On 07/14/2013 12:14 AM, Arjan van de Ven wrote: > > > on thinking more about the short running task thing; there is an > optimization we currently don't do, > mostly for hyperthreading. (and HT is just one out of a set of cases > with similar power behavior) > If we know a task runs briefly AND is not performance critical, it's > much much better to place it on > a hyperthreading buddy of an already busy core than it is to place it on > an empty core (or to delay it). > Yes a HT pair isn't the same performance as a full core, but in terms of > power the 2nd half of a HT pair > is nearly free... so if there's a task that's not performance sensitive > (and won't disturb the other task too much, > e.g. runs briefly enough)... it's better to pack onto a core than to > spread. > you can generalize this to a class of systems where adding work to a > core (read: group of cpus that share resources) > is significantly cheaper than running on a full empty core.
Right! That is one of purpose that my old power sheduling's wanna do: https://lkml.org/lkml/2013/4/3/747 Vincent's patchset also target at this. -- Thanks Alex -- 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/
