Re: is dynamic tick working?

[Tony Lindgren <tony@atomide.com>]

* David Brownell <david-b@pacbell.net> [060512 19:05]:
> On an OSK, using today's GIT tree, I turned on dynamic tick using
> sysfs and thought the IRQ rate (32 KHz timer) was odd.  So I did
> 
>   grep tim /proc/int*; sleep 60; grep tim /proc/int*
> 
> and saw 104551 IRQs, which is 1742 per second.  Too many!!  When
> I turned dyntick off (on/off via sysfs) the same measurement
> gave a more reasonable 7701 IRQs, making 128 per second.
> 
> In short, enabling dyntick got me 14x as many IRQs, instead of
> shrinking the number of IRQs.  Known bug?

Is this with touchscreen enabled? I saw something similar last week
where SPI was generating interrupts continuously. I think Imre has a
patch for that already available.

With dyntick the timer interrupt handler is being called also from
other interrupt handlers to update time. So doing something like:

$ cat /proc/interrupts; sleep 10; cat /proc/interrupts

might give you a clue which device interrupt is stuck.

In general dyntick should work, and you should see about 4-6HZ idle
tick rate.

Regards,

Tony