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Re: [Qemu-devel] [PATCH] kvmclock: Ensure time in migration never goes b
Re: [Qemu-devel] [PATCH] kvmclock: Ensure time in migration never goes backward
Mon, 5 May 2014 20:31:48 -0300
Can you provide detailed instructions on how to reproduce the problem?
On Mon, May 05, 2014 at 08:27:10PM -0300, Marcelo Tosatti wrote:
> On Mon, May 05, 2014 at 08:26:04PM +0200, Marcin Gibuła wrote:
> > >>is it possible to have kvmclock jumping forward?
> > >>
> > >>Because I've reproducible case when at about 1 per 20 vm restores, VM
> > >>freezes for couple of hours and then resumes with date few hundreds years
> > >>ahead. Happens only with kvmclock.
> > >>
> > >>And this patch seems to fix very similar issue so maybe it's all the same
> > >>bug.
> > >
> > >I'm fairly sure it is the exact same bug. Jumping backward is like jumping
> > >forward by a biiiiig amount :)
> > Hi,
> > I've tested your path on my test VM... don't know if it's pure luck
> > or not, but it didn't hang with over 70 restores.
> > The message "KVM Clock migrated backwards, using later time" fires
> > every time, but VM is healthy after resume.
> What is the host clocksource? (cat
> And kernel version?
Re: [Qemu-devel] [PATCH] kvmclock: Ensure time in migration never goes backward, Marcelo Tosatti, 2014/05/05