On Mon, 2012-09-24 at 08:52 -0700, Linus Torvalds wrote: > And the whole "if we find any non-idle cpu, skip the whole domain" > logic really seems a bit odd (that's not new to your patch, though). > Can somebody explain what the whole point of that idiotically written > function is?
So we're looking for an idle cpu around @target. We prefer a cpu of an idle core, since SMT-siblings share L[12] cache. The way we do this is by iterating the topology tree downwards starting at the LLC (L3) cache level. Its groups are either the SMT-siblings or singleton groups. In case its the SMT things, we want to skip if there's a non-idle cpu in that mask to avoid sharing L[12]. If we don't find an empty core, we go down the domain tree, either finding a NULL domain and terminating, or finding the SMT domain, and we'll see if there's an idle SMT sibling. Is it pretty?, not really. Is there a better way of doing it?, possibly, I just haven't thought of it yet :/ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
