[fedora-virt] is there a best clock to use?

Tom Horsley tom.horsley at att.net
Thu Jan 21 12:42:21 UTC 2010


On Thu, 21 Jan 2010 10:18:38 -0200
Glauber Costa wrote:

> On Wed, Jan 20, 2010 at 08:42:30PM -0500, Tom Horsley wrote:
> > Is there a HOWTO anywhere of the different ways to
> > make time of day clock work in virtual machines and different
> > ways to influence it from the qemu side of the world?
> > 
> > Time keeping is horrible in most of my virtual machines,
> > and I just wonder if there are settings I can change
> > in libvirt or kernel boot parameters I can apply in
> > the linux guest to make things slightly less horrible?
> > 
> It basically depends on your guest. What guests are we
> talking about here?
> 
> If you run a fairly recent linux (that has pvclock), you
> should have no issues.

I run gazillions of different linux distros, primarily to
test our software on lots of different platforms, so
there are a wide variety of different versions of linux
from old to new. And in fact, time isn't horrible on
all of them, just on some of them.

Even in an old linux I have trouble understanding how
the time can be 200 seconds off as soon as it is booted :-).


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