Messages in this thread | | | Date | Mon, 23 Mar 2015 15:29:58 +0530 | From | Preeti U Murthy <> | Subject | Re: [PATCH v10 10/11] sched: add SD_PREFER_SIBLING for SMT level |
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On 03/23/2015 02:41 PM, Peter Zijlstra wrote: > On Tue, Mar 03, 2015 at 09:38:11AM +0100, Vincent Guittot wrote: > >>> Prefer siblings logic dates back to https://lkml.org/lkml/2009/8/27/210 >>> and only used in update_sd_lb_stats() where we have >>> >>> if (child && child->flags & SD_PREFER_SIBLING) >>> prefer_sibling = 1; >>> >>> However what confuses me is why should we even look at a child domain's >>> flag to balance tasks across the current sched domain? Why cant we just >>> set and use a sd flag at current level than to look at child domain >>> flag? >> >> Peter, >> have you got some insight about the reason ? > > Yeah, because it makes sense that way? ;-) > > The we want to move things to the child's sibling, not the parent's > sibling. We further need to have a child for this to make sense. > >
+1. The above is precisely why we need this patch.
Regards Preeti U Murthy
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