Why are Ryzen 7000 series seeing more performance with security mitigation enabled

According to a Tom’s Hardware article based on finds from Phoronix According to a report by Phoronix, Ryzen 7000 processors are for some reason running faster with security mitigations enabled vs. disabled in the new Linux version 6.0. Nobody knows why this anomaly exists in AMD’s Zen 4 architecture. Still, as a result of the discovery, it is recommended to keep all relevant security mitigations enabled in Linux by default. I thought the Phoronix finding was exciting and wondered why this could be possible. Tom’s Hardware article says nobody knows why Phoronix findings are happening, and I thought it would be attractive to theorize why Phoronix is getting the results it is getting. Since I don’t have a computer science degree, I would like to hear what other forum members think is the reason for Phoronix’s results. After we receive some guesses, I will create a poll to show which theory is the most likely.

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Come on, people, give me your best guess.

My best guess ?!?

Because, Reasons :stuck_out_tongue:

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Turns out this is actually just a bug.

The mitigations off are offnin software but on in hardware. Bug in the kernel. Fix submitted upstream.

Has to do with how registers are set within the cpu.


There we go, thanks Wendell, does seem strange that security mitigations would boost performance ?!?

AMD optimised the new arch to run those code paths quickly.

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Thanks for answering my question. As usual, @wendell came to the rescue; if I weren’t so behind In my Tech reading, I would probably find the answer myself. I thought Phoronix’s results were strange. My guess was either some mistake in Phoronix’s testing or a software bug. I guess there isn’t any need for a poll. I will leave this thread open if others would like to speculate other reasons why Phoronix had the results it did.