Re: xen 4.14.3 incorrect (~3x) cpu frequency reported

[James Dingwall <james-xen@xxxxxxxxxxxxxx>]

Hi Jan,

> > On Wed, Jul 21, 2021 at 12:59:11PM +0200, Jan Beulich wrote:                
> >                                                             
> >> On 21.07.2021 11:29, James Dingwall wrote:                                 
> >>                                                             
> >>> We have a system which intermittently starts up and reports an incorrect 
> >>> cpu frequency:                                               
...
> > I'm sorry to ask, but have you got around to actually doing that? Or
> > else is resolving this no longer of interest?

We have experienced an occurence of this issue on 4.14.3 with 'loglvl=all'
present on the xen command line.  I have attached the 'xl dmesg' output for
the fast MHz boot, the diff from the normal case is small so I've not added
that log separately:

--- normal-mhz/xl-dmesg.txt     2022-01-06 14:13:47.231465234 +0000
+++ funny-mhz/xl-dmesg.txt      2022-01-06 13:45:43.825148510 +0000
@@ -211,7 +211,7 @@
 (XEN)  cap enforcement granularity: 10ms
 (XEN) load tracking window length 1073741824 ns
 (XEN) Platform timer is 24.000MHz HPET
-(XEN) Detected 2294.639 MHz processor.
+(XEN) Detected 7623.412 MHz processor.
 (XEN) EFI memory map:
 (XEN)  0000000000000-0000000007fff type=3 attr=000000000000000f
 (XEN)  0000000008000-000000003cfff type=7 attr=000000000000000f
@@ -616,6 +616,7 @@
 (XEN) PCI add device 0000:b7:00.1
 (XEN) PCI add device 0000:b7:00.2
 (XEN) PCI add device 0000:b7:00.3
+(XEN) Platform timer appears to have unexpectedly wrapped 10 or more times.
 (XEN) [VT-D]d0:PCIe: unmap 0000:65:00.2
 (XEN) [VT-D]d32753:PCIe: map 0000:65:00.2
 (XEN) [VT-D]d0:PCIe: unmap 0000:65:00.1

I also have the dom0 kernel dmesg available if that would be useful but I've
left it off initially because the log is quite large.  I don't see much in
the diff between boots except where speed/times are reported and where things
are initialised in a slightly different order.

Thanks,
James

Attachment: xl-dmesg.txt
Description: Text document