Sunday, July 12th 2020
Linus Torvalds Finds AVX-512 an Intel Gimmick to Invent and Win at Benchmarks
"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." These were the words of Linux and Git creator Linus Torvalds in a mailing list, expressing his displeasure over "Alder Lake" lacking AVX-512. Torvalds also cautioned against placing too much weightage on floating-point performance benchmarks, particularly those that take advantage of exotic new instruction sets that have a fragmented and varied implementation across product lines.
"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." Torvalds believes AVX2 is "more than enough" thanks to its proliferation, but advocated that processor manufacturers design better FPUs for their core designs so they don't have to rely on instruction set-level optimization to eke out performance."Yes, yes, I'm biased. I absolutely detest 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," he added. Torvalds recently upgraded to an AMD Ryzen Threadripper for his main work machine.
"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." Torvalds believes AVX2 is "more than enough" thanks to its proliferation, but advocated that processor manufacturers design better FPUs for their core designs so they don't have to rely on instruction set-level optimization to eke out performance."Yes, yes, I'm biased. I absolutely detest 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," he added. Torvalds recently upgraded to an AMD Ryzen Threadripper for his main work machine.