RE: about the time consuming kvm_vcpu_ioctl issue in rhel kernel
Please Ignore the following message in the brace
{ The synchronize_rcu() is a time consuming operation, the unpstream kernel
still have some issue, the KVM_RUN ioctl will take more then 10ms when
resume the VM after migration. }
The upstream kernel does not have such issue, only the rhel kernel has. Forgive
my neglect.
Liang
>
>
> > -Original Message-
> > From: Li, Liang Z
> > Sent: Thursday, August 06, 2015 11:47 AM
> > To: 'Paolo Bonzini'; 'Juan Quintela'; linux-kernel@vger.kernel.org
> > Cc: Zhang, Yang Z; k...@vger.kernel.org
> > Subject: about the time consuming kvm_vcpu_ioctl issue in rhel kernel
> >
> > Hi Paolo & Juan,
> >
> > I found some of the kvm_vcpu_ioctl operation takes about more than
> > 10ms with the 3.10.0-229.el7.x86_64 kernel, which prolong the VM
> > service downtime when doing live migration about 20~30ms.
> > This happened when doing the KVM_KVMCLOCK_CTRL ioctl. It's worse if
> > more VCPUs used by guest(4VPUs in my test). The upstream kernel does
> > not have this issue because of the patch 7a72f7a140bfd3, maybe this
> > patch should be backported to the el7 kernel.
> >
> > Liang
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RE: about the time consuming kvm_vcpu_ioctl issue in rhel kernel
Please Ignore the following message in the brace
{ The synchronize_rcu() is a time consuming operation, the unpstream kernel
still have some issue, the KVM_RUN ioctl will take more then 10ms when
resume the VM after migration. }
The upstream kernel does not have such issue, only the rhel kernel has. Forgive
my neglect.
Liang
-Original Message-
From: Li, Liang Z
Sent: Thursday, August 06, 2015 11:47 AM
To: 'Paolo Bonzini'; 'Juan Quintela'; linux-kernel@vger.kernel.org
Cc: Zhang, Yang Z; k...@vger.kernel.org
Subject: about the time consuming kvm_vcpu_ioctl issue in rhel kernel
Hi Paolo Juan,
I found some of the kvm_vcpu_ioctl operation takes about more than
10ms with the 3.10.0-229.el7.x86_64 kernel, which prolong the VM
service downtime when doing live migration about 20~30ms.
This happened when doing the KVM_KVMCLOCK_CTRL ioctl. It's worse if
more VCPUs used by guest(4VPUs in my test). The upstream kernel does
not have this issue because of the patch 7a72f7a140bfd3, maybe this
patch should be backported to the el7 kernel.
Liang
--
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
RE: about the time consuming kvm_vcpu_ioctl issue in rhel kernel
The synchronize_rcu() is a time consuming operation, the unpstream kernel still have some issue, the KVM_RUN ioctl will take more then 10ms when resume the VM after migration. Liang > -Original Message- > From: Li, Liang Z > Sent: Thursday, August 06, 2015 11:47 AM > To: 'Paolo Bonzini'; 'Juan Quintela'; linux-kernel@vger.kernel.org > Cc: Zhang, Yang Z; k...@vger.kernel.org > Subject: about the time consuming kvm_vcpu_ioctl issue in rhel kernel > > Hi Paolo & Juan, > > I found some of the kvm_vcpu_ioctl operation takes about more than 10ms > with the 3.10.0-229.el7.x86_64 kernel, which prolong the VM service > downtime when doing live migration about 20~30ms. > This happened when doing the KVM_KVMCLOCK_CTRL ioctl. It's worse if > more VCPUs used by guest(4VPUs in my test). The upstream kernel does not > have this issue because of the patch 7a72f7a140bfd3, maybe this patch > should be backported to the el7 kernel. > > Liang -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
about the time consuming kvm_vcpu_ioctl issue in rhel kernel
Hi Paolo & Juan, I found some of the kvm_vcpu_ioctl operation takes about more than 10ms with the 3.10.0-229.el7.x86_64 kernel, which prolong the VM service downtime when doing live migration about 20~30ms. This happened when doing the KVM_KVMCLOCK_CTRL ioctl. It's worse if more VCPUs used by guest(4VPUs in my test). The upstream kernel does not have this issue because of the patch 7a72f7a140bfd3, maybe this patch should be backported to the el7 kernel. Liang -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
RE: about the time consuming kvm_vcpu_ioctl issue in rhel kernel
The synchronize_rcu() is a time consuming operation, the unpstream kernel still have some issue, the KVM_RUN ioctl will take more then 10ms when resume the VM after migration. Liang -Original Message- From: Li, Liang Z Sent: Thursday, August 06, 2015 11:47 AM To: 'Paolo Bonzini'; 'Juan Quintela'; linux-kernel@vger.kernel.org Cc: Zhang, Yang Z; k...@vger.kernel.org Subject: about the time consuming kvm_vcpu_ioctl issue in rhel kernel Hi Paolo Juan, I found some of the kvm_vcpu_ioctl operation takes about more than 10ms with the 3.10.0-229.el7.x86_64 kernel, which prolong the VM service downtime when doing live migration about 20~30ms. This happened when doing the KVM_KVMCLOCK_CTRL ioctl. It's worse if more VCPUs used by guest(4VPUs in my test). The upstream kernel does not have this issue because of the patch 7a72f7a140bfd3, maybe this patch should be backported to the el7 kernel. Liang -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
about the time consuming kvm_vcpu_ioctl issue in rhel kernel
Hi Paolo Juan, I found some of the kvm_vcpu_ioctl operation takes about more than 10ms with the 3.10.0-229.el7.x86_64 kernel, which prolong the VM service downtime when doing live migration about 20~30ms. This happened when doing the KVM_KVMCLOCK_CTRL ioctl. It's worse if more VCPUs used by guest(4VPUs in my test). The upstream kernel does not have this issue because of the patch 7a72f7a140bfd3, maybe this patch should be backported to the el7 kernel. Liang -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
