From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:55599) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VMkbq-0006WN-2b for qemu-devel@nongnu.org; Thu, 19 Sep 2013 16:14:02 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VMkbh-0001QA-4X for qemu-devel@nongnu.org; Thu, 19 Sep 2013 16:13:54 -0400 Received: from e9.ny.us.ibm.com ([32.97.182.139]:34130) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VMkbh-0001PZ-0U for qemu-devel@nongnu.org; Thu, 19 Sep 2013 16:13:45 -0400 Received: from /spool/local by e9.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 19 Sep 2013 16:13:41 -0400 Received: from b01cxnp22035.gho.pok.ibm.com (b01cxnp22035.gho.pok.ibm.com [9.57.198.25]) by d01dlp01.pok.ibm.com (Postfix) with ESMTP id CD21238C8069 for ; Thu, 19 Sep 2013 16:13:32 -0400 (EDT) Received: from d01av02.pok.ibm.com (d01av02.pok.ibm.com [9.56.224.216]) by b01cxnp22035.gho.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r8JKDWdO49021154 for ; Thu, 19 Sep 2013 20:13:32 GMT Received: from d01av02.pok.ibm.com (loopback [127.0.0.1]) by d01av02.pok.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id r8JKDWno020459 for ; Thu, 19 Sep 2013 17:13:32 -0300 Message-ID: <523B5AE2.8000806@linux.vnet.ibm.com> Date: Thu, 19 Sep 2013 16:13:22 -0400 From: "Jason J. Herne" MIME-Version: 1.0 References: <1375366359-11553-1-git-send-email-jjherne@us.ibm.com> <52272B78.3010804@suse.de> <52285F8F.5020705@de.ibm.com> <52286A28.3070807@suse.de> In-Reply-To: <52286A28.3070807@suse.de> Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 8bit Subject: Re: [Qemu-devel] [PATCH 0/8] [PATCH RFC v3] s390 cpu hotplug Reply-To: jjherne@linux.vnet.ibm.com List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: =?ISO-8859-15?Q?Andreas_F=E4rber?= Cc: agraf@suse.de, ehabkost@redhat.com, qemu-devel@nongnu.org, "Jason J. Herne" , Christian Borntraeger , jfrei@linux.vnet.ibm.com, Anthony Liguori , imammedo@redhat.com, Luiz Capitulino , Einar Lueck On 09/05/2013 07:25 AM, Andreas Färber wrote: > Am 05.09.2013 12:40, schrieb Christian Borntraeger: >> On 04/09/13 14:45, Andreas Färber wrote: ... > To cope with device_add s390-cpu adding the device to > /machine/peripheral/ or /machine/peripheral-anon/device[0] I *think* > we'll need link<>, which would then translate back to ipi_states array > as backend and the remaining question would be where to expose those > properties in the composition tree - i.e. /machine/cpu[n] or > /machine/ipi/cpu[n] or something - please suggest. Similarly if those > become link<> properties then the CPUs created by the machine via > smp_cpus need a canonical path as well; quite obviously both cannot be > the same. > Ok, if I understand right then /machine/peripheral[-anon]/device[n] is the canonical path given to a a cpu that is created via qdev_device_add. We're going to create a link to that cpu via path /machine/cpu[cpu_addr]. I'm not sure what you meant by "if those become link<> properties then the CPUs created by the machine via smp_cpus need a canonical path as well". Wouldn't the canonical path just be /machine/peripheral[-anon]/device[n]? Are you saying we really want something different for non-hotplugged cpus? > Background is that long-term Anthony would like x86 CPU hot-plug to > become setting/unsetting some /machine/cpu-socket[n] link<> property of > the machine, and the ipi_states array seems a close equivalent on s390x. > >>> => Guest unaware of any emulated topology today. >> >> An additional problem is, that for the normal case (linux scheduler, no pinning, also >> no gang scheduling) the topology would change too fast. The guest would be busy rebuilding >> the scheduler domains all the time. > [snip] > > Regards, > Andreas > -- -- Jason J. Herne (jjherne@linux.vnet.ibm.com)