Messages in this thread | | | Date | Thu, 21 Oct 2010 15:22:21 +0530 | From | Bharata B Rao <> | Subject | Re: [RFC tg_shares_up improvements - v1 05/12] sched: fix update_cfs_load synchronization |
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On Fri, Oct 15, 2010 at 09:43:54PM -0700, pjt@google.com wrote: > Using cfs_rq->nr_running is not sufficient to synchronize update_cfs_load with > the put path since nr_running accounting occurs at deactivation. > > It's also not safe to make the removal decision based on load_avg as this fails > with both high periods and low shares. Resolve this by clipping history at 8 > foldings. >
Did you mean 4 foldings (and not 8) above since I see you are truncating the load history at 4 idle periods ?
> @@ -685,9 +686,19 @@ static void update_cfs_load(struct cfs_r > now = rq_of(cfs_rq)->clock; > delta = now - cfs_rq->load_stamp; > > + /* truncate load history at 4 idle periods */ > + if (cfs_rq->load_stamp > cfs_rq->load_last && > + now - cfs_rq->load_last > 4 * period) { > + cfs_rq->load_period = 0; > + cfs_rq->load_avg = 0; > + } > + > cfs_rq->load_stamp = now; > cfs_rq->load_period += delta; > - cfs_rq->load_avg += delta * cfs_rq->load.weight; > + if (load) { > + cfs_rq->load_last = now; > + cfs_rq->load_avg += delta * load; > + } > > while (cfs_rq->load_period > period) { > /* > @@ -700,10 +711,8 @@ static void update_cfs_load(struct cfs_r > cfs_rq->load_avg /= 2; > } > > - if (lb && !cfs_rq->nr_running) { > - if (cfs_rq->load_avg < (period / 8)) > - list_del_leaf_cfs_rq(cfs_rq); > - } > + if (!cfs_rq->curr && !cfs_rq->nr_running && !cfs_rq->load_avg) > + list_del_leaf_cfs_rq(cfs_rq); > } >
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