Victor Iannello wrote:
>
> Paolo,
>
> Paolo,
>
> You are confirming what we suspected--the variation in time required to
> access the timer is a symptom rather than the cause of the jitter. You
> mention three possible causes at the hardware level--bus contention, DMA
> steals, and cache disruption. We have done some experiments with the cache
> turned off that have not improved jitter. So, we are probably at the
> hardware limits of x86 board architecture. It never was designed for
> cycle-by-cycle determinism.
>
Agreed.
Note that I tried disabling the cache but rebooted immediately just
after looking at how long it took to boot, I needed computational
power, not less than 15 us jitter.
I also suspect that what you say is not just an ix86 fault. From my
limited experience of PPC under RTAI it seems I got similar results.
Ciao, Paolo.
-- [rtl] ---
To unsubscribe:
echo "unsubscribe rtl" | mail [EMAIL PROTECTED] OR
echo "unsubscribe rtl <Your_email>" | mail [EMAIL PROTECTED]
---
For more information on Real-Time Linux see:
http://www.rtlinux.org/rtlinux/
