power management on atom cpus

    Hi - Is there a power management feature included in OMV for Atom D500 series CPUs? Although these cpus are low watts already I think it is worth using the powersave governor using the Intel Pentium 4 clock modulation as the default ACPI Processor P-States driver does not work. What would be nice to have as a "plugin" is the cpu governor automatically switches to powersave after being idle for eg 15 minutes ( no network activity, no disk, etc ) and whenever OMV is accessed the governor switches back automatically to the "performance" governor.

    Yes, there is a feature already for any Intel processor (and I assume works for AMD as well) with speedstep functions. Go to power management, and enable "Monitoring". In reality, the CPU is the one that decides the power state with the Speedstep tech from Intel, depending on load. So, if you are simply going through the GUI, it may not merit full CPU power and Speedstep will keep the CPU running at probably around 600MHz. Once there's more load, then the clock speed will increase accordingly all the way to 1600MHz with an Atom D500. Power stepping is almost instant with little to no noticeable performance hit.

    cheers for your response - That feature is known but as you also mention this is for cpus that support the intel speedstep and that is exactly the atom d500 cpus do not support (just open the link I included in my inital post). There is a clear "NO" next to Enhanced Intel SpeedStep® Technology, hence my inital question to request a power feature (plugin) also for these atom cpus. imho some performance tweaks can be added utilising the the Intel Pentium 4 clock modulation in the kernel as the ACPI Processor P-States driver does not work ( which is for speedstep ) on these cpus.

    I could have sworn that these CPUs have SpeedStep, I just learned something. Well, I do remember using this system with FreeNAS in the past, and it was able to reduce the speed on-demand, so I assumed that this was SpeedStep in action. Sorry, I don't think I have an answser for you.

    Think a nice reference would be also this page.


    It seems this cpu series really doesn't have freq scaling, so basically forget about any governors and such as it is N/A to this processor and just load the p4_clockmod module, hopefully a way can be found to swich between powersave and performance (userspace?).

    I think I am getting closer using powernowd :
    find below the output ( watch the cpufreq stats :(


    Report errors and bugs to cpufreq@vger.kernel.org, please.
    analyzing CPU 0:
    driver: p4-clockmod
    CPUs which run at the same hardware frequency: 0 2
    CPUs which need to have their frequency coordinated by software: 0 2
    maximum transition latency: 10.00 ms.
    hardware limits: 225 MHz - 1.80 GHz
    available frequency steps: 225 MHz, 450 MHz, 675 MHz, 900 MHz, 1.13 GHz, 1.35 GHz, 1.58 GHz, 1.80 GHz
    available cpufreq governors: userspace, powersave, performance
    current policy: frequency should be within 225 MHz and 1.80 GHz.
    The governor "userspace" may decide which speed to use
    within this range.
    current CPU frequency is 1.80 GHz (asserted by call to hardware).
    cpufreq stats: 225 MHz:78.17%, 450 MHz:0.70%, 675 MHz:0.70%, 900 MHz:0.95%, 1.13 GHz:0.94%, 1.35 GHz:0.83%, 1.58 GHz:4.23%, 1.80 GHz:13.48% (169)
    analyzing CPU 1:
    driver: p4-clockmod
    CPUs which run at the same hardware frequency: 1 3
    CPUs which need to have their frequency coordinated by software: 1 3
    maximum transition latency: 10.00 ms.
    hardware limits: 225 MHz - 1.80 GHz
    available frequency steps: 225 MHz, 450 MHz, 675 MHz, 900 MHz, 1.13 GHz, 1.35 GHz, 1.58 GHz, 1.80 GHz
    available cpufreq governors: userspace, powersave, performance
    current policy: frequency should be within 225 MHz and 1.80 GHz.
    The governor "userspace" may decide which speed to use
    within this range.
    current CPU frequency is 1.80 GHz (asserted by call to hardware).
    cpufreq stats: 225 MHz:0.00%, 450 MHz:0.00%, 675 MHz:0.00%, 900 MHz:0.00%, 1.13 GHz:0.00%, 1.35 GHz:0.00%, 1.58 GHz:0.00%, 1.80 GHz:100.00%
    analyzing CPU 2:
    driver: p4-clockmod
    CPUs which run at the same hardware frequency: 0 2
    CPUs which need to have their frequency coordinated by software: 0 2
    maximum transition latency: 10.00 ms.
    hardware limits: 225 MHz - 1.80 GHz
    available frequency steps: 225 MHz, 450 MHz, 675 MHz, 900 MHz, 1.13 GHz, 1.35 GHz, 1.58 GHz, 1.80 GHz
    available cpufreq governors: userspace, powersave, performance
    current policy: frequency should be within 225 MHz and 1.80 GHz.
    The governor "userspace" may decide which speed to use
    within this range.
    current CPU frequency is 1.80 GHz (asserted by call to hardware).
    cpufreq stats: 225 MHz:78.17%, 450 MHz:0.70%, 675 MHz:0.70%, 900 MHz:0.95%, 1.13 GHz:0.94%, 1.35 GHz:0.83%, 1.58 GHz:4.23%, 1.80 GHz:13.48% (169)
    analyzing CPU 3:
    driver: p4-clockmod
    CPUs which run at the same hardware frequency: 1 3
    CPUs which need to have their frequency coordinated by software: 1 3
    maximum transition latency: 10.00 ms.
    hardware limits: 225 MHz - 1.80 GHz
    available frequency steps: 225 MHz, 450 MHz, 675 MHz, 900 MHz, 1.13 GHz, 1.35 GHz, 1.58 GHz, 1.80 GHz
    available cpufreq governors: userspace, powersave, performance
    current policy: frequency should be within 225 MHz and 1.80 GHz.
    The governor "userspace" may decide which speed to use
    within this range.
    current CPU frequency is 1.80 GHz (asserted by call to hardware).
    cpufreq stats: 225 MHz:0.00%, 450 MHz:0.00%, 675 MHz:0.00%, 900 MHz:0.00%, 1.13 GHz:0.00%, 1.35 GHz:0.00%, 1.58 GHz:0.00%, 1.80 GHz:100.00%

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