The Linux Kernel Ready To Make TSC A Hard Requirement For x86 CPUs
Posted by anh0516@reddit | linux | View on Reddit | 28 comments
Posted by anh0516@reddit | linux | View on Reddit | 28 comments
yyg-linux@reddit
https://man.archlinux.org/man/extra/syd/syd-tsc.1.en
dosnt it already kind of do this?
anh0516@reddit (OP)
Linux 7.0 dropped support for i486, which doesn't have TSC. Linux 7.1 is dropping support for i586 CPUs that don't have TSC, such as AMD K5. Now that there are no supported CPUs which don't have TSC, TSC can be made mandatory, and in the future the logic to deal with the absence of it can be removed.
yyg-linux@reddit
/taking notes/
how many of those chips do you believe are realistically still in operation out side of hobby machines? and i wonder how many more chips will have support / systems dropped with rust adaption
anh0516@reddit (OP)
A significant amount, but 99.9% of those are running in industrial or embedded systems that either aren't running Linux, or are never having their kernel updated, so it doesn't matter if support is dropped.
k-phi@reddit
because there is no stable driver API
smallproton@reddit
Which is a good thing.
k-phi@reddit
yes, using ancient kernels is good, sure
smallproton@reddit
No. Not having a stable kernel API is better than not being able to move forward in the kernel.
Daktyl198@reddit
A stable ABI does not mean an unchanging ABI. It just means that it doesn’t change without warning. Windows and macOS manage to have stable interfaces while continuing to advance their kernel.
crazy_penguin86@reddit
No, a stable ABI is by definition unchanging. The second you change it, the compatibility is broken. Win32 gets around this with pointer and struct magic, while Apple only guarantees userspace ABI stability with swift. And for both of them, the kernels have no stable ABI.
wintrmt3@reddit
A stable kernel abi (an api wouldn't be enough) would just hinder all progress, but even if there was one no one would pay for redoing the whole verification cycle for industrial control computers, so it really wouldn't change that situation.
yyg-linux@reddit
so then..........
psaux_grep@reddit
Oldest CPU’s I own are a pair of AMD K6-II. And neither have been powered up in 19 years…
yyg-linux@reddit
Turn em on and see if they work :D Im not sure im understanding OP, hardware gets orphaned as it ages, but at that point it seems they are pretty rock solid by their cap in general computing abilities for what they can handle
CHAOSHACKER@reddit
The K5 has a TSC. I don’t know where this myth originated that it doesn’t
anh0516@reddit (OP)
Not all of them do.
CHAOSHACKER@reddit
Yes, they do. I have multiple and ran multiple
anh0516@reddit (OP)
I'll take your word for it. Regardless of whether it's correct or not, there are also a couple Cyrix 6x86 models that fall into this category of i586 without TSC, which were dropped.
CHAOSHACKER@reddit
Thats true.
What most people confuse with the K5 is the 5x86 from AMD, which is just a high clocked 486 that doesn’t support the TSC.
MatchingTurret@reddit
I wonder what that means for http://www.linux-m68k.org/
The 68060 was introduced in 1994.
anh0516@reddit (OP)
Absolutely nothing because TSC is an x86-specific feature, and m68k is not x86.
MatchingTurret@reddit
I meant the arch cleanup of 1980s CPUs.
DGolden@reddit
It's a rather obscure FPGA core mutant thing, but worth mentioning in context there is the "68080" that, in abstract ISA terms, is to m68k a bit like x86-64 is to x86. May never see incarnation as a real cpu's isa of course, just noting there's thus quite recent if completely unofficial post-68060 m68k stuff in corners of the Amiga world.
http://www.apollo-core.com/index.htm?page=coding&tl=1
anh0516@reddit (OP)
It will be dropped when there aren't enough people who both need to run a current kernel on m68k and are willing to maintain support.
amarao_san@reddit
I think, obscure architectures are safer than mainstream from rapid removal.
People do not want to have ai vibed coded exploits against antique parts of production architectures.
Mk68 is an elusive joe.
Ok_Programmer_4449@reddit
This is why you run netbsd on old hardware rather than Linux.
ColbieSterling@reddit
It's not like old kernels are disappearing from the internet. I can't imagine the lack of support for legacy CPUs going forward is much of a problem.
DDOSBreakfast@reddit
Looks like AMD Geode's could be next and are orphaned which are quite a bit more modern.
I still use one for a specific low power task. Far more powerful hardware is thrown out all the time and I got it from a garbage pile in the first place.
https://www.phoronix.com/news/AMD-Geode-Orphaned-By-Linux