| Message ID | 1379371429-22214-1-git-send-email-khilman@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Frederic, On Mon, Sep 16, 2013 at 3:43 PM, Kevin Hilman <khilman@linaro.org> wrote: > Allow debugfs override of sched_tick_max_deferment in order to ease > finding/fixing the remaining issues with full nohz. > > The value to be written is in jiffies, and -1 means the max deferment > is disabled (scheduler_tick_max_deferment() returns KTIME_MAX.) > > Cc: Frederic Weisbecker <fweisbec@gmail.com> > Signed-off-by: Kevin Hilman <khilman@linaro.org> Any objections to this series for ease of debugging and tracking down issues with the residual tick? Kevin > --- > kernel/sched/core.c | 16 +++++++++++++++- > 1 file changed, 15 insertions(+), 1 deletion(-) > > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > index 5ac63c9..4b1fe3e 100644 > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -2175,6 +2175,8 @@ void scheduler_tick(void) > } > > #ifdef CONFIG_NO_HZ_FULL > +static u32 sched_tick_max_deferment = HZ; > + > /** > * scheduler_tick_max_deferment > * > @@ -2193,13 +2195,25 @@ u64 scheduler_tick_max_deferment(void) > struct rq *rq = this_rq(); > unsigned long next, now = ACCESS_ONCE(jiffies); > > - next = rq->last_sched_tick + HZ; > + if (sched_tick_max_deferment == -1) > + return KTIME_MAX; > + > + next = rq->last_sched_tick + sched_tick_max_deferment; > > if (time_before_eq(next, now)) > return 0; > > return jiffies_to_usecs(next - now) * NSEC_PER_USEC; > } > + > +static __init int sched_nohz_full_init_debug(void) > +{ > + debugfs_create_u32("sched_tick_max_deferment", 0644, NULL, > + &sched_tick_max_deferment); > + > + return 0; > +} > +late_initcall(sched_nohz_full_init_debug); > #endif > > notrace unsigned long get_parent_ip(unsigned long addr) > -- > 1.8.3 >
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 5ac63c9..4b1fe3e 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2175,6 +2175,8 @@ void scheduler_tick(void) } #ifdef CONFIG_NO_HZ_FULL +static u32 sched_tick_max_deferment = HZ; + /** * scheduler_tick_max_deferment * @@ -2193,13 +2195,25 @@ u64 scheduler_tick_max_deferment(void) struct rq *rq = this_rq(); unsigned long next, now = ACCESS_ONCE(jiffies); - next = rq->last_sched_tick + HZ; + if (sched_tick_max_deferment == -1) + return KTIME_MAX; + + next = rq->last_sched_tick + sched_tick_max_deferment; if (time_before_eq(next, now)) return 0; return jiffies_to_usecs(next - now) * NSEC_PER_USEC; } + +static __init int sched_nohz_full_init_debug(void) +{ + debugfs_create_u32("sched_tick_max_deferment", 0644, NULL, + &sched_tick_max_deferment); + + return 0; +} +late_initcall(sched_nohz_full_init_debug); #endif notrace unsigned long get_parent_ip(unsigned long addr)
Allow debugfs override of sched_tick_max_deferment in order to ease finding/fixing the remaining issues with full nohz. The value to be written is in jiffies, and -1 means the max deferment is disabled (scheduler_tick_max_deferment() returns KTIME_MAX.) Cc: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Kevin Hilman <khilman@linaro.org> --- kernel/sched/core.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-)