On Wed, Apr 10, 2019 at 12:36:33PM +0800, Aaron Lu wrote: > On Tue, Apr 09, 2019 at 11:09:45AM -0700, Tim Chen wrote: > > Now that we have accumulated quite a number of different fixes to your > > orginal > > posted patches. Would you like to post a v2 of the core scheduler with the > > fixes? > > One more question I'm not sure: should a task with cookie=0, i.e. tasks > that are untagged, be allowed to scheduled on the the same core with > another tagged task?
That was not meant to be possible. > The current patch seems to disagree on this, e.g. in pick_task(), > if max is already chosen but max->core_cookie == 0, then we didn't care > about cookie and simply use class_pick for the other cpu. This means we > could schedule two tasks with different cookies(one is zero and the > other can be tagged). When core_cookie==0 we shouldn't schedule the other siblings at all. > But then sched_core_find() only allow idle task to match with any tagged > tasks(we didn't place untagged tasks to the core tree of course :-). > > Thoughts? Do I understand this correctly? If so, I think we probably > want to make this clear before v2. I personally feel, we shouldn't allow > untagged tasks(like kernel threads) to match with tagged tasks. Agreed, cookie should always match or idle.