Vasiliy Tolstov
2015-Nov-27 13:25 UTC
Re: [libvirt-users] How to disable kvm_steal_time feature
27 нояб. 2015 г. 14:15 пользователь "Martin Kletzander" <mkletzan@redhat.com> написал:> > On Fri, Nov 20, 2015 at 04:31:56PM +0100, Piotr Rybicki wrote: >> >> Hi. >> >> I would like to workaround a bug, when after live-migration of KVM >> guest, there is a 100% steal time shown in guest. >> >> I've read, that disabling 'kvm_steal_time' feature should workarund >> this bug, but i can't find a way to disable it in libvirt's domain xml >> file. >> > > There is no support for that in libvirt. Either we must addit ad a > feature (patches welcome), but if that's there just for a workaround, > I would suggest chasing the original bug. > > If you just want to check that the workaround works, you could check > how the '-cpu ' parameter looks like when the domain is running and > then use the unsupported way of adding parameters to the qemu > commandline to specify the -cpu parameter again (qemu should use the > last one, so it should work), something like this: > > <domain type='kvm' xmlns:qemu='http://libvirt.org/schemas/domain/qemu/1.0'>> ... > <qemu:commandline> > <qemu:arg value='-cpu'/> > <qemu:arg value='${CPU_SPEC},-kvm_steal_time'/> > </qemu:commandline> > </domain> > > where ${CPU_SPEC} is the next parameter after the '-cpu' one from the > command line, so for qemu command line similar to this: > > qemu-kvm ... -cpu Nehalem,+feat,something ... > > the line in XML would be: > > <qemu:arg value='Nehalem,+feat,something,-kvm_steal_time'/> > > HTH, > > Martin > >> Tried in <cpu> section: >> <feature policy='disable' name='kvm_steal_time'/> >> but that doesn't work. >> >> Also, couldn't find any related information in libvirt documentation. >> Google helps neither. >> >> How can I disable this feature? >> >> Thanks in advance. >> Piotr Rybicki >> >>Does it possible to calculate steal time for vm if I have libvirt and domain stats? _______________________________________________>> libvirt-users mailing list >> libvirt-users@redhat.com >> https://www.redhat.com/mailman/listinfo/libvirt-users > > > _______________________________________________ > libvirt-users mailing list > libvirt-users@redhat.com > https://www.redhat.com/mailman/listinfo/libvirt-users
Martin Kletzander
2015-Nov-27 13:57 UTC
Re: [libvirt-users] How to disable kvm_steal_time feature
On Fri, Nov 27, 2015 at 04:25:55PM +0300, Vasiliy Tolstov wrote:>27 нояб. 2015 г. 14:15 пользователь "Martin Kletzander" <mkletzan@redhat.com> >написал: >> >> On Fri, Nov 20, 2015 at 04:31:56PM +0100, Piotr Rybicki wrote: >>> >>> Hi. >>> >>> I would like to workaround a bug, when after live-migration of KVM >>> guest, there is a 100% steal time shown in guest. >>> >>> I've read, that disabling 'kvm_steal_time' feature should workarund >>> this bug, but i can't find a way to disable it in libvirt's domain xml >>> file. >>> >> >> There is no support for that in libvirt. Either we must addit ad a >> feature (patches welcome), but if that's there just for a workaround, >> I would suggest chasing the original bug. >> >> If you just want to check that the workaround works, you could check >> how the '-cpu ' parameter looks like when the domain is running and >> then use the unsupported way of adding parameters to the qemu >> commandline to specify the -cpu parameter again (qemu should use the >> last one, so it should work), something like this: >> >> <domain type='kvm' xmlns:qemu='http://libvirt.org/schemas/domain/qemu/1.0 >'> >> ... >> <qemu:commandline> >> <qemu:arg value='-cpu'/> >> <qemu:arg value='${CPU_SPEC},-kvm_steal_time'/> >> </qemu:commandline> >> </domain> >> >> where ${CPU_SPEC} is the next parameter after the '-cpu' one from the >> command line, so for qemu command line similar to this: >> >> qemu-kvm ... -cpu Nehalem,+feat,something ... >> >> the line in XML would be: >> >> <qemu:arg value='Nehalem,+feat,something,-kvm_steal_time'/> >> >> HTH, >> >> Martin >> >>> Tried in <cpu> section: >>> <feature policy='disable' name='kvm_steal_time'/> >>> but that doesn't work. >>> >>> Also, couldn't find any related information in libvirt documentation. >>> Google helps neither. >>> >>> How can I disable this feature? >>> >>> Thanks in advance. >>> Piotr Rybicki >>> >>> > >Does it possible to calculate steal time for vm if I have libvirt and >domain stats?I don't think we report that in domain stats, but top/virt-top could help with that.>_______________________________________________ >>> libvirt-users mailing list >>> libvirt-users@redhat.com >>> https://www.redhat.com/mailman/listinfo/libvirt-users >> >> >> _______________________________________________ >> libvirt-users mailing list >> libvirt-users@redhat.com >> https://www.redhat.com/mailman/listinfo/libvirt-users
Vasiliy Tolstov
2015-Nov-27 14:47 UTC
Re: [libvirt-users] How to disable kvm_steal_time feature
2015-11-27 16:57 GMT+03:00 Martin Kletzander <mkletzan@redhat.com>:> I don't think we report that in domain stats, but top/virt-top could > help with that.Ok libvirt can't get this value, but does it possible if i know cpu stats of domain and host info (i don't know which =)) determine for specific domain does it possible have steal time or not? -- Vasiliy Tolstov, e-mail: v.tolstov@selfip.ru