From mboxrd@z Thu Jan 1 00:00:00 1970 From: Edward Shao Subject: Re: BIOS and CPU C_states are strange Date: Sun, 21 Jun 2009 18:06:11 +0800 Message-ID: References: <1acba2fa0906191006i3cd5a035pf18e096fdb92e27e@mail.gmail.com> <1acba2fa0906191007l4b8d5c17id068d868e6178fb8@mail.gmail.com> <1acba2fa0906200846r751cf235q9e155e5445090d40@mail.gmail.com> <1acba2fa0906210218o59a6c92fi86e30891c0816b5d@mail.gmail.com> <1acba2fa0906210220p27b9e902xd640029fa0122b24@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from mail-px0-f202.google.com ([209.85.216.202]:53432 "EHLO mail-px0-f202.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752890AbZFUKGJ convert rfc822-to-8bit (ORCPT ); Sun, 21 Jun 2009 06:06:09 -0400 Received: by pxi40 with SMTP id 40so826727pxi.33 for ; Sun, 21 Jun 2009 03:06:11 -0700 (PDT) In-Reply-To: <1acba2fa0906210220p27b9e902xd640029fa0122b24@mail.gmail.com> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: linux-acpi@vger.kernel.org Hi~ In your case, typically C3 should map to CPU C6. Best Regards, Edward On Sun, Jun 21, 2009 at 5:20 PM, 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 (!), =A0but here is the output= of > "cat /proc/acpi/processor/CPU0/power": > > active state: =A0 =A0 =A0 =A0 =A0 =A0C0 > max_cstate: =A0 =A0 =A0 =A0 =A0 =A0 =A0C8 > bus master activity: =A0 =A0 00000000 > maximum allowed latency: 2000000000 usec > states: > =A0 =A0C1: =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0type[C1] promotion[--] = demotion[--] > latency[001] usage[00000063] duration[00000000000000000000] > =A0 =A0C2: =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0type[C2] promotion[--] = demotion[--] > latency[001] usage[00017466] duration[00000000000014422985] > =A0 =A0C3: =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0type[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)? > > -------------------------- > *Mahmood Naderan* > > > > > On Sun, Jun 21, 2009 at 2:34 AM, Ananth Narayan > S 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 probab= ly >> 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 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 wrote: >>>> Intel processors export a max supported c state value. But when it >>>> comes to c states, typically the one that provides max power savin= gs >>>> is exported by the BIOS. The intermediate ones aren't. >>>> >>>> -- Ananth Narayan S. >>>> >>>> >>>> >>>> >>>> On Fri, Jun 19, 2009 at 10:07 AM, Mahmood Naderan 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 =A0 (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-a= cpi" in >>>>> the body of a message to majordomo@vger.kernel.org >>>>> More majordomo info at =A0http://vger.kernel.org/majordomo-info.h= tml >>>>> >>>> >>> >> > -- > To unsubscribe from this list: send the line "unsubscribe linux-acpi"= in > the body of a message to majordomo@vger.kernel.org > More majordomo info at =A0http://vger.kernel.org/majordomo-info.html > --=20 Best Regards, Edward -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html