Re: Real-Time Preemption, -RT-2.6.12-final-V0.7.50-24

From: Karsten Wiese
Date: Tue Jun 28 2005 - 21:14:03 EST


Am Dienstag, 28. Juni 2005 22:30 schrieb Ingo Molnar:
>
> * Ingo Molnar <mingo@xxxxxxx> wrote:
>
> >
> > * Karsten Wiese <annabellesgarden@xxxxxxxx> wrote:
> >
> > > Hi Ingo,
> > >
> > > suffering (not really ;-) double-rated IO-APIC level-interrupts I
> > > found the following patch as a solution:
> >
> > thanks. I've applied your patch but also tweaked this area a bit, to
> > make the i8259A PIC work too. I've uploaded the -31 patch with these
> > fixes included.
>
> make that -50-32, had a leftover hack in io_apic.c.
>
looked at -50-33 now and wonder why is mask_IO_APIC_irq() called twice
from __do_IRQ()?
given a threaded interrupt:
__do_IRQ() calls desc->handler->ack(irq).
ack points to mask_and_ack_level_ioapic_irq(), which calls mask_IO_APIC_irq(irq).
some lines later in __do_IRQ() desc->handler->disable(irq) is called.
disable points to mask_IO_APIC_irq(), now being called a 2nd time.
I think this 2nd call isn't necessary.
Is there a difference between masking an interrupt line and disabling it?
What am I missing?

Back at 2.6.12-rc5-RT-48-16 mask_and_ack_level_ioapic_irq() also contained the mask_IO_APIC_irq(irq)
call and level interrupt-rates where fine.
Some versions later it vanished there. Why was that?

Karsten









___________________________________________________________
Gesendet von Yahoo! Mail - Jetzt mit 1GB Speicher kostenlos - Hier anmelden: http://mail.yahoo.de
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/