On Thu, Aug 02, 2018 at 05:24:15PM +0000, Bart Van Assche wrote: > On Fri, 2018-08-03 at 01:17 +0800, Ming Lei wrote: > > Not mentioning big CPU utilization is consumed unnecessarily for iterating > > over all queues even though there is only one active queue, is this fair from > > system view? > > I hope that someone will come up some day with a better solution than the > list_for_each_entry_rcu_rr() loop. But as long as such a solution has not yet > been found that loop should stay in order to preserve fair handling of large > numbers of LUNs. Again list_for_each_entry_rcu_rr() isn't fair for small number of active queue in this case, because this way decreases IOPS a lot and consumes CPU much just for checking all thousands of queues unnecessarily, even though 99% of them are idle. Thanks, Ming
