Re: [PATCH v4 3/3] KVM: selftests: loongarch: Add PV TLB flush performance test

[Tao Cui <cui.tao@linux.dev>]

From: Tao Cui <cuitao@kylinos.cn>

Thanks, and I share the stability concern. I don't want to land something
that adds risk for a feature that isn't clearly earning its place yet.

> Do you have real workload to show the benefits of the PV TLB flush,
> and which TLB APIs should be hooked.

Completely fair, and to be upfront I don't have a large-scale real-world
workload to point to yet. So my plan is to build a set of local test
scripts that simulate as many usage scenarios as possible: mmap/fork-heavy
paths, kernel-range flushes, and an overcommitted setup where vCPU
preemption is frequent. I'll report the IPI and TLB-flush overhead with
and without the feature, broken down per flush API. The coverage is
synthetic rather than a single flagship workload, but hopefully it can at
least give us a rough, preliminary sense of whether the feature is worth
pursuing.

Thanks,
Tao