On 19 October 2016 at 11:46, Dietmar Eggemann <dietmar.eggem...@arm.com> wrote: > On 18/10/16 12:56, Vincent Guittot wrote: >> Le Tuesday 18 Oct 2016 à 12:34:12 (+0200), Peter Zijlstra a écrit : >>> On Tue, Oct 18, 2016 at 11:45:48AM +0200, Vincent Guittot wrote: >>>> On 18 October 2016 at 11:07, Peter Zijlstra <pet...@infradead.org> wrote: > > [...] > >> >> The patch below fixes the issue on my platform: >> >> Dietmar, Omer can you confirm that this fix the problem of your platform too >> ? > > It fixes this broken BIOS issue on my T430 ( cpu_possible_mask > > cpu_online_mask). I ran the original test with the cpu hogs (stress -c > 4). Launch time of applications becomes normal again. > > Tested-by: Dietmar Eggemann <dietmar.eggem...@arm.com>
Thanks > > But this test only makes sure that we don't see any ghost contribution > (from non-existing cpus) any more. > > We should study the tg->se[i]->avg.load_avg for the hierarchy of tg's > (with the highest tg having a task enqueued) a little bit more, with and > without your v5 'sched: reflect sched_entity move into task_group's load'. Can you elaborate ? Vincent > >> --- >> kernel/sched/fair.c | 9 ++++++++- >> 1 file changed, 8 insertions(+), 1 deletion(-) >> >> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c >> index 8b03fb5..89776ac 100644 >> --- a/kernel/sched/fair.c >> +++ b/kernel/sched/fair.c >> @@ -690,7 +690,14 @@ void init_entity_runnable_average(struct sched_entity >> *se) >> * will definitely be update (after enqueue). >> */ >> sa->period_contrib = 1023; >> - sa->load_avg = scale_load_down(se->load.weight); >> + /* >> + * Tasks are intialized with full load to be seen as heavy task until >> + * they get a chance to stabilize to their real load level. >> + * group entity are intialized with null load to reflect the fact that >> + * nothing has been attached yet to the task group. >> + */ >> + if (entity_is_task(se)) >> + sa->load_avg = scale_load_down(se->load.weight); >> sa->load_sum = sa->load_avg * LOAD_AVG_MAX; >> /* >> * At this point, util_avg won't be used in select_task_rq_fair anyway
