Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751153Ab1DAEJj (ORCPT ); Fri, 1 Apr 2011 00:09:39 -0400 Received: from vms173017pub.verizon.net ([206.46.173.17]:53486 "EHLO vms173017pub.verizon.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750763Ab1DAEJi (ORCPT ); Fri, 1 Apr 2011 00:09:38 -0400 Date: Fri, 01 Apr 2011 00:09:25 -0400 (EDT) From: Len Brown X-X-Sender: lenb@x980 To: Peter Zijlstra Cc: Vaidyanathan Srinivasan , Trinabh Gupta , arjan@linux.intel.com, Stephen Rothwell , suresh.b.siddha@intel.com, benh@kernel.crashing.org, venki@google.com, ak@linux.intel.com, linux-kernel@vger.kernel.org, xen-devel@lists.xensource.com Subject: Re: cpuidle asymmetry (was Re: [RFC PATCH V4 5/5] cpuidle: cpuidle driver for apm) In-reply-to: <1301577536.4859.249.camel@twins> Message-id: References: <20110322123208.28725.30945.stgit@tringupt.in.ibm.com> <20110322123336.28725.29810.stgit@tringupt.in.ibm.com> <20110323121458.ec7cdaf9.sfr@canb.auug.org.au> <4D89CA7D.8080108@linux.vnet.ibm.com> <4D8B550D.5000409@linux.vnet.ibm.com> <20110325180156.GC19214@dirshya.in.ibm.com> <1301577536.4859.249.camel@twins> User-Agent: Alpine 2.02 (LFD 1266 2009-07-14) MIME-version: 1.0 Content-type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 898 Lines: 25 > > Moorestown is already an example of an asymmetric system, > > since its deepest c-state is available on cpu0, but not on cpu1. > > So it needs different tables for each cpu. > > wtf are these hardware guys smoking and how the heck are we supposed to > schedule on such a machine? Prefer to keep cpu1 busy while idling cpu0? they are smoking micro-amps:-) S0i3 on cpu0 can be entered only after cpu1 is already off-line, among other system hardware dependencies... So it makes no sense to export S0i3 as a c-state on cpu1. When cpu1 is online, the scheduler treats it as a normal SMP. cheers, -Len Brown, Intel Open Source Technology Center -- 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/