Messages in this thread | | | From | Vineeth Pillai <> | Date | Mon, 23 Aug 2021 16:25:28 -0400 | Subject | Re: [PATCH] sched/core: fix pick_next_task 'max' tracking |
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Hi Peter,
> > Here, we should have instead updated 'max' when picking for SMT-1. Note > > that this code would eventually have righted itself, since the retry > > loop would re-pick p2, and update 'max' accordingly. However, this patch > > avoids the extra round-trip. > > Going with the observation Tao made; how about we rewrite the whole lot > to not be mind-bending complicated :-) > > How's this? It seems to build and pass the core-sched selftest thingy > (so it must be perfect, right? :-) > Nice, the code is much simpler now :-). A minor suggestion down..
> - for_each_cpu(i, smt_mask) { > - struct rq *rq_i = cpu_rq(i); > - > + /* > + * For each thread: do the regular task pick and find the max prio task > + * amongst them. > + * > + * Tie-break prio towards the current CPU > + */ > + for_each_cpu_wrap(i, smt_mask, cpu) { > + rq_i = cpu_rq(i); > rq_i->core_pick = NULL; > > if (i != cpu) > update_rq_clock(rq_i); > + > + for_each_class(class) { > + p = rq_i->core_temp = class->pick_task(rq_i); I think we can use core_pick to store the pick here and core_temp might not be required. What do you feel?
> + if (p) > + break; > + } > + > + if (!max || prio_less(max, p, fi_before)) > + max = p;
Thanks, Vineeth
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