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Groups > linux.kernel > #1374150
| From | Peter Zijlstra <peterz@infradead.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH 3/3] sched: Optimize !CONFIG_NO_HZ_COMMON cpu load updates |
| Date | 2016-04-08 12:50 +0200 |
| Message-ID | <rlC9b-2s3-13@gated-at.bofh.it> (permalink) |
| References | <rlt5T-4eY-1@gated-at.bofh.it> <rlt5T-4eY-7@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Fri, Apr 08, 2016 at 03:07:13AM +0200, Frederic Weisbecker wrote:
> index 4c522a7..59a2821 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -7327,8 +7327,9 @@ void __init sched_init(void)
>
> for (j = 0; j < CPU_LOAD_IDX_MAX; j++)
> rq->cpu_load[j] = 0;
> -
> +#ifdef CONFIG_NO_HZ_COMMON
> rq->last_load_update_tick = jiffies;
> +#endif
>
> #ifdef CONFIG_SMP
> rq->sd = NULL;
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index 1dd864d..4618e5b 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -4661,8 +4680,10 @@ static inline void cpu_load_update_nohz(struct rq *this_rq,
>
> static void cpu_load_update_periodic(struct rq *this_rq, unsigned long load)
> {
> +#ifdef CONFIG_NO_HZ_COMMON
> /* See the mess around cpu_load_update_nohz(). */
> this_rq->last_load_update_tick = READ_ONCE(jiffies);
> +#endif
> cpu_load_update(this_rq, load, 1);
> }
>
Here you do the simple #ifdef, while here you make a giant mess instead
of the relatively straight forward:
> @@ -4540,17 +4568,8 @@ static void cpu_load_update(struct rq *this_rq, unsigned long this_load,
>
> /* scale is effectively 1 << i now, and >> i divides by scale */
>
> - old_load = this_rq->cpu_load[i];
#ifdef CONFIG_NO_HZ_COMMON
> - old_load = decay_load_missed(old_load, pending_updates - 1, i);
> - if (tickless_load) {
> - old_load -= decay_load_missed(tickless_load, pending_updates - 1, i);
> - /*
> - * old_load can never be a negative value because a
> - * decayed tickless_load cannot be greater than the
> - * original tickless_load.
> - */
> - old_load += tickless_load;
> - }
#endif
> new_load = this_load;
> /*
> * Round up the averaging division if load is increasing. This
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[PATCH 0/3] sched: Fix/improve nohz cpu load updates v2 Frederic Weisbecker <fweisbec@gmail.com> - 2016-04-08 03:10 +0200
[PATCH 2/3] sched: Correctly handle nohz ticks cpu load accounting Frederic Weisbecker <fweisbec@gmail.com> - 2016-04-08 03:10 +0200
Re: [PATCH 2/3] sched: Correctly handle nohz ticks cpu load accounting Peter Zijlstra <peterz@infradead.org> - 2016-04-08 11:50 +0200
Re: [PATCH 2/3] sched: Correctly handle nohz ticks cpu load accounting Frederic Weisbecker <fweisbec@gmail.com> - 2016-04-08 15:00 +0200
Re: [PATCH 2/3] sched: Correctly handle nohz ticks cpu load accounting Peter Zijlstra <peterz@infradead.org> - 2016-04-08 19:50 +0200
[PATCH 1/3] sched: Gather cpu load functions under a more conventional namespace Frederic Weisbecker <fweisbec@gmail.com> - 2016-04-08 03:10 +0200
[PATCH 3/3] sched: Optimize !CONFIG_NO_HZ_COMMON cpu load updates Frederic Weisbecker <fweisbec@gmail.com> - 2016-04-08 03:10 +0200
Re: [PATCH 3/3] sched: Optimize !CONFIG_NO_HZ_COMMON cpu load updates Peter Zijlstra <peterz@infradead.org> - 2016-04-08 12:50 +0200
Re: [PATCH 3/3] sched: Optimize !CONFIG_NO_HZ_COMMON cpu load updates Frederic Weisbecker <fweisbec@gmail.com> - 2016-04-08 15:00 +0200
Re: [PATCH 3/3] sched: Optimize !CONFIG_NO_HZ_COMMON cpu load updates Peter Zijlstra <peterz@infradead.org> - 2016-04-08 19:50 +0200
Re: [PATCH 3/3] sched: Optimize !CONFIG_NO_HZ_COMMON cpu load updates Frederic Weisbecker <fweisbec@gmail.com> - 2016-04-11 15:20 +0200
Re: [PATCH 3/3] sched: Optimize !CONFIG_NO_HZ_COMMON cpu load updates Frederic Weisbecker <fweisbec@gmail.com> - 2016-04-11 20:30 +0200
Re: [PATCH 3/3] sched: Optimize !CONFIG_NO_HZ_COMMON cpu load updates Peter Zijlstra <peterz@infradead.org> - 2016-04-12 16:30 +0200
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