Re: [Qemu-devel] [PULL 2/7] tests/migration: Enable the migration test on s390x, too

[Thomas Huth]

On 2018-10-18 16:53, Wei Huang wrote:
> 
> 
> On 10/18/2018 07:43 AM, Emilio G. Cota wrote:
>> On Thu, Oct 18, 2018 at 14:38:01 +0200, Thomas Huth wrote:
>>> On 2018-10-17 21:28, Emilio G. Cota wrote:
>>>> Can anyone reproduce this? Otherwise, let me know what other info
>>>> I could provide.
>>>
>>> I've finally been able to reproduce it - seems like it only happens here
>>> when the host is under heavy load.
> 
> Given that it only happens under heavy load, could the failure be caused
> by migration thresholds defined in migrate_postcopy_prepare()? You can
> play with "max-bandwidth", "downtime-limit" and others to see if it helps.

David suggested on IRC yesterday that this problem might be the same as
with the ppc64 migration test: It does not work with TCG, only with KVM.

I've now done some tests, and indeed, I can not reproduce the problem
when running with KVM on a s390x host. But as soon as I disable the kvm
kernel module and run the test with TCG there, the problem occurs again.

So I think I'll send a patch to disable this test with TCG for now. Once
the problem with TCG has been solved, we can enable it again.

 Thomas