From mboxrd@z Thu Jan  1 00:00:00 1970
From: Andrew Cooper <andrew.cooper3@citrix.com>
Subject: Re: cpuidle and un-eoid interrupts at the local apic
Date: Wed, 4 Sep 2013 21:54:45 +0100
Message-ID: <52279E15.4070207@citrix.com>
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	<52277CDA.8010401@digithi.de> <5227821A.9090201@citrix.com>
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To: "Thimo E." <abc@digithi.de>
Cc: Keir Fraser <keir@xen.org>, Jan Beulich <JBeulich@suse.com>, "Dong,
	Eddie" <eddie.dong@intel.com>, Xen-develList <xen-devel@lists.xen.org>, "Nakajima,
	Jun" <jun.nakajima@intel.com>, "Zhang,
	Yang Z" <yang.z.zhang@intel.com>, "Zhang,
	Xiantao" <xiantao.zhang@intel.com>
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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.

~Andrew