Linux kernel creator Linus Torvalds expects to see the end of Intel’s 512-bit vector extensions and admits he has an “irrational hatred” of the floating point (FP) benchmarks used to demonstrate their value.
Torvalds criticized the instructions for the Intel Advanced Vector Extensions 512 (AVX-512) in a mailing list chat. I was responding to Phoronix’s article on the GNU Compiler Collection 11 that lacks support for AVX-512 in the compiler instructions that Intel has enabled for Alder Lake, its 2021 processors for the desktop. Future Intel Xeon Sapphire Roads processors are still compatible with AVX-512.
“I hope that the AVX-512 dies of a painful death, and that Intel begins to solve real problems instead of trying to create magical instructions and then create benchmarks where they can look good,” Torvalds wrote.
Torvalds makes an exception to Intel’s focus on FP benchmarks and the performance of its processors on supercomputers or high-performance computers (HPCs)
“I hope Intel gets back to basics: Get your process working again and focus more on regular non-HPC code or some other special nonsense case.”
He notes that “at the height of x86,” Intel’s rivals always outperformed it in FP loads.
“Intel’s FP performance was a failure (relatively speaking), and it doesn’t matter a bit. Because nobody cares beyond benchmarks,” said Torvalds.
“The same goes a lot with AVX-512 now, and in the future. Yes, you can find things that matter to you. No, those things don’t generally sell machines.”
He continued his criticism saying that AVX512 has real downsides.
“I.D much rather, to see that the transistor budget is used in other things that are much more relevant. Even if it is still math FP (on the GPU, instead of AVX-512). Or just give me more cores (good single-thread performance, but no garbage like AVX-512) like AMD did. ”
Web performance company Cloudflare has written about the performance impact of AVX-512. Advised clients who do not need AVX-512 for high performance tasks to disable AVX-512 running on server and desktop to avoid “accidental” bottleneck.
“I want my power limits to be reached with a regular integer code, not an AVX-512 power virus that removes the maximum frequency (because people ended up using it for memcpy!) And removes cores (because those useless garbage units take up space), “Torvalds continued.
“Yes, yes, I’m biased. I absolutely loathe FP benchmarks, and I realize that other people care deeply. I just think AVX-512 is exactly what I shouldn’t do. It’s a hobby of mine. It’s a A prime example of something Intel has done wrong, in part by increasing market fragmentation.
“Stop with the special case trash and do all the core common things that everyone he cares about running as well as humanly. “
In another email, Torvalds emphasized that he had an “irrational hatred of vector units and FP benchmarks.”
“I think they are largely a total waste of transistors and effort, and I think the amount of time they spend on them, both from hardware people and from software people trying to use them, has been largely wasted.” , wrote.
“So I’m exaggerating and exaggerating things to the point of joking. But only half. I’m taking a pretty extreme point of view, and I know that my hatred is not really rational, but just a personal quirk and purely unadulterated rant. “
Linus Torvalds: “I hope the AVX-512 dies of a painful death and that Intel begins to solve real problems.”
Image: Linus Torvalds / TED / YouTube
