation Intel i7 chips have been recently popular for budget PC builds, as the performance of the hexa-core models overclocked can actually be quite decent.
Setting the CPU support baseline to v3 as mentioned in the blog post would be a huge mistake, IMO, and many—myself included—would have to migrate to a different Linux base if this were to happen.
I should have expected that given we didn’t say what our plans are for the future people would start to fill in the gaps a bit. But the reason we didn’t say anything about that is mostly that we haven’t decided where we’re going with this. We are literally just running some investigations!
What I can say with certainty is:
Nothing is going to change wrt the amd64 baseline in 24.04.
We are very aware of the issue of users who have hardware that can’t run v3 or even v2! Hopefully we can do something that gets the best of both worlds but like I said, no concrete plans yet.
Thanks Alan for linking to my previous comment on this. Please do not worry that we are going to abandon users of oldish hardware without at least thinking about it – I want to be clear that no decisions have been made on this and nothing is going to be happening before 24.04.
We haven’t ruled it (or anything else!) out, but we did think about this sort of thing.
It has some advantages:
it’s fairly straightforward, all the dynamic linker features are present already
it continues to support all users
it allows targeting the packages that benefit the most
But also some downsides:
it would require per-package work to enable building the optimized version of the library (though this could probably be made pretty easy)
it uses more disk space on systems that install the v3 libraries (unless there is more package manager magic going on than I realise)
you only get optimized versions of shared libraries that are loaded from the standard dynamic linker search path (so, not executables or things like Python C extensions)
The word “just” is doing a lot of lifting in that sentence. We have to make two versions of every package – how do you publish them? How do you tell which one you are looking at? How do you explain to users which ISO to download? All of these are solvable problems but it’s not easy.
That would be difficult. i can imagine askubuntu.com filled with posts about which version should they install.
The inexperienced user will just think: Oh, X86-64-V3 is what i should choose for my computer, as its obviously the better version! Then they get bamboozled when it doesn’t install. Then that newbie is going to be like: Oh. I thought this was one of the selling points of Linux: Supporting older hardware! Oh well, back to windows.
The only selling point for Canonical are servers, the Ubuntu Desktop is developed primarily with idealistic goals in mind. And Ubuntu lags behind here, since RHEL 9 (released 2022) already uses x86_64-v2 and the upcoming RHEL 10 (2025) will use x86_64-v3. And for enterprise customers every cent performance counts, because large-scale computing machines need to get the most out of their hardware.
If you get 10% more performance with x86_64-v3, you need 10% less hardware costs, 10% less servicing costs, 10% less energy costs and 10% less cooling costs. This is an important factor when deciding on a platform.
And in order for Canonical to continue to subsidise the very good Ubuntu desktop, the server business must be running, otherwise Canonical may have to reduce its investments in the Desktop.