My kernel is version 2.6.23, and I am getting variable interrupt frequencies. The settings when I go to make menuconfig are 250 Hz, which is what I want. But if I run the code found at
http://www.advenage.com/topics/linux...-frequency.php (referenced above) it tells me I have 126 Hz. My application, which is interrupt driven, runs anywhere from 125 to 250. There are a number of values I see, mainly 126, 135, 195, 223, and 250. When it runs at 250 it is very stable, but at the other values it always has a range of +/- about 5.
I have run my application on several other Linux operating systems, and it always runs rock steady at whatever the kernel is configured for. I have modified my include files to change HZ to 250 and am trying to recompile the kernel, but am having problems doing that (see another post I started today).
Does anyone know why the timer signal interrupts vary so much? The fact that it runs at 250 at times makes me think the settings in the kernel are probably set correctly. Has anyone experianced this variable phenomonen?