From: vincent.guittot@linaro.org (Vincent Guittot)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v5 04/12] sched: Allow all archs to set the capacity_orig
Date: Mon, 1 Sep 2014 10:05:09 +0200 [thread overview]
Message-ID: <CAKfTPtCNPYOi9OY37nbG9o71n4i5mxxvrRow0SgL_9pVK1LpMA@mail.gmail.com> (raw)
In-Reply-To: <540204DC.5090204@linux.vnet.ibm.com>
On 30 August 2014 19:07, Preeti U Murthy <preeti@linux.vnet.ibm.com> wrote:
> Hi Vincent,
>
> On 08/26/2014 04:36 PM, Vincent Guittot wrote:
>> capacity_orig is only changed for system with a SMT sched_domain level in order
>
> I think I had asked this before, but why only capacity_orig? The
> capacity of a group is also being updated the same way. This patch fixes
> the capacity of a group to reflect the capacity of the heterogeneous
> CPUs in it, this capacity being both the full capacity of the group:
> capacity_orig and the capacity available for the fair tasks. So I feel
> in the subject as well as the changelog it would suffice to say 'capacity'.
IIRC, we discussed that point on a former version. The patch changes
only the behavior of capacity_orig but the behavior of capacity stays
unchanged as all archs can already set the capacity whereas the
capacity_orig was configurable only if the SD_SHARE_CPUCAPACITY was
set in the sched_domain. This is no more the case with this patch
which creates arch_scale_cpu_capacity for setting capacity_orig.
>
>> to reflect the lower capacity of CPUs. Heterogenous system also have to reflect an
>> original capacity that is different from the default value.
>>
>> Create a more generic function arch_scale_cpu_capacity that can be also used by
>> non SMT platform to set capacity_orig.
>>
>> The weak behavior of arch_scale_cpu_capacity is the previous SMT one in order to
>> keep backward compatibility in the use of capacity_orig.
>>
>> arch_scale_smt_capacity and default_scale_smt_capacity have been removed as
>> they were not use elsewhere than in arch_scale_cpu_capacity.
>>
>> Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
>> ---
>> kernel/sched/fair.c | 25 ++++++-------------------
>> 1 file changed, 6 insertions(+), 19 deletions(-)
>>
>> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
>> index b85e9f7..8176bda 100644
>> --- a/kernel/sched/fair.c
>> +++ b/kernel/sched/fair.c
>> @@ -5705,19 +5705,12 @@ unsigned long __weak arch_scale_freq_capacity(struct sched_domain *sd, int cpu)
>> return default_scale_capacity(sd, cpu);
>> }
>>
>> -static unsigned long default_scale_smt_capacity(struct sched_domain *sd, int cpu)
>> +unsigned long __weak arch_scale_cpu_capacity(struct sched_domain *sd, int cpu)
>> {
>> - unsigned long weight = sd->span_weight;
>> - unsigned long smt_gain = sd->smt_gain;
>> + if ((sd->flags & SD_SHARE_CPUCAPACITY) && (sd->span_weight > 1))
>> + return sd->smt_gain / sd->span_weight;
>>
>> - smt_gain /= weight;
>> -
>> - return smt_gain;
>> -}
>> -
>> -unsigned long __weak arch_scale_smt_capacity(struct sched_domain *sd, int cpu)
>> -{
>> - return default_scale_smt_capacity(sd, cpu);
>> + return SCHED_CAPACITY_SCALE;
>> }
>>
>> static unsigned long scale_rt_capacity(int cpu)
>> @@ -5756,18 +5749,12 @@ static unsigned long scale_rt_capacity(int cpu)
>>
>> static void update_cpu_capacity(struct sched_domain *sd, int cpu)
>> {
>> - unsigned long weight = sd->span_weight;
>> unsigned long capacity = SCHED_CAPACITY_SCALE;
>> struct sched_group *sdg = sd->groups;
>>
>> - if ((sd->flags & SD_SHARE_CPUCAPACITY) && weight > 1) {
>> - if (sched_feat(ARCH_CAPACITY))
>
> Aren't you missing this check above? I understand that it is not
> crucial, but that would also mean removing ARCH_CAPACITY sched_feat
> altogether, wouldn't it?
Peter has proposed to remove all those checks and to keep only the
default behavior because no arch uses arch_scale_smt_capacity.
Then, ARCH_CAPACITY is still used in update_cpu_capacity
Regards,
Vincent
>
> Regards
> Preeti U Murthy
>> - capacity *= arch_scale_smt_capacity(sd, cpu);
>> - else
>> - capacity *= default_scale_smt_capacity(sd, cpu);
>> + capacity *= arch_scale_cpu_capacity(sd, cpu);
>>
>> - capacity >>= SCHED_CAPACITY_SHIFT;
>> - }
>> + capacity >>= SCHED_CAPACITY_SHIFT;
>>
>> sdg->sgc->capacity_orig = capacity;
>>
>
next prev parent reply other threads:[~2014-09-01 8:05 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 [this message]
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
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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