Intel Processor Performance Management on Debian Linux

To reduce power consumption and the level of magnetic radiation, Intel processors implement automatic frequency reduction, which can adversely affect server availability. Using the Debian Linux OS as an example, let's look at how to tune the processor for maximum performance.

First of all, using the apt-get install cpufrequutils command, you need to install a set of necessary utilities into the system. One of them, namely cpufreq-info, allows you to find out which frequency throttling policy is currently in use:

analyzing CPU 0:

driver: acpi-cpufreq

CPUs that run at the same hardware frequency: 0 1 2 3 4 5 6 7

CPUs which need to have their frequency coordinated by software: 0

maximum transition latency: 10.0us.

hardware limits: 800 MHz - 3.30 GHz

available frequency steps: 3.30 GHz, 3.30 GHz, 3.10 GHz, 2.90 GHz, 2.80 GHz, 2.60 GHz, 2.40 GHz, 2.20 GHz, 2.00 GHz, 1.90 GHz, 1.70 GHz, 1.50 GHz, 1.30 GHz, 1.20 GHz, 1000 MHz, 80 MHz

available cpufreq governors: userspace, power save, conservative, on-demand, performance

current policy: frequency should be between 800 MHz and 3.30 GHz.

The governor's "on-demand" may decide which speed to use

within this range.

the current CPU frequency is 800 MHz (asserted by call to hardware).

cpufreq stats: 3.30 GHz:0.04%, 3.30 GHz:0.00%, 3.10 GHz:0.00%, 2.90 GHz:0.00%, 2.80 GHz:0.00%, 2.60 GHz:0.00%, 2.40 GHz:0.00%, 2.20 GHz:0.00% , 2.00 GHz:0.00%, 1.90 GHz:0.00%, 1.70 GHz:0.00%, 1.50 GHz:0.00%, 1.30 GHz:0.00%, 1.20 GHz:0.00%, 1000 MHz:0.00%, 800 MHz:99.96% (5 )

As a rule, this is an on-demand policy, which means that the processor frequency automatically rises as the load increases. If your tasks are characterized by their short-term bursts, then the above algorithm may not have time to work properly. In such situations, it is recommended to change the policy to performance, which ensures that the processor will always run at maximum performance.

To do this, you need to edit or create the /etc/default/cpufrequutils file, adding the following option to it: GOVERNOR=performance. Use the update-rc.d -f on-demand remove command to disable the on-demand service. Reload the cpufrequutils service: service cpufrequutils reload. Finally, use cpufreq-info to make sure the changes have taken effect:

analyzing CPU 0: driver: acpi-cpufreq CPUs which run at the same hardware frequency: 0 1 2 3 4 5 6 7 CPUs which need to have their frequency coordinated by software: 0 maximum transition latency: 10.0us. hardware limits: 800 MHz - 3.30 GHz available frequency steps: 3.30 GHz, 3.30 GHz, 3.10 GHz, 2.90 GHz, 2.80 GHz, 2.60 GHz, 2.40 GHz, 2.20 GHz, 2.00 GHz, 1.90 GHz, 1.70 GHz, 1.50 GHz, 1.30 GHz, 1.20 GHz, 1000 MHz, 80 MHz available cpufreq governors: userspace, power save, conservative, on-demand, performance current policy: frequency should be between 800 MHz and 3.30 GHz.

The governor's "performance" may decide which speed to use

within this range.

the current CPU frequency is 3.30 GHz (asserted by call to hardware).

cpufreq stats: 3.30 GHz:1.19%, 3.30 GHz:0.00%, 3.10 GHz:0.00%, 2.90 GHz:0.00%, 2.80 GHz:0.00%, 2.60 GHz:0.00%, 2.40 GHz:0.00%, 2.20 GHz:0.00% , 2.00 GHz:0.00%, 1.90 GHz:0.00%, 1.70 GHz:0.00%, 1.50 GHz:0.00%, 1.30 GHz:0.00%, 1.20 GHz:0.00%, 1000 MHz:0.00%, 800 MHz:98.81% (8 )

In this case, we see that the performance policy is used, and the processor frequency is maximum. These settings will persist even after a server restart.

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