Re: [Qemu-devel] [PATCH] x86: Increase max vcpu number to 352

[Radim Krčmář]

2017-08-10 19:02+0800, Lan Tianyu:
> On 2017年08月10日 18:26, Daniel P. Berrange wrote:
>> On Thu, Aug 10, 2017 at 06:08:07PM +0800, Lan Tianyu wrote:
>>> Intel Xeon phi chip will support 352 logical threads. For HPC
>>> usage case, it will create a huge VM with vcpus number as same as host
>>> cpus. This patch is to increase max vcpu number to 352.
>> 
>> If we pick arbitray limits based on size of physical CPUs that happen
>> to be shipping today, we'll continue the cat+mouse game forever trailing
>> latest CPUs that vendors ship.
>> 
>> IMHO we should pick a higher number influenced by technical constraints
>> of the q35 impl instead. eg can we go straight to something like 512 or
>> 1024  ?
> 
> Sure. 512 should be enough and some arrays is defined according to max
> vcpu number.

Hm, which arrays are that?  I was thinking it is safe to bump it to
INT_MAX as the number is only used when setting global max_cpus.

Thanks.