* kus Kusche Klaus [off-list ref] wrote:

I've written a small test program which enables periodic RTC 
interrupts at 8192 Hz and then goes into a loop reading /dev/rtc and 
collecting timing statistics (using the rdtscl macro).

getting /dev/rtc handling right for latency measurement is ... tricky.  
The method i'm using under PREEMPT_RT is:

 chrt -f 84 -p `pidof 'IRQ 0'`
 chrt -f 95 -p `pidof 'IRQ 8'`
 ./rtc_wakeup -f 1024 -t 100000

you can get rtc_wakeup from:

 http://www.affenbande.org/~tapas/wiki/index.php?rtc_wakeup

written by Florian Schmidt.

do you see high latencies even with rtc_wakeup?

	Ingo