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Remember that bug with Intel Skylakes [0]? When an application used AVX, it slowed down everything else on that node. It was by far not easy to debug why some applications randomly suffered perf hits on a new hardware being rolled out in Azure.

[0] https://arxiv.org/abs/1901.04982?utm_source=chatgpt.com

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It was an early AVX-512 unit that resulted in down lock when you used more than a few instructions in short time, as well as resulted in a Linus rant.

Later CPUs (updated skylake xeons and later, AMD Zen 4 and newer) don't have the issue

Historically, it was a bit more complex than that, and applies to more than just AVX-512: https://gist.github.com/rygorous/32bc3ea8301dba09358fd2c64e0....

Fun! in Dwarf Fortress way :)

Thanks for the deeper dive

The Intel server CPUs Skylake Server, Cascade Lake and Cooper Lake, which had bad frequency/voltage management are now ancient history and very few of them have been used as workstation CPUs by individual users.

AMD Zen 4 and Zen 5, and also those Intel CPUs with AVX-512 support starting with Ice Lake, behave much better and there is no reason to avoid AVX-512, which has much better energy efficiency than the alternatives.

"Those who cannot remember the past are condemned to repeat it."

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