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Linus Torvalds: Don't Hide Rust in Linux Kernel; Death to AVX-512

posted by martyb on Monday July 13 2020, @08:41PM   

takyon writes:

Linus Torvalds' Initial Comment On Rust Code Prospects Within The Linux Kernel

Kernel developers appear to be eager to debate the merits of potentially allowing Rust code within the Linux kernel. Linus Torvalds himself has made some initial remarks on the topic ahead of the Linux Plumbers 2020 conference where the matter will be discussed at length.

[...] Linus Torvalds chimed in though with his own opinion on the matter. Linus commented that he would like it to be effectively enabled by default to ensure there is widespread testing and not any isolated usage where developers then may do "crazy" things. He isn't calling for Rust to be a requirement for the kernel but rather if the Rust compiler is detected on the system, Kconfig would enable the Rust support and go ahead in building any hypothetical Rust kernel code in order to see it's properly built at least.

Linus Torvalds Wishes Intel's AVX-512 A Painful Death

According to a mailing list post spotted by Phoronix, Linux creator Linus Torvalds has shared his strong views on the AVX-512 instruction set. The discussion arose as a result of recent news that Intel's upcoming Alder Lake processors reportedly lack support for AVX-512.

Torvalds' advice to Intel is to focus on things that matter instead of wasting resources on new instruction sets, like AVX-512, that he feels aren't beneficial outside the HPC market.

Related: Rust 1.0 Finally Released!
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AVX-512: A "Hidden Gem"?
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Original Submission

• what. what. (Score: 1, Funny) by Anonymous Coward on Monday July 13 2020, @08:51PM (5 children)

  by Anonymous Coward on Monday July 13 2020, @08:51PM (#1020672)

  "The discussion arose as a result of recent news that Intel's upcoming Alder Lake processors reportedly lack support for AVX-512."

  I don't get it. Intel is dropping AVX-512 in their upcoming processor and everyone is complaining that AVX-512 shouldn't be included and it's a waste of space.

  If that went over your head...

  Democrats won the election, but Democrats are complaining a Democrat won the election.

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• Re:what. (Score: 0) by Anonymous Coward on Monday July 13 2020, @09:02PM

  by Anonymous Coward on Monday July 13 2020, @09:02PM (#1020684)

  I hope AVX512 dies a painful death, and that Intel starts fixing real problems instead of trying to create magic instructions to then create benchmarks that they can look good on.

  I hope Intel gets back to basics: gets their process working again, and concentrate more on regular code that isn't HPC or some other pointless special case.

  I've said this before, and I'll say it again: in the heyday of x86, when Intel was laughing all the way to the bank and killing all their competition, absolutely everybody else did better than Intel on FP loads. Intel's FP performance sucked (relatively speaking), and it matter not one iota.

  Because absolutely nobody cares outside of benchmarks.

  The same is largely true of AVX512 now - and in the future. Yes, you can find things that care. No, those things don't sell machines in the big picture.

  And AVX512 has real downsides. I'd much rather see that transistor budget used on other things that are much more relevant. Even if it's still FP math (in the GPU, rather than AVX512). Or just give me more cores (with good single-thread performance, but without the garbage like AVX512) like AMD did.

  I want my power limits to be reached with regular integer code, not with some AVX512 power virus that takes away top frequency (because people ended up using it for memcpy!) and takes away cores (because those useless garbage units take up space).

  Yes, yes, I'm biased. I absolutely destest FP benchmarks, and I realize other people care deeply. I just think AVX512 is exactly the wrong thing to do. It's a pet peeve of mine. It's a prime example of something Intel has done wrong, partly by just increasing the fragmentation of the market.

  Stop with the special-case garbage, and make all the core common stuff that everybody cares about run as well as you humanly can. Then do a FPU that is barely good enough on the side, and people will be happy. AVX2 is much more than enough.

  Yeah, I'm grumpy.

  Linus

  Parent

• Re:what. Re:what. (Score: 1, Insightful) by Anonymous Coward on Monday July 13 2020, @09:58PM (3 children)

  by Anonymous Coward on Monday July 13 2020, @09:58PM (#1020752)

  It's crap because it's an instruction set for only some intel processors, which even intel is not including in all their processors, which only makes it even useless than it already is. So a waste of resources for pretty much every which way.

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  • Re:what. (Score: 2) by driverless on Tuesday July 14 2020, @03:02AM

    by driverless (4770) on Tuesday July 14 2020, @03:02AM (#1020992)

    Makes Intel look good on specific benchmarks though.

    Parent

  • Re:what. Re:what. (Score: 1) by petecox on Tuesday July 14 2020, @03:08AM (1 child)

    by petecox (3228) on Tuesday July 14 2020, @03:08AM (#1020997)

    I use a package-based distribution, so yes, I probably wouldn't see any benefit.

    Some use to Gentoo's user base who compile every optimisation for every piece of software on their machines!

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    • Re:what. (Score: 0) by Anonymous Coward on Tuesday July 14 2020, @04:43AM

      by Anonymous Coward on Tuesday July 14 2020, @04:43AM (#1021051)

      AVX-512 is only a benefit in really specific circumstances. Other than those, it hurts performance and can hurt it quite badly. One of the biggest reasons why is that in order for AVX-512 to work, the entire CPU is clocked down, slowing all other threads on that chip for the duration of that part of the pipeline.

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