Is this a bug of xentrace?

Is this a bug of xentrace?

[Hui Kang]

Hi,
I am using xentrace to trace the events of guest domains on a host 
physical machine.  In the parsed trace file,
if the guest domain is created on the host machine, then the entry is good
switch_infprev    [ old_domid = 0x00000002
// the guest domain has a id of 2.
switch_infnext    [ new_domid = 0x00000000

However, if the guest domain is migrated from another host machine,  the 
parsed trace file shows
switch_infprev    [ old_domid = 0x00007ffff
// the guest domain has a id of 2.
switch_infnext    [ new_domid = 0x00000000
Even the domain Id is 2, it shows 0x00007ffff.
Can anyone explain this? Thanks.

Re: Is this a bug of xentrace?

[George Dunlap]

Are you sure that's not 0x7fff? (Three f's, not four?)  0x7fff is the
domain ID of the idle domain (scheduled when there is no other work on
the system to do).

 -George

On Sat, May 9, 2009 at 7:56 PM, Hui Kang <hkang@cs.sunysb.edu> wrote:
> Hi,
> I am using xentrace to trace the events of guest domains on a host physical
> machine.  In the parsed trace file,
> if the guest domain is created on the host machine, then the entry is good
> switch_infprev    [ old_domid = 0x00000002
> // the guest domain has a id of 2.
> switch_infnext    [ new_domid = 0x00000000
>
> However, if the guest domain is migrated from another host machine,  the
> parsed trace file shows
> switch_infprev    [ old_domid = 0x00007ffff
> // the guest domain has a id of 2.
> switch_infnext    [ new_domid = 0x00000000
> Even the domain Id is 2, it shows 0x00007ffff.
> Can anyone explain this? Thanks.
>
>
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel
>

Re: Is this a bug of xentrace?

[Hui Kang]

Yes, it is 0x00007fff. This is one line  in the parsed trace file.
CPU1  962569711226060 (+     574)  switch_infnext    [ new_domid = 
0x00007fff, time = 14321, r_time =30000000 ]
When I use "xm list", it shows the domain id is 5. There are only two 
domains on the host.
Can any one point out what does "0x00007fff" this number mean? Thanks.

- Hui

George Dunlap wrote:
> Are you sure that's not 0x7fff? (Three f's, not four?)  0x7fff is the
> domain ID of the idle domain (scheduled when there is no other work on
> the system to do).
>
>  -George
>
> On Sat, May 9, 2009 at 7:56 PM, Hui Kang <hkang@cs.sunysb.edu> wrote:
>   
>> Hi,
>> I am using xentrace to trace the events of guest domains on a host physical
>> machine.  In the parsed trace file,
>> if the guest domain is created on the host machine, then the entry is good
>> switch_infprev    [ old_domid = 0x00000002
>> // the guest domain has a id of 2.
>> switch_infnext    [ new_domid = 0x00000000
>>
>> However, if the guest domain is migrated from another host machine,  the
>> parsed trace file shows
>> switch_infprev    [ old_domid = 0x00007ffff
>> // the guest domain has a id of 2.
>> switch_infnext    [ new_domid = 0x00000000
>> Even the domain Id is 2, it shows 0x00007ffff.
>> Can anyone explain this? Thanks.
>>
>>
>>
>>
>> _______________________________________________
>> Xen-devel mailing list
>> Xen-devel@lists.xensource.com
>> http://lists.xensource.com/xen-devel
>>
>>     
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel
>
>
> .
>
>   

Re: Is this a bug of xentrace?

[Hui Kang]

Ok, I know that 0x00007fff is for the idle domain, because when I use 
xenmon it has the same idle domain. However, I have one guest domain 
running an infinite loop program (while{ int temp = 676*1.5;}). This 
guest domain is listed by "xm list". But xenmon and xentrace can not 
detect this guest domain.
However, when I stop the program in that domain, xentrace and xenmon can 
detect it. Why?
Thanks.

- Hui

Hui Kang wrote:
> Yes, it is 0x00007fff. This is one line  in the parsed trace file.
> CPU1  962569711226060 (+     574)  switch_infnext    [ new_domid = 
> 0x00007fff, time = 14321, r_time =30000000 ]
> When I use "xm list", it shows the domain id is 5. There are only two 
> domains on the host.
> Can any one point out what does "0x00007fff" this number mean? Thanks.
>
> - Hui
>
> George Dunlap wrote:
>> Are you sure that's not 0x7fff? (Three f's, not four?)  0x7fff is the
>> domain ID of the idle domain (scheduled when there is no other work on
>> the system to do).
>>
>>  -George
>>
>> On Sat, May 9, 2009 at 7:56 PM, Hui Kang <hkang@cs.sunysb.edu> wrote:
>>  
>>> Hi,
>>> I am using xentrace to trace the events of guest domains on a host 
>>> physical
>>> machine.  In the parsed trace file,
>>> if the guest domain is created on the host machine, then the entry 
>>> is good
>>> switch_infprev    [ old_domid = 0x00000002
>>> // the guest domain has a id of 2.
>>> switch_infnext    [ new_domid = 0x00000000
>>>
>>> However, if the guest domain is migrated from another host machine,  
>>> the
>>> parsed trace file shows
>>> switch_infprev    [ old_domid = 0x00007ffff
>>> // the guest domain has a id of 2.
>>> switch_infnext    [ new_domid = 0x00000000
>>> Even the domain Id is 2, it shows 0x00007ffff.
>>> Can anyone explain this? Thanks.
>>>
>>>
>>>
>>>
>>> _______________________________________________
>>> Xen-devel mailing list
>>> Xen-devel@lists.xensource.com
>>> http://lists.xensource.com/xen-devel
>>>
>>>     
>>
>> _______________________________________________
>> Xen-devel mailing list
>> Xen-devel@lists.xensource.com
>> http://lists.xensource.com/xen-devel
>>
>>
>> .
>>
>>   
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel
>
> .
>

Re: Is this a bug of xentrace?

[George Dunlap]

Perhaps because it's not being scheduled out?  If it never blocks, and
there's no one else who wants that cpu, there's no reason not to just
leave it running.

If you make another idle VM, and pin it and the spinning domain to the
same cpu, you'll probably see them both show up, as the idle VM is
scheduled to handle timers and such.

 -George

On Mon, May 11, 2009 at 5:46 PM, Hui Kang <hkang@cs.sunysb.edu> wrote:
> Ok, I know that 0x00007fff is for the idle domain, because when I use xenmon
> it has the same idle domain. However, I have one guest domain running an
> infinite loop program (while{ int temp = 676*1.5;}). This guest domain is
> listed by "xm list". But xenmon and xentrace can not detect this guest
> domain.
> However, when I stop the program in that domain, xentrace and xenmon can
> detect it. Why?
> Thanks.
>
> - Hui
>
> Hui Kang wrote:
>>
>> Yes, it is 0x00007fff. This is one line  in the parsed trace file.
>> CPU1  962569711226060 (+     574)  switch_infnext    [ new_domid =
>> 0x00007fff, time = 14321, r_time =30000000 ]
>> When I use "xm list", it shows the domain id is 5. There are only two
>> domains on the host.
>> Can any one point out what does "0x00007fff" this number mean? Thanks.
>>
>> - Hui
>>
>> George Dunlap wrote:
>>>
>>> Are you sure that's not 0x7fff? (Three f's, not four?)  0x7fff is the
>>> domain ID of the idle domain (scheduled when there is no other work on
>>> the system to do).
>>>
>>>  -George
>>>
>>> On Sat, May 9, 2009 at 7:56 PM, Hui Kang <hkang@cs.sunysb.edu> wrote:
>>>
>>>>
>>>> Hi,
>>>> I am using xentrace to trace the events of guest domains on a host
>>>> physical
>>>> machine.  In the parsed trace file,
>>>> if the guest domain is created on the host machine, then the entry is
>>>> good
>>>> switch_infprev    [ old_domid = 0x00000002
>>>> // the guest domain has a id of 2.
>>>> switch_infnext    [ new_domid = 0x00000000
>>>>
>>>> However, if the guest domain is migrated from another host machine,  the
>>>> parsed trace file shows
>>>> switch_infprev    [ old_domid = 0x00007ffff
>>>> // the guest domain has a id of 2.
>>>> switch_infnext    [ new_domid = 0x00000000
>>>> Even the domain Id is 2, it shows 0x00007ffff.
>>>> Can anyone explain this? Thanks.
>>>>
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> Xen-devel mailing list
>>>> Xen-devel@lists.xensource.com
>>>> http://lists.xensource.com/xen-devel
>>>>
>>>>
>>>
>>> _______________________________________________
>>> Xen-devel mailing list
>>> Xen-devel@lists.xensource.com
>>> http://lists.xensource.com/xen-devel
>>>
>>>
>>> .
>>>
>>>
>>
>>
>> _______________________________________________
>> Xen-devel mailing list
>> Xen-devel@lists.xensource.com
>> http://lists.xensource.com/xen-devel
>>
>> .
>>
>
>