Messages in this thread | | | Date | Mon, 28 Jul 2014 01:36:16 +0800 | From | Yuyang Du <> | Subject | Re: [PATCH 2/2 v4] sched: Rewrite per entity runnable load average tracking |
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Hi Vincent,
On Fri, Jul 18, 2014 at 11:43:00AM +0200, Vincent Guittot wrote: > > @@ -2291,23 +2299,24 @@ static __always_inline int __update_entity_runnable_avg(u64 now, > > delta >>= 10; > > if (!delta) > > return 0; > > - sa->last_runnable_update = now; > > + sa->last_update_time = now; > > > > /* delta_w is the amount already accumulated against our next period */ > > - delta_w = sa->runnable_avg_period % 1024; > > + delta_w = sa->period_contrib; > > if (delta + delta_w >= 1024) { > > - /* period roll-over */ > > decayed = 1; > > > > + /* how much left for next period will start over, we don't know yet */ > > + sa->period_contrib = 0; > > + > > /* > > * Now that we know we're crossing a period boundary, figure > > * out how much from delta we need to complete the current > > * period and accrue it. > > */ > > delta_w = 1024 - delta_w; > > - if (runnable) > > - sa->runnable_avg_sum += delta_w; > > - sa->runnable_avg_period += delta_w; > > + if (w) > > + sa->load_sum += w * delta_w; > > Do you really need to have *w for computing the load_sum ? can't you > only use it when computing the load_avg ? > > sa->load_avg = div_u64(sa->load_sum * w , LOAD_AVG_MAX) >
For task, assuming its load.weight does not change much, yes, we can. But in theory, task's load.weight can change, and *w in load_sum can take into that change. For group entity and cfs_rq, its load.weight changes all the time, I don't know how to do it without *w for load_sum.
Sorry for my irresponsiveness for last week. I was on vacation and unfortunately failed to connect VPN from where I was.
Thanks, Yuyang
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