very high OS load, what cause?

Discussion in 'Fujitsu' started by Colourful Zone, Jun 22, 2009.

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  1. hydrocyanic

    hydrocyanic Pen Pal - Newbie

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    running RMclock shows that while CPU load is below 50%, OS load is always maintained at a high level, any reason for that to happen?

    it has been causing the machine to lag constantly

    this is running on windows 7 7100 build 32bit

    thanks

    i have 4gb ram physically and the only thing that consume ram is firefox at times it goes to 500-1gb. but it doesn't help all that much even after restarting the program or computer.

    would running a lot background applications be a cause?
     
  2. Frank

    Frank Scribbler - Standard Member Senior Member

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    just open the task manager and search for the process which stresses the CPU. Then you can kill this process, check if the issue is gone and try to solve the cause this process stressed the CPU all the time.
     
  3. hydrocyanic

    hydrocyanic Pen Pal - Newbie

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    it isn't the CPU load that is high, instead, the OS load, i don't know what that is, my memory usage is only 40-50% and CPU load is lower than that also

    what is OS load anyways?
     
  4. Frank

    Frank Scribbler - Standard Member Senior Member

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    This are my experiences:
    OS load is the OS load, just as you see in the task manager. If it's high then you have a background process running, which stresses the OS and thus the CPU. The OS load should be below 5% or even 0% when idle.

    The CPU load is strange and I've never understood it. My experience is that the higher the CPU load is the less power the CPU consumes. When idle the CPU load is around 70%. When I turn on BT and connect a device, then it drops to 0%, but the power consumption increases.
     
  5. hydrocyanic

    hydrocyanic Pen Pal - Newbie

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    thx, i guess i have too many background apps, i was suspecting that but couldn't be sure
     
  6. Colourful Zone

    Colourful Zone Using T2020 thru DIY e-PCIe I/F, now using T904

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    Hi Frank,

    As my knowledge and understanding, the CPU load is the usage of the CPU but it is not the meter to show you how heavy the workload of the CPU. You can understand it as the inverse of the idle time of CPU.

    For example, Susan is very busy to talk on the phone. She has no time to do the other work but in fact she is talking something not important or just in joking so their workload is very light or even nil. However, Peter is the worker and he has to move heavy goods once every 3 minutes. His workload is actually very heavy(hot) but he has idle time bewteen moving the heavy goods.

    Thus, why the CPU load is high without turning on BT device but there is no CPU load after you turned on the BT device, it is becuase without turning on the BT device, the hardware(mainly in chipsets & CPU) will be in the sleep mode(enable the Popup/Popdown mode in chipsets register) but the chipsets & CPU have to monitor(it is actually a busy task but very light workload) the other hardware triggers(move the mouse/type in the keyboard, etc..) & software requests(read/write data to harddisk or memory, etc..) to turn on the chipsets & CPU back to normal mode if needed(otherwise, without monitoring, the system will be in sleep mode forever and it cannot back to normal fully on mode). Thus, you can see the CPU load is high but the power consumption is less than CPU load is zero.

    After you turn on the BT device, the CPU load is zero since it do not need to monitor the trigger & request event. The activity of BT device will be processed by the BT module and chipsets. It do not need CPU to work with them so the CPU load is zero. However, since the chipsets is in fully on mode as well as the BT module is on, the power consumption is higher than the BT device is off.

    I hope the above explanation can help you to understand the meaning of CPU load and the strange thing about the power consumption when BT turn off/on. :)

     
  7. Frank

    Frank Scribbler - Standard Member Senior Member

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    Thank you for the explanation, sadly I still don't get it.
    I don't have a BT device connected, only my PC. CPU load is high. Then I connect the BT module, connect a device and the CPU load drops to 0%.
    But the CPU still has to do the other activities it did before, too. So it has to monitor the trigger and request events of all the remaining hardware. So the CPU load should increase, because now it also has to monitor the BT hardware.

    If the CPU load is at about 70% and I move the pen above the display, then the CPU load increases. That's logical. But it does not make sense if I turn on the BT device, thus add an additional device, and the CPU load decreases.
     
  8. Colourful Zone

    Colourful Zone Using T2020 thru DIY e-PCIe I/F, now using T904

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    Maybe it can be understood that when the chipsets go to sleep mode by enabling the Popup/Popdown mode in chipsets register, most of trigger work will be done by CPU so CPU load will be higher.

    Tuning on the BT device is just an example to force chipsets cannot go to sleep mode since the activity between BT module and chipsets is quite busy, so you can see that situation. You can get the similar effect by running "chkdsk" command in MS-DOS Command Prompt, the CPU load is nearly zero also even there is no BT device is ON.

    I think the data of the CPU load is come from the CPU registers by calling the corresponding CPU instructions. Detail you can go to here, http://www.intel.com/Assets/PDF/manual/253669.pdf, Intel® 64 and IA-32 Architectures Software Developer's Manual, Volume 3B: System Programming Guide, to study about it, I think it is about the Performace Monitor/Counter. :)
     
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