On 06/07/2013 03:20 PM, Alex Shi wrote:
> They are the base values in load balance, update them with rq runnable
> load average, then the load balance will consider runnable load avg
> naturally.
>
> We also try to include the blocked_load_avg as cpu load in balancing,
> but that cause kbuild performance drop 6% on every Intel machine, and
> aim7/oltp drop on some of 4 CPU sockets machines.
Hi Alex,
Could you explain me why including the blocked_load_avg causes performance
drop ?
Thanks,
Gu
>
> Signed-off-by: Alex Shi <alex....@intel.com>
Reviewed-by: Gu Zheng <guz.f...@cn.fujitsu.com>
> ---
> kernel/sched/fair.c | 5 +++--
> kernel/sched/proc.c | 17 +++++++++++++++--
> 2 files changed, 18 insertions(+), 4 deletions(-)
>
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index 42c7be0..eadd2e7 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -2962,7 +2962,7 @@ static void dequeue_task_fair(struct rq *rq, struct
> task_struct *p, int flags)
> /* Used instead of source_load when we know the type == 0 */
> static unsigned long weighted_cpuload(const int cpu)
> {
> - return cpu_rq(cpu)->load.weight;
> + return cpu_rq(cpu)->cfs.runnable_load_avg;
> }
>
> /*
> @@ -3007,9 +3007,10 @@ static unsigned long cpu_avg_load_per_task(int cpu)
> {
> struct rq *rq = cpu_rq(cpu);
> unsigned long nr_running = ACCESS_ONCE(rq->nr_running);
> + unsigned long load_avg = rq->cfs.runnable_load_avg;
>
> if (nr_running)
> - return rq->load.weight / nr_running;
> + return load_avg / nr_running;
>
> return 0;
> }
> diff --git a/kernel/sched/proc.c b/kernel/sched/proc.c
> index bb3a6a0..ce5cd48 100644
> --- a/kernel/sched/proc.c
> +++ b/kernel/sched/proc.c
> @@ -501,6 +501,18 @@ static void __update_cpu_load(struct rq *this_rq,
> unsigned long this_load,
> sched_avg_update(this_rq);
> }
>
> +#ifdef CONFIG_SMP
> +unsigned long get_rq_runnable_load(struct rq *rq)
> +{
> + return rq->cfs.runnable_load_avg;
> +}
> +#else
> +unsigned long get_rq_runnable_load(struct rq *rq)
> +{
> + return rq->load.weight;
> +}
> +#endif
> +
> #ifdef CONFIG_NO_HZ_COMMON
> /*
> * There is no sane way to deal with nohz on smp when using jiffies because
> the
> @@ -522,7 +534,7 @@ static void __update_cpu_load(struct rq *this_rq,
> unsigned long this_load,
> void update_idle_cpu_load(struct rq *this_rq)
> {
> unsigned long curr_jiffies = ACCESS_ONCE(jiffies);
> - unsigned long load = this_rq->load.weight;
> + unsigned long load = get_rq_runnable_load(this_rq);
> unsigned long pending_updates;
>
> /*
> @@ -568,11 +580,12 @@ void update_cpu_load_nohz(void)
> */
> void update_cpu_load_active(struct rq *this_rq)
> {
> + unsigned long load = get_rq_runnable_load(this_rq);
> /*
> * See the mess around update_idle_cpu_load() / update_cpu_load_nohz().
> */
> this_rq->last_load_update_tick = jiffies;
> - __update_cpu_load(this_rq, this_rq->load.weight, 1);
> + __update_cpu_load(this_rq, load, 1);
>
> calc_load_account_active(this_rq);
> }
--
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