[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Xen-devel] [Patch] time resolution fix.
On 17 Mar 2006, at 14:39, Dong, Eddie wrote:
This patch fix HVM/VMX time resolution issue that cause IA32E complain
"loss tick" occationally and APIC time calibration issue.
not tested on SVM for slight common code change.
This patch looks scary. Can you give more info about the problem and
how you solve it? It looks like you end up forcibly sync'ing the
guest's TSC rate to the PIT rate? Would that even be necessary if the
PIT emulation were moved into Xen, where it ought to be?
On a slightly unrelated note, I think TSC rate management will start to
get exciting when we have HVM save/restore. What will happen if a guest
is restored on a machine with quite different TSC rate to the machine
it originally ran on? I was wondering whether the current TSC_OFFSET
feature that VMX supports might be extended to allow control over TSC
clock rate as well. For example, provide 'base' and 'scale' values and
apply following when guest executes RDTSC:
guest_tsc = (host_tsc - base) * scale + offset
How do you guys see this working?
Xen-devel mailing list