Re: [Qemu-devel] [PATCH] i386: Allow monitor / mwait cpuid override

[Wanpeng Li]

On 2/28/18 7:50 PM, Paolo Bonzini wrote:

> On 28/02/2018 00:55, Alexander Graf wrote:
>>
>> On 27.02.18 10:52, Gonglei (Arei) wrote:
>>> Hi all,
>>>
>>> Guests could achive good performance in 'Message Passing Workloads'
>>> scenarios when knowing the X86_FEATURE_MWAIT feature which is presented by 
>>> qemu.
>>> the reason is that after knowing that feature,
>>> the guest could use mwait method, which saves VMEXIT,
>>> to do idle, and achives high performace in latency-sensitive scenario.
>>>
>>> Is there any plan for this patch?
>>>
>>> Or May I send a updated version based on yours? @Alex?
>> Oh, did I drop the ball on this one? If that's the case, sure, go ahead.
> Hi, it is probably best to implement this feature based on the
> HINT_DEDICATED cpuid bit that Wanpeng Li is adding.

https://lkml.org/lkml/2018/2/13/624 As you pointed out, MWAIT/HLT/PAUSE 
non-exiting should be implemented at the same time and I'm still working 
on it. I will prepare patches for both the qemu and kvm stuffs. :)

Regards,
Wanpeng Li