Messages in this thread | | | Date | Thu, 23 Mar 2017 07:08:24 -0700 | From | Steven Rostedt <> | Subject | Re: [PATCH v3 3/3] sched/rt: Add support for SD_PREFER_SIBLING on find_lowest_rq() |
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On Thu, 23 Mar 2017 19:36:51 +0900 Byungchul Park <byungchul.park@lge.com> wrote:
> On Thu, Mar 23, 2017 at 10:44:45AM +0100, Peter Zijlstra wrote: > > On Thu, Mar 23, 2017 at 11:12:49AM +0900, Byungchul Park wrote: > > > It would be better to avoid pushing tasks to other cpu within > > > a SD_PREFER_SIBLING domain, instead, get more chances to check > > > other siblings. > > > > Did you forget to post the rt equivalent to patch 1? > > No. Fortunately, rt currently works as patch 1 does.
I'm thinking that the rt and deadline search for lowest rq functions should be merged as one.
What they are doing is looking for the rq with the lowest priority. deadline currently doesn't care if it picks an rq with an rt task running on it, even when there's an rq with no rt tasks that the dl task can migrate to. The same goes with rt. It could place an RT task on an rq running a deadline task without knowing the rt task wont be able to run on that cpu immediately.
-- Steve
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