On Mon, Dec 05, 2022 at 10:54:09AM +0100, Thomas Zimmermann wrote:
Hi,
I don't have a strong opinion on this topic, but after the long discussion about using old systems, I wondered if we could get an idea about the number of users with then-obsolete machines.
I couldn't find information about x86 CPU market share so I looked at Windows releases instead. Statcounter has information on that. [1] The worldwide stats looks something like this:
Win11: ~16%; Win10: ~70%; Win8.x: ~3.5%; Win7: ~10%; WinXP: ~0.5%
There's no clear connection between Windows releases and CPUs, so the metric is somewhat fuzzy. According to Wikipedia, Windows 7 was first released in 2009 and Windows 8 in 2012. x86-64-v2 was also released in 2009, but wasn't present in AMD CPUs until 2013.
Assuming that Windows 7 systems don't support -v2, but Windows 8 systems do, Nope. From the available information Windows require cx16 since 8.1, not v2. around 10% of _possible_ would not be supported by dropping pre-v2. That might be worth the performance/feature gains or not; IDK.
Windows 10 and -v3 were both first released in 2015. It's much less clear what the impact would be. Win 11 requires it, so at least 16% of the possible users could use it. On pre-Windows 10 systems, -v3 is probably not supported. And for Windows 10 systems, IDK.
BTW it's worth to look at the regional stats for Windows usage. Africa and South America still have higher usage of older Windows releases, but only by a few percent. Interestingly Windows 7 still has a marketshare of ~23% in India.
I guess this has been discussed already, but could '-v2' support be provided for selected packages only, while the default packages would remain at -v1?
We don't have infra for that in rpm although the linker can do this at this coarse granularity. Unfortunately, these -vn feature bags aren't in any way related to real needs of software so it would be better if the actual CPU features were supported rather than these arbitrary bags. Support for that exists only as dynamic cpu dispatch inside the software in question or building software with optimizations tayloerd for your system. I think even defining these feature bags sidetracked developers from designing a real solution to the cpu feature problem. Thanks Michal