Do you think it is safe and secure to disable Mitigation in Fedora for the sake of performance?

3 years ago by Harry_Houdini to c/linux

I've seen a video from CTT demonstrating the <10 performance boosts by simply off the mitigation. The system will be secure for personal use as before.

SuperFola 45 points 3 years ago

Ask yourself: do you really need a performance boost or are you just chasing the numbers to avoid a non-existant problem?

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OsrsNeedsF2P 3 points 3 years ago

Yea

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db2 31 points 3 years ago

Everything is secure until it isn't. I'd leave it on.

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CaptainJack42 22 points 3 years ago

The short answer, as a ton of people already said in the comments of the video, is "hell no" it is not and it is most likely also not worth it. Back when the video came out I tested it (with unplugged network) on my system and the performance gain was ~1% which I'd consider well within the margin of error

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ryannathans 4 points 3 years ago

Mines about 60% faster, ymmv

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mara 2 points 3 years ago

What workload makes that much of a difference?

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ryannathans 1 point 3 years ago

Games on a 3rd gen i7

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mara 1 point 3 years ago

Which games?

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OsrsNeedsF2P 1 point 3 years ago

Aren't you the guy who runs one of the largest RuneScape private servers? Why tf are you disabling security measures

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ryannathans 1 point 3 years ago

Isolated machine for emulating old consoles

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dack 20 points 3 years ago

The system will be secure for personal use as before.

I wouldn't be so sure of that. CPU side channels allow data to be leaked across security contexts. For example, from a user process to sandboxed JavaScript in a browser, from kernel space to user space, or from one containerized process to another. This is a problem even on a single user system without any VMs.

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stardreamer 12 points 3 years ago

Many years ago when I was still doing my undergrad I had a cyber security prof talk about side channels:

”There's no way to prevent side-channels. As long as two components are sharing the same physical resource there will be side channels. The only problem is that these side channels are leaking way more bits than we expected.”

So the question here is how big does the side channel need to be to leak something sensitive from memory? Turning off mitigations will almost certainly lead to larger side channels. Whether that is worth the risk is up to you.

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GustavoM 10 points 3 years ago

...or you could opt for other ways to improve your PC performance. For instance, using equal values for both scaling_max_freq and scaling_min_freq gives you a quite considerable performance boost at the expense of (almost) nothing.

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wim 15 points 3 years ago

Well, you lose a lot of power efficiency, this would be massively detrimental to many peoples experiences if you do this on anything battery powered like a laptop.

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GustavoM 3 points 3 years ago

Eh...I see your point.

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wim 5 points 3 years ago

And does this still work with modern cpufreq schedulers like amd-pstate and the Intel equivalent? IIRC I couldn't simply set frequencies or select the userspace scheduler on 10th gen Intel and frequencies don't seem to be honoured by AMD pstate drivers on Zen4.

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Lemmy 8 points 3 years ago

It depends on how importent security is for that system and how devestating it would be if someone else got control over it and all accounts and devices connected to it.

Assuming there are sucessful exploits it would be like running everything as root and disabling all sandbox/isolation features from the kernel and browsers. I'd say you should not connect such a machine to the internet.

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StrangeAstronomer -3 points 3 years ago

Link for the video?

As a general rule of thumb, I've been told that anything less than a 50% performance boost is hardly noticeable.

I've also heard (but ready to stand corrected) that mitigation costs only about 10% CPU (depending on the CPU).

I don't get out of bed for a 10% performance boost.

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Presi300 -17 points 3 years ago

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