Re: [PATCH 0/7 v4] move update blocked load outside newidle_balance

[Valentin Schneider]

On 25/02/21 09:05, Vincent Guittot wrote:
>> One last thing for patch 7: mayhaps we could do a tad better to avoid
>> duplicate updates going through a heapful of leaf cfs rqs, see
>>
>>   http://lore.kernel.org/r/jhj4kiht7oh.mognet@xxxxxxx
>
> rq->last_blocked_load_update_tick is there only to filter duplicate
> update during _nohz_idle_balance but not for other normal LB.
>

Right, update_nohz_stats() is now only used in _nohz_idle_balance()...
IIUC the pattern being covered here would be a CPUX getting kicked for nohz
stats/balance, then some CPUX-N (so it gets picked by find_new_ilb())
entering idle and getting kick in turn (less than a jiffy apart).