答复: [PATCH] KVM: Consider SMT idle status when halt polling

[Li,Rongqing]

> -----邮件原件-----
> 发件人: Wanpeng Li <kernellwp@xxxxxxxxx>
> 发送时间: 2021年7月22日 13:55
> 收件人: Li,Rongqing <lirongqing@xxxxxxxxx>
> 抄送: Paolo Bonzini <pbonzini@xxxxxxxxxx>; Ingo Molnar
> <mingo@xxxxxxxxxx>; Peter Zijlstra <peterz@xxxxxxxxxxxxx>; kvm
> <kvm@xxxxxxxxxxxxxxx>; LKML <linux-kernel@xxxxxxxxxxxxxxx>
> 主题: Re: [PATCH] KVM: Consider SMT idle status when halt polling
> 
> On Thu, 22 Jul 2021 at 12:07, Li RongQing <lirongqing@xxxxxxxxx> wrote:
> >
> > SMT siblings share caches and other hardware, halt polling will
> > degrade its sibling performance if its sibling is busy
> 
> Do you have any real scenario benefits? As the polling nature, some cloud
> providers will configure to their preferred balance of cpu usage and
> performance, and other cloud providers for their NFV scenarios which are more
> sensitive to latency are vCPU and pCPU 1:1 pin，you
> destroy these setups.
>
>     Wanpeng

True, it benefits for our real scenario.

this patch can lower our workload compute latency in our multiple cores VM which vCPU and pCPU is 1:1 pin, and the workload with lots of computation and networking packets.

-Li