Re: [Xen-users] Bug or cofiguration error?

[Trolle Selander <trolle.selander@xxxxxxxxx>]

I'm getting the impression you're confused about what dom0 actually does; Xen is a Type-1 hypervisor, meaning DomUs don't run "in" dom0, and dom0 is really just another VM, albeit one with special privileges. You cannot use "standard" linux monitoring tools in dom0 to find out usage of host resources, since those tools will only show you what goes on within dom0, and as stated above, dom0 is just another domU along with any other domUs that happen to be running on the host. CPUs don't have to be available or online in dom0 for the hypervisor or other guest domains to put them to use. To see the actual host resource usage, you need to use the XCP management commands or xen-aware monitoring utilities like xentop.

Regards,

Trolle

On Thu, Mar 1, 2012 at 12:40 PM, Leonardo Pereira <leoudimg@xxxxxxxxx> wrote:

This affects the performance? Because mpstat shows the cpus 4...15 isn't used.


Em 1 de março de 2012 14:36, Trolle Selander
<trolle.selander@xxxxxxxxx> escreveu:

> It is neither a bug or a configuration error; XCP, like current versions of
> XenServer, only assigns 4 vCPUs to dom0 by default. There are very few
> scenarios where more dom0 vCPUs are beneficial.
>
> Regards,
> Trolle
>
> On Thu, Mar 1, 2012 at 11:57 AM, Leonardo Pereira <leoudimg@xxxxxxxxx>
> wrote:
>>
>> Hello,
>>
>> We are students of Computer Science and we are doing some
>> experiments with XCP, we have a server with 2 xeon processors each
>> one containing 4 physical cores with HT, but the XCP recognizes 16
>> cores (8 physical + 8 virtual) but uses only 4 (cpu 0,1,2 and 3).
>>  When accessing  "/ proc / cpuinfo" are listed only 4 cores, but
>> "/ sys / devices / system / cpu" lists 16 cores but the cpu file
>> "online" for 4 to 15 cpu's is set to "0".
>>
>> making:
>> echo 1> / sys/devices/system/cpu/cpu4/online
>> .
>> .
>> .
>> echo 1> / sys/devices/system/cpu/cpu15/online
>>
>> all cores become activated.
>> But when the server is restarted only cpus 0,1,2,3 are active.
>>
>> Is this a bug or a config error?
>>
>> Thanks.
>>
>> _______________________________________________
>> Xen-users mailing list
>> Xen-users@xxxxxxxxxxxxx
>> http://lists.xen.org/xen-users
>
>

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