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SubjectRe: 2.6.11, IDE: Strange scheduling behaviour: high-pri RT process not scheduled?

* kus Kusche Klaus <kus@keba.com> 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
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