Hi,
1- where can I find powertop source code?
2- what is the name of intel utility in windows as you said?
--------------------------
*Mahmood Naderan*
On Sun, Jun 21, 2009 at 2:19 PM, Edward Shao<laface.tw@xxxxxxxxx> wrote:
> Hi~
> It's all depended on how utility to interpret raw information (both
> information reported by CPU or BIOS).
> You can check source code of powertop for detail information.
> For BIOS part, powertop checks value of mwait hint register reported
> by ACPI _CST method.
>
> As my experience, powertop will cause a misleading sometimes,
> especially for new Intel CPU.
> For example:
> BIOS engineer said they followed Intel BIOS porting guide to report an
> accuracy C-state (C6) information via ACPI _CST method.
> However powertop said BIOS only reports C3. (but Intel utility under
> Windows said CPU can enter C6).
>
> Best Regards,
> Edward
>
> On Sat, Jun 20, 2009 at 2:54 PM, Mahmood Naderan<mahmood.nt@xxxxxxxxx> wrote:
>> Hi,
>>> Only simple check value of edx.
>>> Well, unless CPU uses CPUID.5.EDX[31:20], the reserved area.
>>
>> You mean that powertop is not correctly reading the states? Do you
>> mean that the BIOS reports better that the CPU ?
>>
>> --------------------------
>> *Mahmood Naderan*
>>
>>
>>
>> On Sat, Jun 20, 2009 at 7:26 AM, Edward Shao <laface.tw@xxxxxxxxx> wrote:
>>>
>>> Hi Mahmood,
>>>
>>> So far as I know, if your CPU is Intel, powertop maybe cause a misleading.
>>> Powertop uses CPUID.5.EDX to check CPU supported C states.
>>> According Intel's spec (Intel Processor Identification and the CPUID
>>> Instruction (Application Note 485), a CPU only has
>>>
>>> C0, C1, C2, C3, C4 (prior Core i7)
>>> C0, C1, C2, C6, C7 (Core i7 and subsequent)
>>>
>>> Check with source code of powertop
>>> while (edx) {
>>> if (edx&7)
>>> printf("C%i ", i);
>>> edx = edx >> 4;
>>> i++;
>>> }
>>> Only simple check value of edx.
>>> Well, unless CPU uses CPUID.5.EDX[31:20], the reserved area.
>>>
>>> Ps: I does not check AMD's spec.
>>>
>>> Best Regards,
>>> Edward
>>>
>>>
>>> On Sat, Jun 20, 2009 at 1:07 AM, Mahmood Naderan<mahmood.nt@xxxxxxxxx> wrote:
>>> > Hi,
>>> > I have run powertop with root permission with both AC and batter powers. The
>>> > reported C_States are the same and strange:
>>> >
>>> > mahmood@magma:~$ sudo powertop
>>> > PowerTOP 1.11 (C) 2007, 2008 Intel Corporation
>>> >
>>> > Collecting data for 5 seconds
>>> >
>>> > Your CPU supports the following C-states : C1 C2 C3 C4 C5 C6
>>> > Your BIOS reports the following C-states : C1 C2 C6
>>> >
>>> > Where are C4 and C5?
>>> >
>>> > --------------------------
>>> > *Mahmood Naderan*
>>> > --
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>>> >
>>>
>>>
>>>
>>> --
>>> Best Regards,
>>> Edward
>> --
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>
>
>
> --
> Best Regards,
> Edward
>
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