Re: [RFC PATCH 0/2] Mitigating Excessive Pause-Loop Exiting in VM-Agnostic KVM

[Sean Christopherson]

On Thu, Apr 22, 2021, Kenta Ishiguro wrote:
> To solve problems (2) and (3), patch 2 monitors IPI communication between
> vCPUs and leverages the relationship between vCPUs to select boost
> candidates.  The "[PATCH] KVM: Boost vCPU candidiate in user mode which is
> delivering interrupt" patch
> (https://lore.kernel.org/kvm/CANRm+Cy-78UnrkX8nh5WdHut2WW5NU=UL84FRJnUNjsAPK+Uww@xxxxxxxxxxxxxx/T/)
> seems to be effective for (2) while it only uses the IPI receiver
> information.

On the IPI side of thing, I like the idea of explicitly tracking the IPIs,
especially if we can simplify the implementation, e.g. by losing the receiver
info and making ipi_received a bool.  Maybe temporarily table Wanpeng's patch
while this approach is analyzed?