Re: [PATCH v5 06/12] sched: add per rq cpu_capacity_orig

On Tue, 26 Aug 2014, Vincent Guittot wrote:

This new field cpu_capacity_orig reflects the available capacity of a CPUs

s/a CPUs/a CPU/

unlike the cpu_capacity which reflects the current capacity that can be altered by frequency and rt tasks.

Shouldn't this be described as the "highest possible capacity" instead of only "available capacity" to make it clearer? In which case, shouldn't it be called capacity_max instead of capacity_orig? With "orig" we may think "origin" as the capacity that was available at boot time or the like. If for example the CPU was booted with a low P-state then its max capacity is different from the original one.

Signed-off-by: Vincent Guittot vincent.guittot@linaro.org

kernel/sched/core.c | 2 +- kernel/sched/fair.c | 1 + kernel/sched/sched.h | 1 + 3 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c index a394f99..7c3b237 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -7003,7 +7003,7 @@ void __init sched_init(void) #ifdef CONFIG_SMP rq->sd = NULL; rq->rd = NULL;

• rq->cpu_capacity = SCHED_CAPACITY_SCALE;
  

• rq->cpu_capacity = rq->cpu_capacity_orig = SCHED_CAPACITY_SCALE;
  

  rq->post_schedule = 0; rq->active_balance = 0; rq->next_balance = jiffies;

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 8176bda..17c16cc 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -5756,6 +5756,7 @@ static void update_cpu_capacity(struct sched_domain *sd, int cpu) capacity >>= SCHED_CAPACITY_SHIFT;

• cpu_rq(cpu)->cpu_capacity_orig = capacity; sdg->sgc->capacity_orig = capacity;

if (sched_feat(ARCH_CAPACITY)) diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index aa0f73b..7c0a74e 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -575,6 +575,7 @@ struct rq { struct sched_domain *sd; unsigned long cpu_capacity;

• unsigned long cpu_capacity_orig;

unsigned char idle_balance; /* For active balancing */ -- 1.9.1