[Beowulf] Prevention of cpu frequency changes in cluster nodes (Was : cpupower, acpid & cpufreq)

Mikhail Kuzminsky mikky_m at mail.ru
Sun Jun 9 11:35:05 PDT 2013


 I installed OpenSuSE 12.3/x86-64 now. I may now say about the reasons why I am afraid of loading of cpufreq modules.

1) I found in /var/log/messages pairs of strings about governor like

[kernel] "cpuidle: using governor ladder"
[kernel] "cpuidle: using governor menu"

and strange for me
[kernel] ENERGY_PERF_BIAS: Set to 'normal', was 'performance'
[kernel] ENERGY_PERF_BIAS: View and update with x86_energy_perf_policy(8)

2) The presence on installed system of /sys/devices/system/cpu/cpufreq
                              /sys/devices/system/cpu/cpu0/cpuidle
     directories. cpuidle directories contains state0, state1 etc directories w/non-empty files.

3) But to prevent  cpu frequency changes I suppressed all like possibilities in BIOS.
4) And I don't have (as I wrote in my previous Beowulf message) 
/sys/devices/system/cpu/cpu0/cpufreq files.

Just the presence of this file is used by my /etc/init.d/cpufreq script as test of needs to load cpufreq kernel modules.

5) lsmod says that there is no cpufreq modules loaded.
Any comments ? Am I everywhere here right and should I ignore my afraids about kernel messages and presence of some /sys/devices/system/cpu/...... files ?

Mikhail Kuzminsky
Computer Assistance to Chemical Research Center RAS
Zelinsky Institute of Organic Chemistry
Moscow



 


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