Benchmarking The Performance Impact To AMD Inception Mitigations

[phoronix]

Phoronix: Benchmarking The Performance Impact To AMD Inception Mitigations

Last week the AMD Inception vulnerability was made public as a speculative side channel attack affecting Zen processors and different mitigation options based on the CPU generation. There wasn't too much communication around the performance implications of mitigating Inception while over the past week I have begun benchmarking the software and microcode updates on Ryzen and EPYC processors.

https://www.phoronix.com/review/amd-inception-benchmarks

[HEL88]

Nginx, PostrgeSQL ~12% degradation

MariaDB 20-40%

[V1tol]

Nginx, PostrgeSQL ~12% degradation

MariaDB 20-40%

CPU manufacturers just got a new marketing trick to sell new processors.

[Adarion]

Well, besides a few tests it seemed pretty fine, nearly no change. Quite a relief. And maybe these database things can be polished in the future for a little less decrease in performance.

[Vistaus]

Nginx, PostrgeSQL ~12% degradation

MariaDB 20-40%

Yet some people still say these regressions have hardly any impact on AMD. Now for the average end user, that might be true, but for DB users 20-40% is significant…

[cassiofb-dev]

Nginx, PostrgeSQL ~12% degradation

MariaDB 20-40%

That's some insane performance drop :/
Well, at least aws does not use amd or intel.

[Sevard]

Yet some people still say these regressions have hardly any impact on AMD. Now for the average end user, that might be true, but for DB users 20-40% is significant…

It is, but at the same time it doesn't really matter. These servers don't (or at least shouldn't) run untrusted code, so in most cases mitigations can be safely turned off.

[blackshard]

It is, but at the same time it doesn't really matter. These servers don't (or at least shouldn't) run untrusted code, so in most cases mitigations can be safely turned off.

Well, not exactly... if the server is your exclusive property, you may assume in does not run untrusted code.
But if your server runs VPSs with customer's code (ie: any cloud provider), then you're affected and should not assume that you run trusted code at all.

[jeisom]

I'd also say the code compilation hit is also significant. It may not seem like that much on a high core count epic, but on a Ryzen 6 or 8 core that could turn seconds into several minutes depending on the code base.

[Eirikr1848]

Do the vulnerabilities impact pre-Zen CPUs: or is the exploitable architectural component missing in those?