Messages in this thread | | | Subject | Re: [RFC PATCH v3 06/10] sched: Add over-utilization/tipping point indicator | From | Dietmar Eggemann <> | Date | Tue, 19 Jun 2018 12:26:35 +0200 |
| |
On 06/19/2018 09:01 AM, Pavan Kondeti wrote: > On Mon, May 21, 2018 at 03:25:01PM +0100, Quentin Perret wrote:
[...]
>> @@ -8152,6 +8176,9 @@ static inline void update_sg_lb_stats(struct lb_env *env, >> if (nr_running > 1) >> *overload = true; >> >> + if (cpu_overutilized(i)) >> + *overutilized = 1; >> + > > There is no need to check if every CPU is overutilized or not once > *overutilized is marked as true, right?
True, so you want to check *overutilized before calling cpu_overutilized() to save a little bit on compute?
[...]
>> @@ -8586,6 +8621,10 @@ static struct sched_group *find_busiest_group(struct lb_env *env) >> * this level. >> */ >> update_sd_lb_stats(env, &sds); >> + >> + if (sched_energy_enabled() && !READ_ONCE(env->dst_rq->rd->overutilized)) >> + goto out_balanced; >> + > > Is there any reason for sending no-hz idle kicks but bailing out here when > system is not overutilized?
Even if a system is not-overutilized, we want to update stale cpu blocked load and utilization so NOHZ_STATS_KICK have to get through.
So calling find_busiest_group() -> update_sd_lb_stats() -> update_sg_lb_stats() to possibly execute update_nohz_stats() is IMHO the right thing to do.
| |