linux/kernel/time
Thomas Gleixner 26517f3e99 tick: Avoid programming the local cpu timer if broadcast pending
If the local cpu timer stops in deep idle, we arm the broadcast device
and get woken by an IPI. Now when we return from deep idle we reenable
the local cpu timer unconditionally before handling the IPI. But
that's a pointless exercise: the timer is already expired and the IPI
is on the way. And it's an expensive exercise as we use the forced
reprogramming mode so that we do not lose a timer event. This forced
reprogramming will loop at least once in the retry.

To avoid this reprogramming, we mark the cpu in a pending bit mask
before we send the IPI. Now when the IPI target cpu wakes up, it will
see the pending bit set and skip the reprogramming. The reprogramming
of the cpu local timer will happen in the IPI handler which runs the
cpu local timer interrupt function.

Reported-by: Jason Liu <liu.h.jason@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: LAK <linux-arm-kernel@lists.infradead.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Arjan van de Veen <arjan@infradead.org>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Link: http://lkml.kernel.org/r/20130306111537.431082074@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2013-03-13 11:39:39 +01:00
..
alarmtimer.c alarmtimer: Rename alarmtimer_remove to alarmtimer_dequeue 2012-09-24 12:38:03 -04:00
clockevents.c clockevents: export clockevents_config_and_register for module use 2013-01-14 10:12:37 -08:00
clocksource.c kernel-time: fix s/then/than/ spelling errors 2012-03-23 16:49:21 -07:00
jiffies.c time: Kill xtime_lock, replacing it with jiffies_lock 2012-11-13 14:08:23 -05:00
Kconfig Merge branch 'fortglx/3.9/time' of git://git.linaro.org/people/jstultz/linux into timers/core 2013-02-04 11:03:03 +01:00
Makefile time: remove the timecompare code. 2012-11-01 11:41:35 -04:00
ntp.c Merge branch 'core-locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2013-02-22 19:25:09 -08:00
posix-clock.c kernel: Fix files explicitly needing EXPORT_SYMBOL infrastructure 2011-10-31 19:30:05 -04:00
tick-broadcast.c tick: Avoid programming the local cpu timer if broadcast pending 2013-03-13 11:39:39 +01:00
tick-common.c tick: Convert broadcast cpu bitmaps to cpumask_var_t 2013-03-07 16:13:26 +01:00
tick-internal.h tick: Convert broadcast cpu bitmaps to cpumask_var_t 2013-03-07 16:13:26 +01:00
tick-oneshot.c clockevents: Make minimum delay adjustments configurable 2011-09-08 11:10:56 +02:00
tick-sched.c Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux 2013-02-28 19:48:26 -08:00
timeconv.c time: add function to convert between calendar time and broken-down time for universal use 2009-09-24 07:20:56 -07:00
timekeeping.c arm-soc: cleanups 2013-02-21 14:58:40 -08:00
timer_list.c nohz: Rename ts->idle_tick to ts->last_tick 2012-06-11 20:07:17 +02:00
timer_stats.c locking, timer_stats: Annotate table_lock as raw 2011-09-13 11:12:00 +02:00