[PATCH] arm: omap4: allow disabling MPU local timer if 32K timer is enabled

[Russell King - ARM Linux]

On Sat, Feb 11, 2012 at 06:19:41PM +0800, Ming Lei wrote:
> On Sat, Feb 11, 2012 at 6:03 PM, Russell King - ARM Linux
> <linux at arm.linux.org.uk> wrote:
> > On Sat, Feb 11, 2012 at 04:31:25PM +0800, Ming Lei wrote:
> >> With 32K gp timer, tick can be driven and system can run well, so
> >> allow MPU local timer to be disabled if someone requires it, otherwise
> >> MPU local timer is always chosen as the default clock_event_device.
> >
> > The point being?
> 
> IMO, 32K gp timer may be more energy-saving than MPU local timer
> because gp timer has much less clock frequency and only half interrupts
> generated in tick mode compared with mpu local timer.
> 
> >
> > What if you want to use NO_HZ?
> 
> 32K gp timer supports oneshot mode, so it should support NO_HZ.  In my test
> .config, NO_HZ is enabled and system can run well.

Have you actually checked the tick rate of your timer in /proc/interrupts?
Have you checked /proc/timer_list to see what mode the system is in?