From: peterz@infradead.org (Peter Zijlstra)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v5 10/12] sched: get CPU's utilization statistic
Date: Thu, 11 Sep 2014 14:34:12 +0200 [thread overview]
Message-ID: <20140911123412.GY3190@worktop.ger.corp.intel.com> (raw)
In-Reply-To: <1409051215-16788-11-git-send-email-vincent.guittot@linaro.org>
On Tue, Aug 26, 2014 at 01:06:53PM +0200, Vincent Guittot wrote:
> Monitor the utilization level of each group of each sched_domain level. The
> utilization is the amount of cpu_capacity that is currently used on a CPU or
> group of CPUs. We use the usage_load_avg to evaluate this utilization level.
> In the special use case where the CPU is fully loaded by more than 1 task,
> the activity level is set above the cpu_capacity in order to reflect the overload
> of the CPU
>
> Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
> ---
> kernel/sched/fair.c | 19 ++++++++++++++++++-
> 1 file changed, 18 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index 1fd2131..2f95d1c 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -4126,6 +4126,11 @@ static unsigned long capacity_of(int cpu)
> return cpu_rq(cpu)->cpu_capacity;
> }
>
> +static unsigned long capacity_orig_of(int cpu)
> +{
> + return cpu_rq(cpu)->cpu_capacity_orig;
> +}
> +
> static unsigned long cpu_avg_load_per_task(int cpu)
> {
> struct rq *rq = cpu_rq(cpu);
This hunk should probably go into patch 6.
> @@ -4514,6 +4519,17 @@ static int select_idle_sibling(struct task_struct *p, int target)
> return target;
> }
>
> +static int get_cpu_utilization(int cpu)
> +{
> + unsigned long usage = cpu_rq(cpu)->cfs.usage_load_avg;
> + unsigned long capacity = capacity_of(cpu);
> +
> + if (usage >= SCHED_LOAD_SCALE)
> + return capacity + 1;
> +
> + return (usage * capacity) >> SCHED_LOAD_SHIFT;
> +}
So if I understood patch 9 correct, your changelog is iffy.
usage_load_avg should never get > 1 (of whatever unit), no matter how
many tasks are on the rq. You can only maximally run all the time.
Therefore I can only interpret the if (usage >= SCHED_LOAD_SCALE) as
numerical error handling, nothing more.
Also I'm not entirely sure I like the usage, utilization names/metrics.
I would suggest to reverse them. Call the pure running number
'utilization' and this scaled with capacity 'usage' or so.
> @@ -6188,7 +6206,6 @@ static inline void update_sd_lb_stats(struct lb_env *env, struct sd_lb_stats *sd
> /* Now, start updating sd_lb_stats */
> sds->total_load += sgs->group_load;
> sds->total_capacity += sgs->group_capacity;
> -
> sg = sg->next;
> } while (sg != env->sd->groups);
>
I like that extra line of whitespace, it separates the body from the
loop itself.
next prev parent reply other threads:[~2014-09-11 12:34 UTC|newest]
Thread overview: 79+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-08-26 11:06 [PATCH v5 00/12] sched: consolidation of cpu_capacity Vincent Guittot
2014-08-26 11:06 ` [PATCH v5 01/12] sched: fix imbalance flag reset Vincent Guittot
2014-08-26 11:06 ` [PATCH v5 02/12] sched: remove a wake_affine condition Vincent Guittot
2014-08-26 11:06 ` [PATCH v5 03/12] sched: fix avg_load computation Vincent Guittot
2014-08-30 12:00 ` Preeti U Murthy
2014-09-03 11:09 ` Vincent Guittot
2014-09-03 23:43 ` Tim Chen
2014-09-04 7:17 ` Vincent Guittot
2014-09-04 16:26 ` Tim Chen
2014-09-05 11:10 ` Preeti U Murthy
2014-08-26 11:06 ` [PATCH v5 04/12] sched: Allow all archs to set the capacity_orig Vincent Guittot
2014-08-27 13:12 ` Kamalesh Babulal
2014-08-30 17:07 ` Preeti U Murthy
2014-09-01 8:05 ` Vincent Guittot
2014-09-03 8:41 ` Preeti U Murthy
2014-09-10 13:50 ` Peter Zijlstra
2014-09-10 14:22 ` Vincent Guittot
2014-09-11 10:36 ` Preeti U Murthy
2014-08-26 11:06 ` [PATCH v5 05/12] ARM: topology: use new cpu_capacity interface Vincent Guittot
2014-09-11 18:52 ` Nicolas Pitre
2014-08-26 11:06 ` [PATCH v5 06/12] sched: add per rq cpu_capacity_orig Vincent Guittot
2014-08-27 13:32 ` Kamalesh Babulal
2014-08-28 7:34 ` Vincent Guittot
2014-09-10 13:53 ` Peter Zijlstra
2014-09-10 14:19 ` Vincent Guittot
2014-09-11 19:02 ` Nicolas Pitre
2014-09-15 21:22 ` Vincent Guittot
2014-08-26 11:06 ` [PATCH v5 07/12] sched: test the cpu's capacity in wake affine Vincent Guittot
2014-09-10 14:19 ` Peter Zijlstra
2014-08-26 11:06 ` [PATCH v5 08/12] sched: move cfs task on a CPU with higher capacity Vincent Guittot
2014-08-30 17:50 ` Preeti U Murthy
2014-09-01 8:45 ` Vincent Guittot
2014-09-03 9:11 ` Preeti U Murthy
2014-09-03 11:44 ` Vincent Guittot
2014-09-03 12:26 ` Preeti U Murthy
2014-09-03 12:49 ` Vincent Guittot
2014-09-11 9:27 ` Peter Zijlstra
2014-09-05 12:06 ` Preeti U Murthy
2014-09-05 12:24 ` Vincent Guittot
2014-09-11 10:07 ` Peter Zijlstra
2014-09-11 11:20 ` Vincent Guittot
2014-09-11 10:13 ` Peter Zijlstra
2014-09-11 12:14 ` Vincent Guittot
2014-09-11 11:54 ` Peter Zijlstra
2014-08-26 11:06 ` [PATCH v5 09/12] sched: add usage_load_avg Vincent Guittot
2014-09-04 7:34 ` [PATCH v5 09/11] " Vincent Guittot
2014-09-11 11:17 ` Peter Zijlstra
2014-09-11 11:17 ` [PATCH v5 09/12] " Peter Zijlstra
2014-09-11 12:18 ` Vincent Guittot
2014-09-11 12:20 ` Vincent Guittot
2014-09-15 19:15 ` Morten Rasmussen
2014-09-15 22:33 ` Vincent Guittot
2014-08-26 11:06 ` [PATCH v5 10/12] sched: get CPU's utilization statistic Vincent Guittot
2014-09-11 12:34 ` Peter Zijlstra [this message]
2014-09-11 13:07 ` Vincent Guittot
2014-09-11 14:04 ` Peter Zijlstra
2014-09-11 19:17 ` Nicolas Pitre
2014-09-12 7:41 ` Vincent Guittot
2014-09-15 19:45 ` Morten Rasmussen
2014-09-16 22:43 ` Vincent Guittot
2014-09-15 19:28 ` Morten Rasmussen
2014-08-26 11:06 ` [PATCH v5 11/12] sched: replace capacity_factor by utilization Vincent Guittot
2014-09-11 15:39 ` Peter Zijlstra
2014-09-11 16:15 ` Peter Zijlstra
2014-09-11 17:26 ` Vincent Guittot
2014-09-14 19:41 ` Peter Zijlstra
2014-09-14 19:51 ` Peter Zijlstra
2014-09-15 11:42 ` Peter Zijlstra
2014-09-15 19:07 ` Nicolas Pitre
2014-09-15 20:01 ` Peter Zijlstra
2014-09-17 18:45 ` Morten Rasmussen
2014-09-17 18:58 ` Morten Rasmussen
2014-09-17 23:03 ` Peter Zijlstra
2014-09-15 22:14 ` Vincent Guittot
2014-09-15 22:18 ` Vincent Guittot
2014-09-17 22:25 ` Peter Zijlstra
2014-09-18 1:32 ` Vincent Guittot
2014-09-16 17:00 ` Dietmar Eggemann
2014-08-26 11:06 ` [PATCH v5 12/12] sched: add SD_PREFER_SIBLING for SMT level Vincent Guittot
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