Xen devel - Apr 2007 - Where is xtime updated in a domU with an independent wallclock?

Hi All,

I have just started looking at the code for Xen so please bear with me.

A domU Linux kernel running with independent_wallclock=1 seems to sync 
its time with dom0 after every "xm unpause" (obviously preceded by an 
"xm pause").

I don''t see where the xtime variable is being updated after an "xm
unpause", i.e., domain_unpause_by_systemcontroller(). Right after the 
unpause, it seems to me that the xtime in the domU should be what it 
were just prior to the pause.

Any response would be greatly appreciated.

Cheers,
Jay.


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Hi All,

I have just started looking at the code for Xen so please bear with me.

A domU Linux kernel running with independent_wallclock=1 seems to sync
its time with dom0 after every "xm unpause" (obviously preceded by an
"xm pause").

I don''t see where the xtime variable is being updated after an "xm
unpause", i.e., domain_unpause_by_systemcontroller(). Right after the
unpause, it seems to me that the xtime in the domU should be what it
were just prior to the pause.

Any response would be greatly appreciated.

Cheers,
Jay.



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

Hi All,

I have just started looking at the code for Xen so please bear with me.

A domU Linux kernel running with independent_wallclock=1 seems to sync
its time with dom0 after every "xm unpause" (obviously preceded by an
"xm pause").

I don''t see where the xtime variable is being updated after an "xm
unpause", i.e., domain_unpause_by_systemcontroller(). Right after the
unpause, it seems to me that the xtime in the domU should be what it
were just prior to the pause.

Any response would be greatly appreciated.

Cheers,
Jay.

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

Hi All,

I have just started looking at the code for Xen so please bear with me.

A domU Linux kernel running with independent_wallclock=1 seems to sync
its time with dom0 after every "xm unpause" (obviously preceded by an
"xm pause").

I don''t see where the xtime variable is being updated after an "xm
unpause", i.e., domain_unpause_by_systemcontroller(). Right after the
unpause, it seems to me that the xtime in the domU should be what it
were just prior to the pause.

Any response would be greatly appreciated.

Cheers,

Jay.



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

Hi All,
 I have just started looking at the code for Xen so please bear with me.
 A domU Linux kernel running with independent_wallclock=1 seems to sync its 
time with dom0 after every "xm unpause" (obviously preceded by an
"xm  pause").
 I don''t see where the xtime variable is being updated after an
"xm unpause",  i.e., domain_unpause_by_systemcontroller(). Right after
the unpause, it seems to  me that the xtime in the domU should be what it were
just prior to the  pause.
 Any response would be greatly appreciated.
 Cheers,
 Jay.

   
       
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On 2/5/07 07:41, "Jay Patel" <nitrofin@yahoo.com> wrote:
> I have just started looking at the code for Xen so please bear with me.
>  
> A domU Linux kernel running with independent_wallclock=1 seems to sync its
> time with dom0 after every "xm unpause" (obviously preceded by an
"xm
> pause").
>  
> I don''t see where the xtime variable is being updated after an
"xm unpause",
> i.e., domain_unpause_by_systemcontroller(). Right after the unpause, it
seems
> to  me that the xtime in the domU should be what it were just prior to the
> pause.
Yes, a guest with independent wallclock should never sync with the wallclock
time record provided by Xen, even after an unpause (the unpause is not
explicitly visible to the guest anyway).

 -- Keir



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Keir Fraser <Keir.Fraser@cl.cam.ac.uk> wrote:Re: [Xen-devel] Where is
xtime updated in a domU with an independent wallclock?
 
 
 On 2/5/07 07:41, "Jay Patel" <nitrofin@yahoo.com> wrote:
 
 I have just started looking at the code for Xen so please bear with me.
  
 A domU Linux kernel running with independent_wallclock=1 seems to sync its 
time with dom0 after every "xm unpause" (obviously preceded by an
"xm  pause").
  
 I don''t see where the xtime variable is being updated after an
"xm unpause",  i.e., domain_unpause_by_systemcontroller(). Right after
the unpause, it seems to  me that the xtime in the domU should be what it were
just prior to the  pause.
 
 Yes, a guest with independent wallclock should never sync with the wallclock
time record provided by Xen, even after an unpause (the unpause is not
explicitly visible to the guest anyway).
 
  -- Keir
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http://lists.xensource.com/xen-devel


       
---------------------------------
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 Check outnew cars at Yahoo! Autos.

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