From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:38213) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UHWkF-0002iZ-Gm for qemu-devel@nongnu.org; Mon, 18 Mar 2013 05:52:47 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UHWkB-0000B2-Sq for qemu-devel@nongnu.org; Mon, 18 Mar 2013 05:52:43 -0400 Received: from mx1.redhat.com ([209.132.183.28]:13794) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UHWkB-0000Ao-Kq for qemu-devel@nongnu.org; Mon, 18 Mar 2013 05:52:39 -0400 Date: Mon, 18 Mar 2013 11:53:08 +0200 From: "Michael S. Tsirkin" Message-ID: <20130318095308.GD5267@redhat.com> References: <20130317090816.GB28528@redhat.com> <0c8d28e0-07d9-499f-920d-7ceca4155aab@mailpro> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <0c8d28e0-07d9-499f-920d-7ceca4155aab@mailpro> Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] slow virtio network with vhost=on and multiple cores List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Alexandre DERUMIER Cc: Peter Lieven , Stefan Hajnoczi , qemu-devel@nongnu.org, Davide Guerri , Jan Kiszka , Peter Lieven , Dietmar Maurer Do you see all interrupts going to the same CPU? If yes is irqbalance in guest running? On Mon, Mar 18, 2013 at 10:50:19AM +0100, Alexandre DERUMIER wrote: > Hello, about this bug, >=20 >=20 > Last Proxmox distrib use 2.6.32 rhel 6.3 kernel + qemu 1.4 , and have t= his problem with guest with 2.6.32 kernel. >=20 > do you think that +x2apic in guest cpu could help ? >=20 > (I think it's enable by default in RHEV/OVIRT ? but not in proxmox) >=20 >=20 >=20 > ----- Mail original ----- >=20 > De: "Michael S. Tsirkin" > =C0: "Peter Lieven" > Cc: "Davide Guerri" , "Alexandre DERUMIER" , "Stefan Hajnoczi" , qemu-devel@nongnu= .org, "Jan Kiszka" , "Peter Lieven" , "Dietmar Maurer" > Envoy=E9: Dimanche 17 Mars 2013 10:08:17 > Objet: Re: [Qemu-devel] slow virtio network with vhost=3Don and multipl= e cores >=20 > On Fri, Mar 15, 2013 at 08:23:44AM +0100, Peter Lieven wrote: > > On 15.03.2013 00:04, Davide Guerri wrote: > > >Yes this is definitely an option :) > > > > > >Just for curiosity, what is the effect of "in-kernel irqchip"? > > > > it emulates the irqchip in-kernel (in the KVM kernel module) which > > avoids userspace exits to qemu. in your particular case I remember > > that it made all IRQs deliverd to vcpu0 on. So I think this is a work= around > > and not the real fix. I think Michael is right that it is a > > client kernel bug. It would be good to find out what it is and ask > > the 2.6.32 maintainers to include it. i further have seen that > > with more recent kernels and inkernel-irqchip the irqs are delivered > > to vcpu0 only again (without multiqueue). > > > > >Is it possible to disable it on a "live" domain? > > > > try it. i don't know. you definetely have to do a live migration for = it,=20 > > but I have no clue if the VM will survice this. > > > > Peter >=20 > I doubt you can migrate VMs between irqchip/non irqchip configurations. >=20 > > > > > >Cheers, > > > Davide > > > > > > > > >On 14/mar/2013, at 19:21, Peter Lieven wrote: > > > > > >> > > >>Am 14.03.2013 um 19:15 schrieb Davide Guerri : > > >> > > >>>Of course I can do some test but a kernel upgrade is not an option= here :( > > >> > > >>disabling the in-kernel irqchip (default since 1.2.0) should also h= elp, maybe this is an option. > > >> > > >>Peter > > >> > > >> > > >