lkml.org 
[lkml]   [2020]   [Mar]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: [PATCH V2] sched: fair: Use the earliest break even
Date

Hi Daniel,

One more comment on the break even itself, ignoring the rest:

On Wed, Mar 11 2020, Daniel Lezcano wrote:
> diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
> index b743bf38f08f..3342e7bae072 100644
> --- a/kernel/sched/idle.c
> +++ b/kernel/sched/idle.c
> @@ -19,7 +19,13 @@ extern char __cpuidle_text_start[], __cpuidle_text_end[];
> */
> void sched_idle_set_state(struct cpuidle_state *idle_state)
> {
> - idle_set_state(this_rq(), idle_state);
> + struct rq *rq = this_rq();
> +
> + idle_set_state(rq, idle_state);
> +
> + if (idle_state)
> + idle_set_break_even(rq, ktime_get_ns() +
> + idle_state->exit_latency_ns);

I'm not sure I follow why we go for entry time + exit latency. If this
is based on the minimum residency, shouldn't this be something depending
on the entry latency? i.e. something like

break_even = now + entry_latency + idling_time
\_________________________/
min-residency

or am I missing something?

> }
>
> static int __read_mostly cpu_idle_force_poll;

\
 
 \ /
  Last update: 2020-03-17 11:57    [W:0.777 / U:0.084 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site