[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Xen-devel] [PATCH 0/2] Viridian MSRs



>>> On 15.10.13 at 20:12, Andrew Cooper <andrew.cooper3@xxxxxxxxxx> wrote:
> This set of two patches advertises 3 constant, read-only MSRs of timing
> information to a viridian capable VM.
> 
> There is an as-yet-unidentified issue when running Windows 8.1 / Server 2012r2
> under Xen where it will periodically (1 in 10 attempt) appear to fall into 
> an
> idle loop rather than schedule userspace processes (such as failing to run a
> login session).
> 
> I am still investigating the underlying cause.  One possibility is an
> interaction of TSC time calibration interacting poorly with the Xen 
> scheduler.
> 
> Unfortunately, attempting to divine what windows is unhappy about with its
> environment is rather tricky (even a BSOD would be more useful than the
> current symptoms), but providing these MSRs causes Windows to prefer rdtsc
> over the HPET main counter as a source of time, and 'fixes' the above issue.
> 
> CC: Paul Durrant <paul.durrant@xxxxxxxxxx>

I was kind of expecting to get a Reviewed-by (or other comments)
from you on this - is there any hope for this to be happening at
some point?

Thanks, Jan


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel


 


Rackspace

Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.