Re: [openstack-dev] [nova][libvirt] The None and 'none' for CONF.libvirt.cpu_mode
> -Original Message- > From: Daniel P. Berrange [mailto:berra...@redhat.com] > Sent: Wednesday, March 4, 2015 9:56 AM > To: Jiang, Yunhong > Cc: openstack-dev@lists.openstack.org; Xu, Hejie > Subject: Re: [nova][libvirt] The None and 'none' for CONF.libvirt.cpu_mode > > On Wed, Mar 04, 2015 at 05:24:53PM +, Jiang, Yunhong wrote: > > Daniel, thanks for your clarification. > > > > Another related question is, what will be the guest's real cpu model > > is the cpu_model is None? This is about a reported regression at > > The guest CPU will be unspecified - it will be some arbitrary > hypervisor decided default which nova cannot know. > > > https://bugs.launchpad.net/nova/+bug/1082414 . When the > > instance.vcpu_model.mode is None, we should compare the source/target > > cpu model, as the suggestion from Tony, am I right? > > If CPU model is none, best we can do is compare the *host* CPU of > the two hosts to make sure the host doesn't loose any features, as > we have no way of knowing what features the guest is relying on. Thanks for clarification. I will cook a patch for this issue. --jyh > > Regards, > Daniel > -- > |: http://berrange.com -o-http://www.flickr.com/photos/dberrange/ :| > |: http://libvirt.org -o- http://virt-manager.org :| > |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| > |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :| __ OpenStack Development Mailing List (not for usage questions) Unsubscribe: openstack-dev-requ...@lists.openstack.org?subject:unsubscribe http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
Re: [openstack-dev] [nova][libvirt] The None and 'none' for CONF.libvirt.cpu_mode
On Wed, Mar 04, 2015 at 05:24:53PM +, Jiang, Yunhong wrote: > Daniel, thanks for your clarification. > > Another related question is, what will be the guest's real cpu model > is the cpu_model is None? This is about a reported regression at The guest CPU will be unspecified - it will be some arbitrary hypervisor decided default which nova cannot know. > https://bugs.launchpad.net/nova/+bug/1082414 . When the > instance.vcpu_model.mode is None, we should compare the source/target > cpu model, as the suggestion from Tony, am I right? If CPU model is none, best we can do is compare the *host* CPU of the two hosts to make sure the host doesn't loose any features, as we have no way of knowing what features the guest is relying on. Regards, Daniel -- |: http://berrange.com -o-http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :| __ OpenStack Development Mailing List (not for usage questions) Unsubscribe: openstack-dev-requ...@lists.openstack.org?subject:unsubscribe http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
Re: [openstack-dev] [nova][libvirt] The None and 'none' for CONF.libvirt.cpu_mode
Daniel, thanks for your clarification. Another related question is, what will be the guest's real cpu model is the cpu_model is None? This is about a reported regression at https://bugs.launchpad.net/nova/+bug/1082414 . When the instance.vcpu_model.mode is None, we should compare the source/target cpu model, as the suggestion from Tony, am I right? Thanks --jyh > -Original Message- > From: Daniel P. Berrange [mailto:berra...@redhat.com] > Sent: Wednesday, March 4, 2015 6:56 AM > To: Jiang, Yunhong > Cc: openstack-dev@lists.openstack.org; Xu, Hejie > Subject: Re: [nova][libvirt] The None and 'none' for CONF.libvirt.cpu_mode > > On Wed, Mar 04, 2015 at 02:52:06PM +, Jiang, Yunhong wrote: > > Hi, Daniel > > I'm a bit confused of the None/'none' for CONF.libvirt.cpu_mode. > Per my understanding, None means there is no configuration provided and > libvirt will select the default value based on the virt_type, none means no > cpu_mode information should be provided. For the guest, am I right? > > > > In _get_guest_cpu_model_config() on virt/libvirt/driver.py, > > if mode is 'none', kvm/qemu virt_type will return a > > vconfig.LibvirtConfigGuestCPU() while other virt type will return None. > > What's the difference of this return difference? > > The LibvirtConfigGuestCPU object is used for more than just configuring > the CPU model. It is also used for expressing CPU topology (sockets, cores, > threads) and NUMA topology. So even if cpu model is None, we still need > that object in the kvm case. > > Regards, > Daniel > -- > |: http://berrange.com -o-http://www.flickr.com/photos/dberrange/ :| > |: http://libvirt.org -o- http://virt-manager.org :| > |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| > |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :| __ OpenStack Development Mailing List (not for usage questions) Unsubscribe: openstack-dev-requ...@lists.openstack.org?subject:unsubscribe http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
Re: [openstack-dev] [nova][libvirt] The None and 'none' for CONF.libvirt.cpu_mode
On Wed, Mar 04, 2015 at 02:52:06PM +, Jiang, Yunhong wrote: > Hi, Daniel > I'm a bit confused of the None/'none' for CONF.libvirt.cpu_mode. Per my > understanding, None means there is no configuration provided and libvirt will > select the default value based on the virt_type, none means no cpu_mode > information should be provided. For the guest, am I right? > > In _get_guest_cpu_model_config() on virt/libvirt/driver.py, > if mode is 'none', kvm/qemu virt_type will return a > vconfig.LibvirtConfigGuestCPU() while other virt type will return None. > What's the difference of this return difference? The LibvirtConfigGuestCPU object is used for more than just configuring the CPU model. It is also used for expressing CPU topology (sockets, cores, threads) and NUMA topology. So even if cpu model is None, we still need that object in the kvm case. Regards, Daniel -- |: http://berrange.com -o-http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :| __ OpenStack Development Mailing List (not for usage questions) Unsubscribe: openstack-dev-requ...@lists.openstack.org?subject:unsubscribe http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
[openstack-dev] [nova][libvirt] The None and 'none' for CONF.libvirt.cpu_mode
Hi, Daniel I'm a bit confused of the None/'none' for CONF.libvirt.cpu_mode. Per my understanding, None means there is no configuration provided and libvirt will select the default value based on the virt_type, none means no cpu_mode information should be provided. For the guest, am I right? In _get_guest_cpu_model_config() on virt/libvirt/driver.py, if mode is 'none', kvm/qemu virt_type will return a vconfig.LibvirtConfigGuestCPU() while other virt type will return None. What's the difference of this return difference? Thanks --jyh __ OpenStack Development Mailing List (not for usage questions) Unsubscribe: openstack-dev-requ...@lists.openstack.org?subject:unsubscribe http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
