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'.
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);elsecapacity *= 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;