Disabling AMD's equivalent (on a Zen-1 Epyc) of Intel's "turbo boost" at runtime?

Question

This may be a terminology problem at my end and a duplicate: On Intel CPUs, I can relatively easy disable turbo boost at runtime by running something like

echo 1 > /sys/devices/system/cpu/intel_pstate/no_turbo

The CPU then runs at its base clock without "turboing up". The nice thing is that I do not need to change BIOS/(U)EFI settings for that.

What would be the equivalent (in terms of both terminology and commands) on AMD CPUs, specifically on a Zen-1 Epyc?

I am trying to run the CPU at constant (low) speed for consistent benchmark results. I am trying to compare different software implementations of algorithms.

score 11 · Accepted Answer · answered Nov 22 '20 at 16:09

11

By default, AMD processors use the acpi-cpufreq CPU frequency scaling driver.
Check via:

grep . /sys/devices/system/cpu/cpufreq/policy*/scaling_driver

For that driver, to disable turbo boost, do:

echo "0" | sudo tee /sys/devices/system/cpu/cpufreq/boost

answered Nov 22 '20 at 16:09

Doug Smythies

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And how to disable it again? – ThomasRS Jan 15 '21 at 22:58
Is a reboot necessary? – ThomasRS Jan 15 '21 at 23:05
2

@ThomasRS : No, the setting will be lost through a re-boot. echo 1 | sudo tee /sys/devices/system/cpu/cpufreq/boost to reverse the setting. – Doug Smythies Jan 16 '21 at 03:42
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the double quotes around the zero are not needed – cipper Nov 29 '22 at 10:56
I am using EPYC 7543 on Ubuntu 22, and it does not have this file, and msr-tools do not work as well. Can someone help me? – 1a1a11a Jul 27 '23 at 21:46
1

@1a1a11a : Things have changed that answer was written. You might find that the newer amd-pstate CPU frequency driver is now the default. I don't know that there is an equivalent boost (turbo-core) disable for that driver (not sure). – Doug Smythies Jul 27 '23 at 22:37

score 0 · Answer 2 · answered Jun 11 '22 at 14:36

To make a persistent change, this command needs to be run by sudo on reboot. One way to do this is to append the setting to the crontab config file:

Edit crontab setting as admin:

sudo crontab -e

and append the command at the end of the config file:

@reboot echo "0" | tee /sys/devices/system/cpu/cpufreq/boost

Moreover, if you are using gnome, you can check this awesome extension Frequency Boost Switch to toggle the setting using GUI.

Disabling AMD's equivalent (on a Zen-1 Epyc) of Intel's "turbo boost" at runtime?

2 Answers2

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