Messages in this thread | | | From | Vineeth Remanan Pillai <> | Date | Wed, 15 Apr 2020 17:24:30 -0400 | Subject | Re: [RFC PATCH 09/13] sched/fair: core wide vruntime comparison |
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> > > You forgot the time complexity analysis. > > > > This is a mistake and the adjust should be needed only once when core > > scheduling is initially enabled. It is an initialization thing and there > > is no reason to do it in every invocation of coresched_adjust_vruntime(). > > Correction... > I meant there is no need to call coresched_adjust_vruntime() in every > invocation of update_core_cfs_rq_min_vruntime().
Due to the checks in place, update_core_cfs_rq_min_vruntime should not be calling coresched_adjust_vruntime more than once between a coresched enable/disable. Once the min_vruntime is adjusted, we depend only on rq->core and the other sibling's min_vruntime will not grow until coresched disable.
I did some micro benchmark tests today to verify this and observed that coresched_adjust_vruntime called at most once between a coresched enable/disable.
Thanks, Vineeth
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