APM/ACPI reduce heat produced.



  • I have a Neoware CA2 with 1GB of RAM and VIA 800Mhz processor and a quad ethernet 10/100 installed on this giving me a total of 5 ethernet ports.
    On this I have a full install of 2.0.3-RELEASE (i386) built on Fri Apr 12 10:22:57 EDT 2013.
    This install is on a USB 8GB with USB stabilization delay added to make boot unattended.
    ACPI is NOT turned off.

    There are three broadband connected to modems with three different carriers and they are on load balance using same tier gateway.

    This is because where I live in India now, the internet connection is like a Yo yo and I need a reliable net access.

    This works flawlessly (For those who need recipe, I will gladly send).

    **What I observe is that this gets plenty hot even when in a well ventilated area and not in use and is idle with no one using the net….... Like when I come back from work.

    Can any one of you guru folks, tell me how to tune it so that it is throttling the processor down and goes into low power consumption mode?**

    Much appreciate.

    Anil Garg


  • Netgate Administrator

    Have you tried enabling powerd in System: Advanced: Miscellaneous: ?
    That is the usual way to enable power saving cpu features. I'm not sure how well it works for VIA cpus though.

    Steve



  • @stephenw10:

    Have you tried enabling powerd in System: Advanced: Miscellaneous: ?
    That is the usual way to enable power saving cpu features. I'm not sure how well it works for VIA cpus though.

    Steve

    It's been my experience that powerd is pretty much useless if you're already using a low-power CPU.  The bulk of my pfSense boxes are Atoms or mobile C2Ds and none see more than a few hundred mW drop when enabling powerd.


  • Netgate Administrator

    That has been my experience with newer CPUs also. However it depends how you are testing.
    Powerd supports several actual power saving schemes but the most relevant is est(4), which supports Intel enhanced speedstep. The other schemes do little to actually reduce power use. If you look at the est source the only CPUs it supports directly are the Pentium-M and some VIA CPUs, which is why I suggested it. Looking at it now though it looks like the C3 in the Neoware isn't supported. Support for any other CPUs relies on getting the voltage/frequency information from the BIOS via ACPI. Many bioses are buggy or flat out don't give anything to FreeBSD so you may have that problem. Even if you have have a bios that plays nice and a CPU that supports EIST you may find almost no decrease in power consumption if it also supports low sleep states. If you are testing at idle the CPU may be spending almost all it's time in C2 or C3 which is significantly lower consumption than any P state offered by EIST. The only time you will see any saving are at partial loads, when the CPU cannot drop to a low C state, which is more difficult to test.

    I'd be interested in anyones thoughts on this. I spent a while trying to get this working on one of my boxes but had to give up.

    Steve



  • Thanks Steve, Jason. I have PowerD enabled.
    I checked web and inquired CPU and got following response:

    
    dmesg | grep CPU
    CPU: VIA Nehemiah (800.32-MHz 686-class CPU)
    cpu0: <acpi cpu="">on acpi0
    acpi_throttle0: <acpi cpu="" throttling="">on cpu0</acpi></acpi> 
    

    Appreciate any further advice.

    Anil Garg



  • @garg_art2002:

    Thanks Steve, Jason. I have PowerD enabled.
    I checked web and inquired CPU and got following response:

    
    dmesg | grep CPU
    CPU: VIA Nehemiah (800.32-MHz 686-class CPU)
    cpu0: <acpi cpu="">on acpi0
    acpi_throttle0: <acpi cpu="" throttling="">on cpu0</acpi></acpi> 
    

    Appreciate any further advice.

    Anil Garg

    Do you have polling enabled?  If so, your CPU will run at 100% all the time.

    Beyond that, you really haven't given any actual numbers for power consumption.  It could just be that the case your system is in has poor airflow (or none at all) and is retaining all the heat.  I've got a couple <10W fanless boxes that run a CPU temp of 55-60C and an external case temp of around 35C with no ill effects.



  • Thanks Jason. I do not have the Polling on. Also let me grab a power meter for us to know beyond "I know my box is hot even if unused".
    Best regards.

    Anil

    @Jason:

    @garg_art2002:

    Thanks Steve, Jason. I have PowerD enabled.
    I checked web and inquired CPU and got following response:

    
    dmesg | grep CPU
    CPU: VIA Nehemiah (800.32-MHz 686-class CPU)
    cpu0: <acpi cpu="">on acpi0
    acpi_throttle0: <acpi cpu="" throttling="">on cpu0</acpi></acpi> 
    

    Appreciate any further advice.

    Anil Garg

    Do you have polling enabled?  If so, your CPU will run at 100% all the time.

    Beyond that, you really haven't given any actual numbers for power consumption.  It could just be that the case your system is in has poor airflow (or none at all) and is retaining all the heat.  I've got a couple <10W fanless boxes that run a CPU temp of 55-60C and an external case temp of around 35C with no ill effects.


  • Netgate Administrator

    That CPU supports power saving in the form of Via's Long Haul. However there doesn't appear to be a FreeBSD driver for it.  :(

    Steve


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