[Devel] Re: [PATCH v3 1/6] measure exec_clock for rt sched entities

[Peter Zijlstra]

On Wed, 2012-05-30 at 13:48 +0400, Glauber Costa wrote:
> For simetry with the cfq tasks, measure exec_clock for the rt
> sched entities (rt_se).

Symmetry methinks.. anyway, where is the symmetry?, fair.c:update_curr()
doesn't do the for_each_sched_entity() thing.

> This can be used in a number of fashions. For instance, to
> compute total cpu usage in a cgroup that is generated by
> rt tasks.
> 
> Signed-off-by: Glauber Costa <glommer at parallels.com>
> CC: Peter Zijlstra <a.p.zijlstra at chello.nl>
> CC: Paul Turner <pjt at google.com>
> ---
>  kernel/sched/rt.c    |    5 +++++
>  kernel/sched/sched.h |    1 +
>  2 files changed, 6 insertions(+)
> 
> diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
> index c5565c3..30ee4e2 100644
> --- a/kernel/sched/rt.c
> +++ b/kernel/sched/rt.c
> @@ -919,6 +919,11 @@ static void update_curr_rt(struct rq *rq)
>  
>  	sched_rt_avg_update(rq, delta_exec);
>  
> +	for_each_sched_rt_entity(rt_se) {
> +		rt_rq = rt_rq_of_se(rt_se);
> +		schedstat_add(rt_rq, exec_clock, delta_exec);
> +	}
> +
>  	if (!rt_bandwidth_enabled())
>  		return;

See, this just makes me sad.. you now have a double
for_each_sched_rt_entity() loop.