Hello, I have been benchmarking my full disk encryption setup using the phoronix-test-suite. I have been noticing poor performance. When I check my dmesg, I see the following message: AVX2 instructions are not detected. I checked /proc/cpuinfo and avx2 is clearly listed in the CPU features. Has anyone else seen this or know what is causing it? I am using a 5800X on a Gigabyte X570S Aorus Master and Arch linux with the default kernel (6.4.12-arch1-1).
Looking at the benchmark results on the site I’m going to guess that PTS have compile flags hardcoded.
It’s possible, but it also happens when I use the cryptsetup benchmark. I also was getting much higher performance in the same benchmarks earlier in the year.
see if there are any cpu mitigations enabled in your o.s
you know for stuff like spectre and meltdown.
some of the newer ones (inception/downfall) may also have been patched and they have a significant hit on performance.
as you can see as of the 8th of august there has been a few disclosures.
so your o.s may be the reason if its up to date…
as to how to disable the mitigations… you will have to dig into that yourself.
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