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
