]> git.karo-electronics.de Git - linux-beck.git/commit
tick: Dynamically set broadcast irq affinity
authorDaniel Lezcano <daniel.lezcano@linaro.org>
Sat, 2 Mar 2013 10:10:11 +0000 (11:10 +0100)
committerThomas Gleixner <tglx@linutronix.de>
Thu, 7 Mar 2013 15:13:26 +0000 (16:13 +0100)
commitd2348fb6fdc6d671ad45b62db237f76c8c115603
tree30a05c397f91bd8ac32cc904231d9a72ce7b5c1e
parentf9ae39d04ccdec8d8ecf532191b7056c279a22c0
tick: Dynamically set broadcast irq affinity

When a cpu goes to a deep idle state where its local timer is
shutdown, it notifies the time frame work to use the broadcast timer
instead.  Unfortunately, the broadcast device could wake up any CPU,
including an idle one which is not concerned by the wake up at all. So
in the worst case an idle CPU will wake up to send an IPI to the CPU
whose timer expired.

Provide an opt-in feature CLOCK_EVT_FEAT_DYNIRQ which tells the core
that is should set the interrupt affinity of the broadcast interrupt
to the cpu which has the earliest expiry time. This avoids unnecessary
spurious wakeups and IPIs.

[ tglx: Adopted to cpumask rework, silenced an uninitialized warning,
  massaged changelog ]

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: viresh.kumar@linaro.org
Cc: jacob.jun.pan@linux.intel.com
Cc: linux-arm-kernel@lists.infradead.org
Cc: santosh.shilimkar@ti.com
Cc: linaro-kernel@lists.linaro.org
Cc: patches@linaro.org
Cc: rickard.andersson@stericsson.com
Cc: vincent.guittot@linaro.org
Cc: linus.walleij@stericsson.com
Cc: john.stultz@linaro.org
Link: http://lkml.kernel.org/r/1362219013-18173-3-git-send-email-daniel.lezcano@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
include/linux/clockchips.h
kernel/time/tick-broadcast.c