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SubjectRe: [Xen-devel] [PATCH] xen: always set the sched clock as unstable
On 16/04/12 17:05, Dan Magenheimer wrote:
>> From: David Vrabel [mailto:david.vrabel@citrix.com]
>> Subject: Re: [Xen-devel] [PATCH] xen: always set the sched clock as unstable
>
> Nacked-by: Dan Magenheimer <dan.magenheimer@oracle.com>

Fair enough,

> [A stable clock] should be true for Xen 4.0+ (but not for pre-Xen-4.0).

The original customer problem is on a host with Xen 3.4. What do you
recommend for Linux guests running such hosts?

> In fact, it might be wise for a Xen-savvy kernel to check to see
> if it is running on Xen-4.0+ and, if so, force clocksource=tsc
> and tsc=reliable.

So, should the xen clocksource do:

if Xen 4.0+
clock is stable, use rdtsc only.
else
clock is unstable, use existing pvclock implementation.

David


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