From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Mathew Brown" Subject: Re: SMP C-states on x86_64 Status Date: Tue, 07 Nov 2006 04:51:51 -0800 Message-ID: <1162903911.32119.275205906@webmail.messagingengine.com> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Return-path: Received: from out1.smtp.messagingengine.com ([66.111.4.25]:64489 "EHLO out1.smtp.messagingengine.com") by vger.kernel.org with ESMTP id S1753528AbWKGMvv (ORCPT ); Tue, 7 Nov 2006 07:51:51 -0500 Content-Disposition: inline Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Len Brown Cc: linux-acpi@vger.kernel.org Thanks a lot for your input Len. For my 16 core machine, cat /proc/acpi/processor/*/power gives the following: active state: C1 default state: C1 bus master activity: 00000000 states: *C1: promotion[--] demotion[--] latency[000] usage[0000000000] C2: C3: So I gather that this means that even with CPU frequency scaling, I'm really not doing anything since the voltage and power going to the CPU are going to be constant until I upgrade to 2.6.18. Am I correct? Len Brown wrote: > On Sunday 05 November 2006 06:37, Mathew Brown wrote: >> Hi, >> I just saw Adrian's post on a patch to add SMP C-states on x86_64 to >> kernel 2.6.16. Is there anywhere I can find the current status of >> C-states on SMP machines? I have a 16-core machine running RHEL with >> kernel 2.6.9-34 and it shows only C0, nothing else. I checked the >> DSDT and it compiled without error. Any ideas? Thanks for your help. > > This support (bugzilla 5653) shipped starting in 2.6.18, and I sent it to Adrian > for 2.6.16.stable -- and it appears it will pop out in 2.6.16.31. > > Re: your 16 core machine running 2.6.9... > What does /proc/acpi/processor/*/power say? > I would expect it to say C1 only. > > I would not expect this box to grow deeper C-states upon the support above. > The only SMP boxes with C-states deeper than C1 that I'm aware of today > are laptops. > > cheers, > -Len > > > -- Mathew Brown mathewbrown@fastmail.fm -- http://www.fastmail.fm - The way an email service should be