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RE: [Xen-devel] [PATCH] Enlarge default NR_CPUS to 64 for x86_64

To: Keir Fraser <keir.fraser@xxxxxxxxxxxxx>, Jan Beulich <JBeulich@xxxxxxxxxx>
Subject: RE: [Xen-devel] [PATCH] Enlarge default NR_CPUS to 64 for x86_64
From: "Wei, Gang" <gang.wei@xxxxxxxxx>
Date: Fri, 7 Aug 2009 23:09:12 +0800
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Thread-topic: [Xen-devel] [PATCH] Enlarge default NR_CPUS to 64 for x86_64
Yes, it is. We can push to 128 if there really are a lot of needs. The slightly 
side-effect is a little larger default memory footprint for hypervisor if not 
really need to support that much of pcpus. We can do it step by step.

Jimmy

Keir Fraser wrote:
> Yes indeed. We could push to 128 no problem. I think Intel's only
> concern is that 64 is as much as they test currently.
> 
> -- Keir
> 
> On 07/08/2009 11:02, "Jan Beulich" <JBeulich@xxxxxxxxxx> wrote:
> 
>> I think there's little point in having both have the same limit. I'd
>> rather question whether the limit shouldn't be pushed up higher for
>> x86-64. 
>> 
>> Jan
>> 
>>>>> Keir Fraser <keir.fraser@xxxxxxxxxxxxx> 07.08.09 11:52 >>>
>> Shall we just bump it for i386 too?
>> 
>>  -- Keir
>> 
>> On 07/08/2009 10:37, "Wei, Gang" <gang.wei@xxxxxxxxx> wrote:
>> 
>>> By far a lot of systems are with more sockets (>=4), more cores
>>> (>=8), meanwhile with HyperThread, so enlarge the default NR_CPUS
>>> would easier the build for more threads systems.
>>> 
>>> Jimmy
>>> 
>>> -------------------------------------------------------------
>>> Enlarge default NR_CPUS to 64 for x86_64.
>>> 
>>> Signed-off-by: Wei Gang <gang.wei@xxxxxxxxx>
>>> 
>>> diff -r b9cdcf502aa3 xen/include/asm-x86/config.h
>>> --- a/xen/include/asm-x86/config.h Thu Aug 06 11:14:48 2009 +0100
>>> +++ b/xen/include/asm-x86/config.h Fri Aug 07 14:54:06 2009 +0800
>>>  @@ -49,7 +49,11 @@ #ifdef MAX_PHYS_CPUS
>>>  #define NR_CPUS MAX_PHYS_CPUS
>>>  #else
>>> +#ifdef __i386__
>>>  #define NR_CPUS 32
>>> +#else
>>> +#define NR_CPUS 64
>>> +#endif
>>>  #endif
>>> 
>>>  #ifdef __i386__
>> 
>> 
>> 
>> _______________________________________________
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