Linux Kernel Developers Discuss Dropping x32 Support

[ssokolow]

Captain here, there is no such thing as x32. Kernel developers must be silly. There's only x86, in which the x stands for various numbers of Intel processors, like the 80386 and 80486. They all end with 86, that's where the naming scheme comes from. Intel never had 80432 or anything the like, so the x32 name is very wrong. It's supposed to be 32-bit, no x involved.

If you were talking about referring to the "amd64" architecture as "x64", as the Windows ecosystem seems to, your argument would have merit.

x32 is specifically intended to be distinct from x86 and amd64 (A.K.A. x86_64) since it's a synthetic ABI that frankensteins the 32-bit pointers from protected mode into long mode's larger register set. As such, it's designed to be familiar to the x86 name without without being tied to a specific product... a relationship similar to the relationship between x32 and x86_64.

[Jonjolt]

I don't know if the JVM uses this or not but, the JVM uses compressed pointers for heap sizes under 32GB https://stackoverflow.com/questions/...ompressed-oops

[peppercats]

I don't know if the JVM uses this or not but, the JVM uses compressed pointers for heap sizes under 32GB https://stackoverflow.com/questions/...ompressed-oops

It's unrelated.

Software trick to compress pointers that are decoded when dereferenced(all behind the scenes by the JVM, of course)
pretty smart because the extra ALU ops to decode the pointer are basically free due to the (relatively) much much longer time to fetch something from memory

[wizard69]

RAM is precious ressource, x32 is important to save memory where you manipulate lot of pointer. Then mostly on optimized software.
But: most of the software is not optimized (KDE is not), in general you need choose: features or optimisation, nobody work on both.
Maintenance cost is important, disk/fs layer, GPU, network can be improved.

This really isn’t true anymore, especially for mid stream users. It takes a lot of effort to use all available memory in today’s systems and simple upgrades take care of that.

[wizard69]

Even if it made sense to compile software as x32 for performance, one of the biggest issues I see with x32 is that you need x32 versions of all libs you are depending on. 32-bit x86 is annoying enough to keep on our systems.

Supporting 32 bit software in any matter is a waste of resources in my mind. I’d really like to see the kernel drop all 32 bit support. X32 is one thing but combine that with all the other support and it ends up being a terrible waste of resources.

[wizard69]

Apparently Apple switched to a 64-bit capable iOS 7 with their A7 chip in the IPhone 5S in 2013. Currently they're apparently on the A11 chip and iOS 11, so already fourth generation 64-bit phone system.

There are also aarch64 android phones, but with the android ecosystem so fragmented, Apple makes for an easier comparison. No endorsement of Apple intended per se.

Actually Apple is on A12 or A12X which can be described as rather incredible ARM processors. The high performance Apple is getting out of ARM hardware isn’t what we should be focusing on here. Rather it is the demands they are placing on developers to have 64 bit clean code and to prepare for the end of 32 bit support.

The reason, speculation on my part, is that there are two benefits. One is the rather massive reduction in duplication often leading to massive memory usage and significant support issues. Even further speculation here is my expectation that we will shortly see a 64 bit only processor from Apple. That is they will remove all hardware support for ARMs older 32 bit instruction set. That means smaller cores, less power usage and better performance.

In any event there is considerable benefits benefits that people following this discussion should realize. Your limited RAM goes a lot farther when there is only one set of libs loaded into it. Support is far easier for everyone concerned. In any event one only has to look at how things run on iOS and the latest Apple processors to realize being focused on the past is supremely foolish.

[Jabberwocky]

No. And FYI I'm a developer. If you can't write code that can transparently deal with both, you just suck.

Please tell me more. I want to learn to solve complex low level caching and bandwidth optimization problems by writing abstract portable code.

Is Java better than x32?

[Jabberwocky]

The reason, speculation on my part, is that there are two benefits. One is the rather massive reduction in duplication often leading to massive memory usage and significant support issues. Even further speculation here is my expectation that we will shortly see a 64 bit only processor from Apple. That is they will remove all hardware support for ARMs older 32 bit instruction set. That means smaller cores, less power usage and better performance.

In any event there is considerable benefits benefits that people following this discussion should realize. Your limited RAM goes a lot farther when there is only one set of libs loaded into it. Support is far easier for everyone concerned. In any event one only has to look at how things run on iOS and the latest Apple processors to realize being focused on the past is supremely foolish.

+1 Theoretically this seems like the best way of obtaining improved performance. An advantage one has when you control the software that is used on your hardware.

[nanonyme]

Supporting 32 bit software in any matter is a waste of resources in my mind. I’d really like to see the kernel drop all 32 bit support. X32 is one thing but combine that with all the other support and it ends up being a terrible waste of resources.

That's basically telling Steam and folks to go back to Windows

[nvaert1986]

That's basically telling Steam and folks to go back to Windows

That's also what I'm thinking, but I'm not sure whether this applies to to Steam or wine, as it's for the kernel and core tools only (if I interpreted the mail archive correctly), but I'm not sure about other userspace utilities. But if that's the case, that would be a reason (force me) again to use Microsoft Windows in the future, as I'm using several 32-bit binaries using wine, which I need to perform daily tasks and are simply not available in 64-bit. That's why I asked the question whether this will apply to all 32-bit support (including wine) or not.