[PATCH v5 04/12] sched: Allow all archs to set the capacity_orig
From: Preeti U Murthy <hidden>
Date: 2014-08-30 17:07:53
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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'.
quoted hunk ↗ jump to hunk
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? 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;