RE: [Xen-devel] Re: [PATCH 3/5] x86/pvclock: add vsyscall implementation

Dan Magenheimer
2009-10-07T22:40:12Z

> Then they will get incorrect timing once they are live migrated.

I've posted a proposed (OS-independent) solution for that and
am (slowly) in the process of implementing it.

> -----Original Message-----
> From: Avi Kivity [mailto:avi@redhat.com]
> Sent: Wednesday, October 07, 2009 3:08 PM
> To: Dan Magenheimer
> Cc: Jeremy Fitzhardinge; Jeremy Fitzhardinge; Xen-devel; Kurt Hackel;
> the arch/x86 maintainers; Linux Kernel Mailing List; Glauber
> de Oliveira
> Costa; Keir Fraser; Zach Brown; Chris Mason
> Subject: Re: [Xen-devel] Re: [PATCH 3/5] x86/pvclock: add vsyscall
> implementation
>
>
> On 10/07/2009 10:48 PM, Dan Magenheimer wrote:
> >> We can support them by falling back to the kernel. I'm a
> bit worried
> >> about the kernel playing with the hypervisor's version field. It's
> >> better to introduce yet a new version for the kernel, and
> check both.
> >>
> > On Nehalem, apps that need timestamp information at a high
> > frequency will likely use rdtsc/rdtscp directly.
> >
> >
>
> Then they will get incorrect timing once they are live migrated.
>
> --
> I have a truly marvellous patch that fixes the bug which this
> signature is too narrow to contain.
>
>
>