WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

Re: [Xen-devel] Re: Getting the page fault count for domU

At 06:37 -0700 on 03 Oct (1317623870), Chintamani Siddeshwar wrote:
> I am interested in counting the number of page-faults in the guest -
> page-faults that result in a disk I/O.

You will have to do that from inside the guest - only the guest's OS
knows which of its page-faults result in I/O, and on modern (EPT/RVI)
hardware, Xen doesn't even see most guest page-faults.

> Also when would XEN tools page a guest memory to disk? Is it a manual
> process (by running "xenpaging" command) or is it a performance enhancement
> added in recent versions of XEN?

Only when the xenpaging daemon is running.  It is definitely not a
performance enhancement (memory pressure is better dealt with by the
guest) but is useful as a backstop if you're overcommitting memory some
other way.

Tim.

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel