Re: [PATCH 4/4] sched/nohz_full: give correct cpu load for nohz_full cpu

Frederic, Would you like to give some comments on this patch?

Best Regard!

On 11/21/2013 01:45 PM, Alex Shi wrote:

When a nohz_full cpu in tickless mode, it may update cpu_load in following chain: __tick_nohz_full_check tick_nohz_restart_sched_tick update_cpu_load_nohz then it will be set a incorrect cpu_load: 0. This patch try to fix it and give it the correct cpu_load value.

Signed-off-by: Alex Shi alex.shi@linaro.org

kernel/sched/proc.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/kernel/sched/proc.c b/kernel/sched/proc.c index 057bb9b..5058e6a 100644 --- a/kernel/sched/proc.c +++ b/kernel/sched/proc.c @@ -477,10 +477,16 @@ void update_cpu_load_nohz(void) if (pending_updates) { this_rq->last_load_update_tick = curr_jiffies; /*

•  * We were idle, this means load 0, the current load might be
  

•  * !0 due to remote wakeups and the sort.
  

•  * We may has one task and in NO_HZ_FULL, then use normal
  

•  * cfs load.
  

•  * Or we were idle, this means load 0, the current load might
  

•  * be !0 due to remote wakeups and the sort.
  

  */

• __update_cpu_load(this_rq, 0);
  

• if (this_rq->cfs.h_nr_running) {
  

• 	unsigned load = get_rq_runnable_load(this_rq);
  

• 	__update_cpu_load(this_rq, load);
  

• } else
  

• 	__update_cpu_load(this_rq, 0);
  

  } raw_spin_unlock(&this_rq->lock);

}