Re: [Xen-devel] Overhead incurred due to Xen for a page fault

[Dave Winchell <dwinchell@xxxxxxxxxxxxxxx>]

Fault path:

vmx_vmexit_handler
  vmx_do_page_fault
     shadow_fault (shadow_fault_64)

Put memory based trace code in shadow_fault_64, or, I presume, 
shadow_fault_32.
You'll see shadow_fault_64 get entered multiple times. I believe the 
faults are as
follows:
 1. The data page fault.
 2. The fault for the gos accessing the pte.
 3. The second fault for the data page.

This is for fully virtualized mode. I have not been looking at 
paravirtualized.
I see page fault times at 20-25 usec.

regards,
Dave



pak333@xxxxxxxxxxx wrote:

> I would like to get some help on estimating the cost of page fault 
> handling in Xen. Can someone help me identify where I need to put the 
> hooks into the xen source.
>  
> Thanks
> Kris
>
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