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From: Dave Winchell <dwinchell@virtualiron.com>
To: pak333@comcast.net
Cc: xen-devel@lists.xensource.com
Subject: Re: Overhead incurred due to Xen for a page fault
Date: Fri, 24 Mar 2006 10:27:33 -0500	[thread overview]
Message-ID: <44240FE5.9090902@virtualiron.com> (raw)
In-Reply-To: <032420060427.4189.442375210007CE670000105D2207024553CCCCCC050E9F@comcast.net>

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@comcast.net 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
>
>------------------------------------------------------------------------
>
>_______________________________________________
>Xen-devel mailing list
>Xen-devel@lists.xensource.com
>http://lists.xensource.com/xen-devel
>  
>

  parent reply	other threads:[~2006-03-24 15:27 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-03-24  4:27 Overhead incurred due to Xen for a page fault pak333
2006-03-24  7:00 ` Randy Thelen
2006-03-24 15:27 ` Dave Winchell [this message]
  -- strict thread matches above, loose matches on Subject: below --
2006-03-28  0:07 pak333

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