Re: [Qemu-devel] live migration between amd fam15h-fam10h

[Brian Jackson]

On 01/27/2014 08:20 AM, Markus Kovero wrote:
>> Hi,
>>
>> I am getting a frozen guest when migrating from an Opteron 6274 host
>> (amd
>> fam15h) to
>> an Opteron 6174 host (amd fam10h). The live migration completes
>> succesfully, but
>> the guest is frozen: vcn screen is still there, but no input is
>> possible and
>> no kernel output is seen. Trying "c" on the qemu-monitor does not help.
>> I am using "-cpu Opteron_G3" which I assumed would be ok for both
>> host cpus.
>>
>> In the opposite direction (migrating from an amd fam10h host to an
>> amdfam15h
>> host) the guest continues to run on the destination. However, on most
>> of these
>> successfull live migrations, I notice a "clocksource unstable"
>> message on the
>> guest kernel (using the default kvm-clock clocksource) e.g.
>> Clocksource tsc unstable (delta = -1500533439 ns)
>> Same situation (guest runs on destination with clocksource unstable
>> message)
>> happens when migrating between fam15h hosts (I have not tried between
>> fam10h
>> hosts)
>>
>> Changing the clocksource (tsc, acpi_pm, hpet) does not solve the issue.
>> Also tried with "-cpu kvm64" with same result.
>>
>> qemu-kvm version: 0.15.1, 1.0 or qemu-kvm/master
>> Host kernel: 3.0.15 (on both hosts)
>> Guest kernel: 3.0.6 or 3.2
>>
>> this is the qemu-kvm command line used on the source host:
>>
>> "
>> kvm -enable-kvm -m 1024 -smp 1 -cpu Opteron_G3,check -drive \
>>
>> file=/opt/test.img,if=none,id=drive-virtio-disk1,format=raw,cache=writethrough,boot=on
>>
>> -device
>>
>> virtio-blk-pci,bus=pci.0,addr=0x5,drive=drive-virtio-disk1,id=virtio-disk1
>>
>> -monitor stdio -vnc 0.0.0.0:6 -vga std -chardev pty,id=charserial0
>> -device
>> isa-serial,chardev=charserial0,id=serial0 -usb -device
>> usb-tablet,id=input0
>> "
>>
>> The destination host has the same command line with an added "-incoming
>> tcp:4444". I have mainly tested this with non-shared storage (but
>> also shared
>> storage has the same result). Migration is triggered with "migrate -b
>> tcp:destip:4444"
>>
>> Do the TSC microarchitecture changes in amdfam15h (see AMD SW
>> optimiization
>> guide for fam15h, 47414 Rev 3.02 Appendix E) affect pvclock stability on
>> migration in same family or across families?
>>
>> cpuid information follows in case it's helpful.
> ..snip..
>
>
> Hi, I can confirm this problem still exists in live migrations between
> Opteron 6128HE and Opteron 6274.
> Live migration from 6100-series to 6200-series work, but never from
> 6200 to 6100.
> Issue is reproducible and symptoms are identical with previous poster.
> I have tested with 3.10.5 host-kernel and 1.7 qemu, also with 3.1.4
> and >1.0 qemu, guest kernel seems to be irrelevant at this point (as
> it crashes any OS).
>
> I would say this needs attention, and I'm willing to help to get this
> sorted out.


Did it ever work? If so, I'd start by git bisecting to find out where it
broke.


>
> Thanks for your thoughts.
>
> Yours
> Markus Kovero
> +358 40 577 1129
>