From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1MN77I-00030D-As for qemu-devel@nongnu.org; Sat, 04 Jul 2009 11:25:28 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1MN77D-0002zt-Ol for qemu-devel@nongnu.org; Sat, 04 Jul 2009 11:25:28 -0400 Received: from [199.232.76.173] (port=57485 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1MN77D-0002zq-JP for qemu-devel@nongnu.org; Sat, 04 Jul 2009 11:25:23 -0400 Received: from mx2.redhat.com ([66.187.237.31]:43943) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1MN77D-0001W0-4s for qemu-devel@nongnu.org; Sat, 04 Jul 2009 11:25:23 -0400 Message-ID: <4A4F745C.8010001@redhat.com> Date: Sat, 04 Jul 2009 18:25:16 +0300 From: Avi Kivity MIME-Version: 1.0 References: <1246632116-31366-1-git-send-email-andre.przywara@amd.com> In-Reply-To: <1246632116-31366-1-git-send-email-andre.przywara@amd.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Subject: [Qemu-devel] Re: [RFC] allow multi-core guests: introduce cores= option to -cpu List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Andre Przywara Cc: qemu-devel@nongnu.org, kvm@vger.kernel.org On 07/03/2009 05:41 PM, Andre Przywara wrote: > Hi, > > currently SMP guests happen to see vCPUs as different sockets. > Some guests (Windows comes to mind) have license restrictions and refuse > to run on multi-socket machines. > So lets introduce a "cores=" parameter to the -cpu option to let the user > specify the number of _cores_ the guest should see. > > This patch has not been tested with all corner cases, so I just want to > hear your comments whether > a) we need such an option and > b) you like this particular approach. > > Applying this qemu.git patch to qemu-kvm.git fixes Windows SMP boot on > some versions, I successfully tried up to -smp 16 -cpu host,cores=8 with > WindowsXP Pro. > > I thought of using -smp [processors=]2,cores=4,threads=2 (for a total of 16 threads), but I think it makes more sense with -cpu. -- Do not meddle in the internals of kernels, for they are subtle and quick to panic.