Messages in this thread |  | | Date | Wed, 16 Aug 2017 23:04:14 +0900 | From | Byungchul Park <> | Subject | Re: [PATCH v6 1/2] sched/deadline: Add support for SD_PREFER_SIBLING on find_later_rq() |
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On Wed, Aug 16, 2017 at 09:32:44AM -0400, Steven Rostedt wrote: > On Wed, 16 Aug 2017 11:17:36 +0900 > Byungchul Park <byungchul.park@lge.com> wrote: > > > > Yes, that's what I intended. IOW: > > > > If (we found a proper sd, not having SD_PREFER_SIBLING?) > > use the sd; > > else if (we found a proper sd, having SD_PREFER_SIBLING?) > > use the smallest sd among SD_PREFER_SIBLING sds; > > BTW, what do you mean by "smallest sd"?
There might be more than one SD_PREFER_SIBLING domain in its hierachy. In that case, we have to choose one of them. Imagine the following example, in case that the source cpu is cpu 0:
[Domain hierachy for cpu 0]
cpu 0 -+ domain 1 -+ | SD_PREFER_SIBLING flaged | cpu 1 -+ +- domain 2 | SD_PREFER_SIBLING flaged cpu 2 -+---------------------------+ | cpu 3 -+
In this case, we have to choose domain 1 than 2, because cpus in domain 1 are closer to the source cpu, cpu 0. That's what I meant.
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