Messages in this thread | | | Date | Wed, 03 Apr 2013 09:02:17 +0800 | From | Alex Shi <> | Subject | Re: [patch v6 03/21] sched: only count runnable avg on cfs_rq's nr_running |
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On 04/02/2013 10:30 PM, Vincent Guittot wrote: > On 30 March 2013 15:34, Alex Shi <alex.shi@intel.com> wrote: >> Old function count the runnable avg on rq's nr_running even there is >> only rt task in rq. That is incorrect, so correct it to cfs_rq's >> nr_running. >> >> Signed-off-by: Alex Shi <alex.shi@intel.com> >> --- >> kernel/sched/fair.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c >> index 2881d42..026e959 100644 >> --- a/kernel/sched/fair.c >> +++ b/kernel/sched/fair.c >> @@ -2829,7 +2829,7 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags) >> } >> >> if (!se) { >> - update_rq_runnable_avg(rq, rq->nr_running); >> + update_rq_runnable_avg(rq, rq->cfs.nr_running); > > A RT task that preempts your CFS task will be accounted in the > runnable_avg fields. So whatever you do, RT task will impact your > runnable_avg statistics. Instead of trying to get only CFS tasks, you > should take into account all tasks activity in the rq.
Thanks for comments, Vincent!
Yes, I know some rt task time was counted into cfs, but now we have no good idea to remove them clearly. So I just want to a bit more precise cfs runnable load here. On the other side, periodic LB balance on combined the cfs/rt load, but removed the RT utilisation in cpu_power.
So, PJT, Peter, what's your idea of this point? > > Vincent >> inc_nr_running(rq); >> } >> hrtick_update(rq); >> -- >> 1.7.12 >>
-- Thanks Alex
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