On Mon, Aug 06, 2007 at 08:14:59AM +0200, Ingo Molnar wrote:
Alas, there still could be something more... To be more sure, even
with this, there should be some debug printk (which could mess too),
but I don't know how much patience (and similar boxes...) Marcin has.
Of course, this "temporary fix" in -rc2 should give us more time.
But, I think you should confirm this gain with levels (I mean there
could be some saving on flag setting/ checking too). E.g. I've thought
about adding another ioapic_chip struct for fasteoi without .retrigger
(and maybe with .disable = .mask) maybe with some #ifdef CONFIG_...,
but maybe there could be reconsidered IRQ_DELAYED_DISABLE too (but
with this, there probably was a possibility to run this hw ->retrigger
'by chance' too, so with some strange IO-APICS there would be still
an unnecessary risk here).
The big question for me is still why this isn't more common: it seems
some (most of?) IO-APICS have some safety against this?
BTW: Marcin, if you're still willing to test anything (and your box is
alive after my previous 'could not make any damage' patch - sorry!),
this should be done with something before -rc2, so 2.6.22 or .23-rc1.
PS: I've just read Marcin's messages - so, happily, it seems
everybody's alive! Thanks.