[CentOS-virt] No cpu throttling for Xeon E5405?

RedShift redshift at pandora.be
Sat May 23 07:16:28 UTC 2009


Dennis J. wrote:
> Hi,
> we bought some machines with 2 x quad core Xeon E5405 processors and 
> installed centos 5.3 on them. My problem is that I can't get the cpuspeed 
> service to work. No driver seems to claim responsibility for the throttling 
> and the fallback "modprobe acpi_cpufreq" in the cpuspeed init script just 
> yields a "No such device" message. According to the acpi information the 
> CPUs should support this just fine:
> 
> cat /proc/acpi/processor/CPU0/info:
> processor id:            0
> acpi id:                 0
> bus mastering control:   yes
> power management:        no
> throttling control:      yes
> limit interface:         yes
> 
> cat /proc/acpi/processor/CPU0/throttling:
> state count:             8
> active state:            T0
> states:
>     *T0:                  00%
>      T1:                  12%
>      T2:                  25%
>      T3:                  37%
>      T4:                  50%
>      T5:                  62%
>      T6:                  75%
>      T7:                  87%
> 
> At least half of the cores aren't really used at the moment under non-peak 
> load so we are wasting quite a bit of power with this. Any idea on how to 
> get this working?
> 
> Regards,
>    Dennis

FYI, throttling is not the same as frequency scaling. If your CPU is throttling it usually means it's overheating. 


Glenn


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