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Re: [Xen-devel] cpuidle and un-eoid interrupts at the local apic

On 04/09/2013 20:56, Thimo E. wrote:
> Hello Andrew,
> thanks for your response. At least I've seen the trigger of the new
> crash (2e) already before, so they seem so belong together.
> I can't image that I am the only one on the world who is using a
> haswell board. And as I haven't seen any other Xen bug/crash reports
> like mine (and one time you) nor bug reports from users with other
> operating systems, I ask myself if only my hardware is buggy
> or if other operating systems handle those "spurious" interrupts in
> another way ?!?!
> What does " ioapic_ack=old" change ?
> Best regards
>   Thimo

ioapic_ack=old is already in effect - see "Enabled directed EOI with
ioapic_ack_old on!" in the boot dmesg.

Originally, it was a bugfix workaround for ancient IO-APIC hardware
which had a bug on one of the mask bits.  Nowadays, it is used with EOI
broadcast suppression, which is a APIC transaction performance
improvement on recent processors.  What it does is affect whether an
IO-APIC interrupt gets masked when an interrupt is received.

You could certainly try "ioapic_ack=new" and see whether that makes a
difference, given a lack of any other ideas.  It will disable EOI
broadcast suppression.


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