Re: [Xen-devel] how many processors does xen support in hardware?

[Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>]

Oh, right, yes that is Linux's configurable maximum (itself fairly arbitrary
really). You can't actually use that number on Xen, so don't set it so high.
Simple really. :-)

 -- Keir

On 24/8/07 19:00, "pradeep singh" <rautelap@xxxxxxxxx> wrote:

> On Friday 24 August 2007 20:19:07 Keir Fraser wrote:
>> Where did you get this number 255 from?
> 
> Sorry i meant, while i compile the xen kernel i can configure kernel upto a
> max of 255. right?
> 
> And i guess that means the number of CPUs you can compile your SMP kernel to
> work with. 
> what did i miss? :-/
> 
> thanks
> --pradeep
>> 
>>  K.
>> 
>> On 24/8/07 15:32, "pradeep singh rautela" <rautelap@xxxxxxxxx> wrote:
>>> On 8/24/07, Puthiyaparambil, Aravindh
>> 
>> <aravindh.puthiyaparambil@xxxxxxxxxx>
>> 
>>> wrote:
>>> Xen x86_32/PAE supports 32 logical CPUs. This is a hard limit and
>>> there is no easy way to increase this.
>>> 
>>> Xen x86_64 supports 64 logical
>>> CPUs. You need to compile Xen with max_phys_cpus=64 to enable this
>>> support. If you want to go beyond 126 LCPUs some patching is needed.
>>> 
>>> I guess you can
>>> theoretically go up to 255 but I think you might run out of GDT slots
>>> before that.
>> 
>> Right, so why keep 255 there at all? I mean why hard code it  to a
>> 
>>> max
>> 
>> 255 then?Put it at a number a little near or higher than what Xen
>> 
>>> is
>> 
>> actually capable of.
>> 
>> thanks
>> 
>>> Aravindh Puthiyaparambil
>>> Virtualization
>>> Engineer
>>> Virtual Systems Development
>>> Unisys, Tredyffrin PA
>>> 
>>> 
>>> -----Original Message-----
>>> From: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
>>> [mailto:xen-devel-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of tgh
>>> Sent:
>>> Friday, August 24, 2007 7:31 AM
>>> To: pradeep singh rautela
>>> Cc:
>>> xen-devel@xxxxxxxxxxxxxxxxxxx
>>> Subject: Re: [Xen-devel] how many processors
>>> does xen support in hardware?
>>> 
>>> pradeep singh rautela 写道:
>>>> On 8/24/07,
>>> 
>>> tgh <tianguanhua@xxxxxxxxxx> wrote:
>>>>> hi
>>>>>    how many processors
>>> 
>>> does xen support in hardware for the practical
>>> 
>>>>> system?
>>>> 
>>>> Thats
>>> 
>>> would be 255 i guess.
>>> 
>>> thank you for your reply
>>> but I want to kown the
>>> max number of hardware cpus the xen could
>>> support, or the xen's scalability
>>> in the aspect of cpu number,not in the
>>> aspect of the VM number
>>> 
>>> 
>>> thanks
>>> 
>>>> thanks
>>>> 
>>>>>   what is the max number of processors in
>>> 
>>> the practice system running
>>> 
>>>>> under xen ?
>>>>> 
>>>>> 
>>>>> 
>>>>> Thanks in
>>> 
>>> advance
>>> 
>>>>> _______________________________________________
>>> 
>>> Xen-devel mailing list
>>> 
>>>>> Xen-devel@xxxxxxxxxxxxxxxxxxx
>>> 
>>> http://lists.xensource.com/xen-devel
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> _______________________________________________
>>> Xen-devel mailing list
>>> 
>>> Xen-devel@xxxxxxxxxxxxxxxxxxx
>>> http://lists.xensource.com/xen-devel
>> 
>> --
>> 
>> --
>> pradeep singh rautela
>> 
>> "Genius is 1% inspiration, and 99% perspiration" -
>> 
>>> not me :)
>>> 
>>> _______________________________________________
>>> Xen-devel mailing list
>>> Xen-devel@xxxxxxxxxxxxxxxxxxx
>>> http://lists.xensource.com/xen-devel
> 
> 



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