Re: [PATCH] kvm_irqchip_assign_irqfd: just set irqfd in case of kvm_irqfds_enabled()

Paolo Bonzini
2014-12-27T14:52:12Z

On 26/12/2014 18:59, Peter Maydell wrote:
> Mm, but once you're into such microoptimisations as this you really
> need to have a good justification for the effort, in the form of
> profiling measurements that indicate that this is a hot path.
> In this case that seems pretty unlikely, because I'd expect all
> the systems where we care about performance will support irqfds,
> so we won't be taking the early-exit code path anyhow. (And
> not supporting irqfds is leaving much more performance on the
> table than we could possibly be talking about in this function.)

Also, it's even possible for a compiler to figure this out. All in all,
I don't see any advantage to this patch...

Paolo