Cort Dougan wrote:
> } I was just wondering if programming the timer in one-shot mode might cause the
> } normal system timer interrupt to be called at an unusual interval (thus
> } affecting the jiffie count, etc). Seems that the linux layer will get its fake
> } timer interrupt when (and only when) the one-shot fires.
>
> We make certain that the Linux timer is monotonically increasing. If you
> take a look at arch/i386/kernel/time.c you'll see changes to gettimeofday
> that cooperate with RTLinux.
>
I looked. You patch do_gettimeoffset at runtime. So anybody who accesses the Linux
timer via this interface will see the timer monotonically increasing. Ok.
But I don't think it answers my question.
For example, assume the linux timer interrupt fires 100 times a second (every
10msec). An RT task programs the one-shot timer to go off in 20 msec. The timer
interrupt fires at the programmed time. The RT interrupt handler calls the kernel
timer interrupt handler 10 msec later than normal. Normally, the linux timer
interrupt updates the jiffie count (among other things). So we effectively lose a
jiffie increment. I'm not sure what other side effects might occur.
Is this untrue or does it just not matter?
--Gordon
-- [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/
