On Sun, 2009-06-21 at 17:20 +0800, Mahmood Naderan wrote: > I got more confused... In my first post if you see, BIOS reports C1, > C2 and C6. Even it does not support C3 (!), but here is the output of > "cat /proc/acpi/processor/CPU0/power": > > active state: C0 > max_cstate: C8 > bus master activity: 00000000 > maximum allowed latency: 2000000000 usec > states: > C1: type[C1] promotion[--] demotion[--] > latency[001] usage[00000063] duration[00000000000000000000] > C2: type[C2] promotion[--] demotion[--] > latency[001] usage[00017466] duration[00000000000014422985] > C3: type[C3] promotion[--] demotion[--] > latency[162] usage[00096196] duration[00000000000650582389] > > So I think something (BIOS or CPU or OS) is malfunctioning and does > not report correctly. > Now the big question is, will my system (a combination of CPU, BIOS > and OS) enter C3 (or even deeper states)? What is your problem? The following info only tells us that the following CPU C-state is supported on the CPU. >Your CPU supports the following C-states : C1 C2 C3 C4 C5 C6 But not all the CPU C-state is not used by the OS. It seems that the C1/C2/C6 is used on this box. At the same time it is noted that the cpu C-state is different with the ACPI C-state. In fact BIOS will do the mapping between the CPU C-state and ACPI C-state. And ACPI C-state is used by the OS. For example: on your box: The CPU C6 is mapped to ACPI C3-state. >From the info of "cat /proc/acpi/processor/CPU*/power" we know that your box can enter the ACPI C3, which is mapped to the CPU C6. Of course it is the deep C-state. Thanks. > > -------------------------- > *Mahmood Naderan* > > > > > On Sun, Jun 21, 2009 at 2:34 AM, Ananth Narayan > S<ananth.narayan@xxxxxxxxx> wrote: > > You could see it that way. The OS will use the C states exported by > > the BIOS. If C4/C5 are not exported, the OS will not even know that > > such states exist. If you query /proc/acpi/CPU*/power, you'll probably > > see just three C states listed (C1, C2, C3). Typically the last > > C-state (C3) in that will map to the lowest C-state supported by the > > processor. > > > > -- Ananth > > > > > > > > > > On Sat, Jun 20, 2009 at 8:46 AM, Mahmood Naderan<mahmood.nt@xxxxxxxxx> wrote: > >> Hi, > >> So if my understanding is correct, the BIOS does not allow the CPU to > >> enter C4 and C5 states. Right? > >> > >> -------------------------- > >> *Mahmood Naderan* > >> > >> > >> > >> > >> On Sat, Jun 20, 2009 at 7:56 PM, Ananth Narayan > >> S<ananth.narayan@xxxxxxxxx> wrote: > >>> Intel processors export a max supported c state value. But when it > >>> comes to c states, typically the one that provides max power savings > >>> is exported by the BIOS. The intermediate ones aren't. > >>> > >>> -- Ananth Narayan S. > >>> > >>> > >>> > >>> > >>> On Fri, Jun 19, 2009 at 10:07 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* > >>>> -- > >>>> To unsubscribe from this list: send the line "unsubscribe linux-acpi" in > >>>> the body of a message to majordomo@xxxxxxxxxxxxxxx > >>>> More majordomo info at http://vger.kernel.org/majordomo-info.html > >>>> > >>> > >> > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-acpi" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
