Linux: How to disable mitigations for CPU vulnerabilities
Re: Linux: How to disable mitigations for CPU vulnerabilities
While I never profiled its effects, I have mitigations off on all of my DC-dedicated computers.
It was a small nuisance to figure out how to set the GRUB config accordingly in Mint.
In OpenSuse, there is a dialogue for this in their central system management GUI.
It was a small nuisance to figure out how to set the GRUB config accordingly in Mint.
In OpenSuse, there is a dialogue for this in their central system management GUI.
- biodoc
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Re: Linux: How to disable mitigations for CPU vulnerabilities
For others using Mint:
sudo nano /etc/default/grub
Before editing:
GRUB_DEFAULT=0
GRUB_TIMEOUT_STYLE=hidden
GRUB_TIMEOUT=0
GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian`
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
GRUB_CMDLINE_LINUX=""
After editing:
GRUB_DEFAULT=0
GRUB_TIMEOUT_STYLE=hidden
GRUB_TIMEOUT=0
GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian`
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash mitigations=off"
GRUB_CMDLINE_LINUX=""
Save the change.
sudo update-grub
reboot
Re: Linux: How to disable mitigations for CPU vulnerabilities
I did not rtfm but I skimmed it, and didn't find how to put more than one command in that line. Some of my PCs have this:
GRUB_CMDLINE_LINUX_DEFAULT="quiet vsyscall=emulate"
I'm not sure how to add that in, it looks like just put "mitigations=off" into the quotation marks...?
For instance:
GRUB_CMDLINE_LINUX_DEFAULT="quiet vsyscall=emulate mitigations=off"
GRUB_CMDLINE_LINUX_DEFAULT="quiet vsyscall=emulate"
I'm not sure how to add that in, it looks like just put "mitigations=off" into the quotation marks...?
For instance:
GRUB_CMDLINE_LINUX_DEFAULT="quiet vsyscall=emulate mitigations=off"
Re: Linux: How to disable mitigations for CPU vulnerabilities
Correct. You can enter as many kernel parameters as you need, separated by space characters, and in any order.
Added in 4 minutes 32 seconds:
Perhaps GPGPU workloads profit more, as they involve more calls into the kernel, and device I/O.
Added in 4 minutes 32 seconds:
Every percent counts. ;-)
Perhaps GPGPU workloads profit more, as they involve more calls into the kernel, and device I/O.
Re: Linux: How to disable mitigations for CPU vulnerabilities
Thanks for being patient with such elementary queries, Stefan. I don't think I can understate how valuable your advice has been over the years.
Last edited by crashtech on Wed Jan 13, 2021 3:10 pm, edited 1 time in total.
- biodoc
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Re: Linux: How to disable mitigations for CPU vulnerabilities
I shut down the 2P Ivy beast for now. The PPD is between a 3700X and a 3900X and it draws 310 watts from the wall with turbo boost off. I'll replace it when you can actually buy hardware sometime in the future.
Re: Linux: How to disable mitigations for CPU vulnerabilities
Re: Linux: How to disable mitigations for CPU vulnerabilities
We need nitrous for PCs!
Re: Linux: How to disable mitigations for CPU vulnerabilities
Remember the turbo button from the 90s?