"Paul E. McKenney" <paul...@linux.vnet.ibm.com> writes:
...
>
> commit 33103e7b1f89ef432dfe3337d2a6932cdf5c1312
> Author: Paul E. McKenney <paul...@linux.vnet.ibm.com>
> Date: Mon Aug 14 08:54:39 2017 -0700
>
> EXP: Trace tick return from tick_nohz_stop_sched_tick
>
> Signed-off-by: Paul E. McKenney <paul...@linux.vnet.ibm.com>
>
> diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
> index c7a899c5ce64..7358a5073dfb 100644
> --- a/kernel/time/tick-sched.c
> +++ b/kernel/time/tick-sched.c
> @@ -817,6 +817,7 @@ static ktime_t tick_nohz_stop_sched_tick(struct
> tick_sched *ts,
> * (not only the tick).
> */
> ts->sleep_length = ktime_sub(dev->next_event, now);
> + trace_printk("tick_nohz_stop_sched_tick: %lld\n", (tick - ktime_get())
> / 1000);
> return tick;
> }
Should I be seeing negative values? A small sample:
<idle>-0 [015] d... 1602.039695: __tick_nohz_idle_enter:
tick_nohz_stop_sched_tick: -1602250019
<idle>-0 [009] d... 1602.039701: __tick_nohz_idle_enter:
tick_nohz_stop_sched_tick: -1602250025
<idle>-0 [007] d... 1602.039702: __tick_nohz_idle_enter:
tick_nohz_stop_sched_tick: -1602250025
<idle>-0 [048] d... 1602.039703: __tick_nohz_idle_enter:
tick_nohz_stop_sched_tick: 9973
<idle>-0 [006] d... 1602.039704: __tick_nohz_idle_enter:
tick_nohz_stop_sched_tick: -1602250027
<idle>-0 [001] d... 1602.039730: __tick_nohz_idle_enter:
tick_nohz_stop_sched_tick: -1602250053
<idle>-0 [008] d... 1602.039732: __tick_nohz_idle_enter:
tick_nohz_stop_sched_tick: -1602250055
<idle>-0 [006] d... 1602.049695: __tick_nohz_idle_enter:
tick_nohz_stop_sched_tick: -1602260018
<idle>-0 [009] d... 1602.049695: __tick_nohz_idle_enter:
tick_nohz_stop_sched_tick: -1602260018
<idle>-0 [001] d... 1602.049695: __tick_nohz_idle_enter:
tick_nohz_stop_sched_tick: -1602260018
I have a full trace, I'll send it to you off-list.
cheers
