Linux: AMD Phenom II and AMD Athlon II CPU Change Frequency On All Logical Cores

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I’ve AMD Athlon II processors based server and it does not change frequency on all logical cores under CentOS version 5.5 or RHEL Linux. How do I fix this problem?

The default CPU frequency scaling method uses powernow-k8 frequency driver module, and the ACPI data provided by BIOS, are not compatible with each other. It may not work at all to save power. To fix this problem Edit /etc/modprobe.conf file, enter:
# vi /etc/modprobe.conf
Append the following line:

options powernow-k8 preregister_acpi_perf=0

Save and close the file. It will work after reboot, however you can fix this for current setup by typing the following command as root user:
# /etc/init.d/ cpuspeed stop
# /sbin/rmmod powernow_k8
# /sbin/modprobe powernow-k8 preregister_acpi_perf=0
# /etc/init.d/cpuspeed start

Posted by: Vivek Gite

The author is the creator of nixCraft and a seasoned sysadmin, DevOps engineer, and a trainer for the Linux operating system/Unix shell scripting. Get the latest tutorials on SysAdmin, Linux/Unix and open source topics via RSS/XML feed or weekly email newsletter.