Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756062Ab1CXMGO (ORCPT ); Thu, 24 Mar 2011 08:06:14 -0400 Received: from rcsinet10.oracle.com ([148.87.113.121]:17184 "EHLO rcsinet10.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753907Ab1CXMGM (ORCPT >); Thu, 24 Mar 2011 08:06:12 -0400 Date: Thu, 24 Mar 2011 08:05:22 -0400 From: Konrad Rzeszutek Wilk To: Len Brown Cc: Trinabh Gupta , arjan@linux.intel.com, peterz@infradead.org, suresh.b.siddha@intel.com, benh@kernel.crashing.org, venki@google.com, ak@linux.intel.com, linux-kernel@vger.kernel.org, sfr@canb.auug.org.au, xen-devel@lists.xensource.com Subject: Re: [RFC PATCH V4 4/5] cpuidle: driver for xen Message-ID: <20110324120522.GB29294@dumpdata.com> References: <20110322123208.28725.30945.stgit@tringupt.in.ibm.com> <20110322123324.28725.3131.stgit@tringupt.in.ibm.com> <20110322145054.GB26952@dumpdata.com> <4D89C40B.4020809@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.20 (2009-06-14) X-Source-IP: acsmt356.oracle.com [141.146.40.156] X-Auth-Type: Internal IP X-CT-RefId: str=0001.0A090207.4D8B3384.0105,ss=1,fgs=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1290 Lines: 38 On Thu, Mar 24, 2011 at 03:18:14AM -0400, Len Brown wrote: > Is a CONFIG_XEN kernel supposed to use just HLT in idle? For right now.. > > xen_arch_setup() does this: > > pm_idle = default_idle; > boot_option_idle_override = IDLE_HALT; > > which has that effect. I guess this makes sense b/c the > CONFIG_XEN kernel is Dom0 and the real C-sates are done > by the hypervisor? Correct. There are some patches that make the C-states be visible in the Linux kernel, but that hasn't been ported over yet. > > Would the same CONFIG_XEN kernel binary ever not > run xen_arch_setup(), run on raw hardware, and want ever not? I am not sure of the question, so let me state: The Linux kernel if compiled with CONFIG_XEN, and if run on native hardware, would _never_ run 'xen_arch_setup()'*. It would run the normal, native type setup. > to use idle states other than HLT? > *: It could if you really really wanted. You would need to change the GRUB2 to inject some extra data in the 'sub_hardware' flag to be the Xen specific. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/