Re: [Xenomai-help] Frequency downscaling of new intel CPU

["Petr Cervenka" <grugh@domain.hid>]

> On Mon, Oct 3, 2011 at 4:39 AM, Petr Cervenka <grugh@domain.hid> wrote:

> >  Any ideas that could help me?

> What about looking at /proc/cpuinfo while running your system ? If you
> see that the speed is not the maximal, indeed, the frequency scaling
> system changes the speed of the processor.

/proc/cpuinfo shows always full frequency clock (3292.500 MHz)

More details:
1) two xenomai tasks are running with 100us period (controlled by external hardware)
2) one task communicates with hardware (receives data via rtnet) and passes them by rt_queue to the second task (on  another core)
3) second task does some computations and returns processed data to the first task
4) first task sends data to hardware

The problem is that during waiting on new data from hw CPU puts itself in some deeper idle state with lower frequency. A then, when the data are available, it slowly wakes up to normal state.
In other words: computation takes longer time than it takes on older computers (depends on overall CPU load).
When some artificial 100% load is running on another core, the computation is as fast as it should be.

Petr